EP2572425A2 - System for recovering renewable energy - Google Patents

Abstract

The invention relates to a system (1) for recovering renewable energy, comprising a heat pump system (2) with at least one electric motor (16, 16') for a compressor (14) or a fluid circulation pump (18a, 18b), at least one photovoltaic solar panel (3), and an AC-DC/DC electronic converter (4) interconnected between the solar panels and the heat pump system. The system comprises at least one frequency variator (16, 16') connected to a DC outlet (24, 25) of the converter and to the electric motor for feeding and controlling the electric motor.

Description

 Renewable energy recovery system

The present invention relates to a renewable energy recovery system, including geothermal energy by a heat pump system.

Conventional heat pumps recover thermal energy from the ground or from the air and for this need pumps for the circulation of fluids and a compressor for the phase change of the fluid used for heat exchange. Heat pumps are mainly used in buildings for heating in winter, or for heating swimming pools. Despite the use of renewable energy, heat pumps nevertheless require between 35 and 50% of electrical energy of the network for the supply of the electric motors of the circulators and the compressor.

To reduce non-renewable energy consumption, it is conceivable to use other energy sources such as photovoltaic solar panels or wind turbines. Wind turbine or photovoltaic solar panel installations are relatively expensive and their connection to the electrical system of a residence or building is a problem in many countries, among other things because one can not inject current in the public network, even if technical solutions exist. Solar energy and / or wind energy, however, are unpredictable and / or variable and do not allow to ensure, continuously and as needed, the electrical energy needed for a residence, building or other construction . The use of renewable energy systems is now generally more expensive than the energy available from the public grid, the cost of installing and operating renewable energy systems such as heat pumps or solar panels. Solar photovoltaic is an important criterion for the commercialization of such systems. It is known to connect solar panels to an energy recovery system such as a battery, or connected to a public electricity network 50 Hz or 60 Hz. In the latter case, the DC direct current output of the solar panels is connected to a network inverter ("grid inverter") which generates a sinusoidal current of fixed frequency 50 or 60Hz at a voltage corresponding to the mains voltage (for example 230 VAC, 1 10 VAC). The sinusoidal current thus generated can be consumed by any machine connected to the domestic electrical network. However, a disadvantage of the conversion of the solar panel current by a grid-connected inverter is on the one hand the loss of conversion energy from the DC current to the sinusoidal alternating current and the relatively high cost of the grid inverters because the we seek to generate a sinusoidal alternating current. In JP 2010088276, a solar energy recovery system connected to a heat pump system is described. In order to take into account the variations of electrical power supplied by the solar panels, the power supply of the heat pump system also comprises a power supply of the electrical network. AC grid power is converted to DC direct current by an AC-DC converter and each current source - the grid, the solar panel, or a battery - are each connected to an inverter to generate a sinusoidal current to power the heat pump system. Different inverters are controlled by a controller connected to a voltmeter at the output of the solar panels to vary the power between each source depending on the available solar power. A disadvantage of this system is the high cost of providing an inverter for each power source and the controller to control the output of the different inverters, and also power losses related to this system of conversion and interconnection between several power sources. . Indeed, in this system as in conventional systems, we seek to recreate a sinusoidal wave for the power of the motors of the heat pump. An object of the invention is to provide a renewable energy generation system which is economical to install and use and which has a large relationship between the renewable energy generated and the non-renewable energy used for its generation.

One of the specific objects of the invention is to provide a geothermal energy recovery system which is very economical to install and use and which is very efficient in order to allow a low consumption of electrical energy from the public network.

The objects of the invention are realized by the renewable energy recovery system according to claim 1 or 2. In the present there is described a renewable energy recovery system comprising at least one AC electric motor, one or several photovoltaic solar panels, and an AC-DC / DC electronic converter interconnected between the solar panels and the electric motor. The system comprises at least one frequency converter connected to a direct current output DC of the electronic converter AC-DC / DC and to the electric motor. The frequency converter is configured for direct power supply of the electric motor without a grid inverter being provided to convert the DC output of the photovoltaic solar panels. The frequency converter allows at the same time to control the electric motor.

In a specific embodiment of the invention, the renewable energy recovery system comprises a heat pump system with at least one electric motor for a compressor or a fluid circulation pump, one or more photovoltaic solar panels. , an electronic converter AC-DC / DC interconnected between the solar panels and the heat pump system, and at least one frequency converter connected to a current output DC continuous AC-DC / DC electronic converter and the electric motor configured for the supply and control of the speed and current of the electric motor. Advantageously, the frequency converter is used to control and supply voltage / current to the electric motor that drives the compressor or to the circulating pumps of the heat pump. The addition of photovoltaic solar energy arrives in the electric motor with little loss because it avoids the use of three-phase inverters to process the DC signal of the solar panels in the converter. The AC-DC / DC electronic converter of the invention is economical and very easy to achieve even for low power because it does not require any self or significant filter capacity since the frequency inverters are already equipped. For a small installation (<3kW) or medium power (<10kW), the compressor can have a three-phase electric motor and a 400V AC three-phase inverter and the circulators can have 230V AC single-phase electric motors with single-phase frequency converters or three-phase 230V AC. For a high power installation (> 10kW), the compressor and circulators can have 400V three-phase electric motors and inverters.

The heat pump system according to the invention may advantageously include an energy storage system comprising a thermal energy storage tank in order to be able to use the heat pump when the solar energy is sufficient to supply the electric motors.

The AC-DC / DC electronic converter comprises at least one input connected to the AC public grid and at least one DC input connected to the photovoltaic solar panels. The converter In addition, the AC-DC / DC electronics may include one or more low-voltage outputs, such as a 24-volt DC output, configured for the supply of sensors, valves, controllers and electronics or another 5, 10 or 12V output for sensors.

The AC - DC / DC electronic converter is configured to perform an AC - DC conversion which rectifies the voltage of the AC public network to a DC voltage higher than the mains voltage, and a DC - DC conversion of the DC voltage of the DC. photovoltaic panels in a voltage greater than the DC voltage DC of the public network after conversion, these two conversions providing two sources of current. Both current sources can be connected to a frequency converter power supply and connected in parallel via diodes for protection of the power supply. A difference between a network inverter and a frequency converter is that it allows to have a variable output frequency that ranges from 0 to 400Hz. The grid inverter has a fixed output at 50 or 60 Hz and aims to supply the public network (50Hz or 60Hz) with a substantially sinusoidal signal. The frequency converter advantageously has current control algorithms with respect to the frequency which makes it possible to produce the maximum torque in a motor with respect to the current (MTPA = Maximum Torque Per Ampere), which makes it possible to make the best use of the current of the photovoltaic panels that are a source of current. In contrast, the network inverter typically only has management to produce a 50 or 60Hz sinusoidal voltage.

Another important difference of the system according to the invention is the absence of LC filter at the output of the frequency converter because it is designed to feed directly reciprocating engines. Other objects and advantageous aspects of the invention will emerge from the claims, from the following detailed description of an embodiment and the accompanying drawings, in which: FIG. 1a is a schematic illustration of a system of FIG. geothermal energy recovery according to one embodiment of the invention, with a high-power photovoltaic solar installation (less than 3kW); Figure 1b is a schematic illustration of a geothermal energy recovery system according to one embodiment of the invention, with a medium power photovoltaic solar installation (3kW to 10kW); FIG. 1c is a schematic illustration of a geothermal energy recovery system according to one embodiment of the invention, with a high power photovoltaic solar installation (greater than 10kW); Figure 2 is a circuit diagram of an AC-DC / DC electronic converter according to one embodiment of the invention; Figure 3a is a schematic illustration of an electric motor of a heat pump compressor of a geothermal energy recovery system according to one embodiment of the invention; Figure 3b is a schematic illustration of a power supply of a frequency converter and its connections to a solar panel according to one embodiment of the invention; Figure 4 is a diagram illustrating the operating principle of a frequency converter; Figure 5a is a graphical illustration of the waveform at the output of a frequency converter and Figure 5b is a graph of the relationship between motor voltage and motor speed of the frequency converter; FIG. 6a is a graphical illustration of the electric current supplied by a 175W solar photovoltaic panel as a function of the open circuit voltage for different sunshine values, and FIG. 6b is a graphical illustration of the open circuit voltage, respectively of short-circuit current of a 175W solar photovoltaic panel depending on the amount of sunshine (in W / m ² ).

Referring to the figures, a geothermal and solar energy recovery system 1 according to embodiments of the invention comprises a heat pump system 2, one or more photovoltaic solar panels 3, an electronic converter AC-DC / DC 4 interconnected between the solar panels and the heat pump system, geothermal probes 6, and optionally an energy storage system 5. The heat pump system 2 is fluidly connected to the geothermal probes for recovering energy thermal energy of the soil or air and provide this energy to one or more users of thermal energy 7, such as buildings, swimming pools or other constructions. The principle of recovery and supply of energy by a heat pump system is in itself well known and will not be described in detail. One or more temperature probes may be connected to a controller 35 of the heat pump system 2 for controlling the heating and storage circuits, including the valves of its circuits, depending on the outside and / or indoor temperature and the parameters defined by the users. The thermal energy produced can therefore be stored or used directly according to the needs and the surrounding temperature. Between 30 and 50% of the energy supplied by a conventional heat pump system comes from the electricity grid, this energy being necessary for the fluid circulation pumps through the heat exchanger and in the geothermal probes, and especially for the operation of the compressor of the heat pump. The regulation of the energy supplied to the user by a conventional heat pump is performed by the engagement and tripping of the system, the switching time regulating the amount of heat energy supplied. The electric motors of the compressor and conventional circulation pumps therefore have a very simple control system of the switch type for switching on and off the motors. In conventional systems, the electric motors are connected to the urban electricity network (in Europe alternating current 50 Hz and 230 Volts single-phase, 400 Volts three-phase). In conventional heat pump systems, engines run at constant, non-variable speeds. Conventional heat pump systems have no storage system and this would not make sense since there would be no benefit in storing energy in a conventional heat pump system.

The heat pump comprises a fluid circuit passing through a heat exchanger 8 and the geothermal probe 6, the circuit comprising a cold circuit portion 10 and a hot circuit portion 12. The heat pump may comprise a single fluid circuit, or two fluid circuits separated by the heat exchanger.

For the circulation of the fluid in the circuit or circuits, the heat pump system comprises one, two or more circulators 18a, 18b comprising fluid pumps driven by electric motors 15 '. The compressor 14 also comprises an electric motor 15, typically of greater power than the electric motors of the circulators.

The circulator and the compressor of the system according to the invention are advantageously supplied and controlled by frequency converters 16, 16 ', these frequency converters being connected to the current voltage outputs. continuous 24, 25 of the electronic converter 4. The electronic converter 4 has DC inputs 23 connected to the photovoltaic solar panels 3 and also has inputs 21, 22 for AC of the three-phase (400 Vac) and single-phase (230 Vac). The electronic converter 4 can advantageously also include a low-voltage output, such as a 24-volt DC output for the supply of sensors, valves, controllers and electronics. An advantageous embodiment of the converter circuit is illustrated in FIG. 2. The electronic converter 4 according to the invention advantageously makes it possible to directly connect the solar panels as well as the public electricity grid to the electric motors, by managing the contribution of the sources of electrical energy depending on the sun, and also allowing a control of the motors by the variable frequency drives, for an optimal use of the solar energy in a very economic configuration.

The configuration of the electronic converter may depend on the electrical power of the photovoltaic solar panels 3, as illustrated by Figures 1a, 1b and 1c summarized below by way of illustration:

Figure 1a: Small Power Installation - Solar Photovoltaic Panels Less than 3kW

 The electronic converter AC-DC / DC 4, which makes it possible to supply DC power to the frequency converter 16 by its three-phase input or by a DC bus if available, has the following characteristics:

^■ A 21, 22 three-phase 400VAC / 230VAC input connected to the public electricity grid

^■ A DC 23 voltage input from 150V DC to 250V DC connected to photovoltaic solar panels

■ A voltage output 24 from 550V DC to 800V DC connected to the frequency converter 16 of the compressor 14 ^■ A voltage output of 350V DC at 450V DC connected to the frequency converter 16 'of circulators 18a, 18b

^■ A 24V DC voltage output for the supply of valves, controllers, and electronics

 ■ 0-10V DC / DC analog output for measuring network power

^■ 0-10V analog output for solar power measurement

^■ Three-phase power 1 to 10kW

 The compressor has a three-phase electric motor and a 400V AC three-phase 16 drive and the circulators 18a, 18b have single-phase 230V AC electric motors with 16 'single-phase or three-phase 230V AC frequency inverters.

Figure 1b: Medium Power Plant - Photovoltaic Solar Panels from 3 to 10kW

 The electronic converter AC-DC / DC 4, which makes it possible to supply DC power to the frequency converter 16 by its three-phase input or by a DC bus if available, has the following characteristics:

^■ A 21, 22 three-phase 400VAC / 230VAC input connected to the public electricity grid

^■ A DC 23 voltage input from 600V DC to 800V DC connected to photovoltaic solar panels

^■ A voltage output 24 from 600V DC to 800V DC connected to the frequency converter 16 of the compressor 14

^■ A voltage output of 350V DC at 450V DC connected to the frequency converter 16 'of circulators 18a, 18b

 ■ A 24V DC voltage output for the supply of valves, controllers, and electronics

^■ 0-10V DC / DC analog output for measuring network power

^■ 0-10V analog output for solar power measurement

^■ Three phase power 3 to 30kW The compressor has a three-phase electric motor and a 400V AC three-phase 16 drive and the circulators 18a, 18b have single-phase 230V AC electric motors with 16 'single-phase or three-phase 230V AC frequency inverters. Figure 1c: Large Power Plant - Photovoltaic Solar Panels from 10kW to 100kW

 The electronic converter AC-DC / DC 4, which makes it possible to supply DC power to the frequency converter 16 by its three-phase input or by a DC bus if available, has the following characteristics:

 ■ A 21, 22 three-phase 400VAC / 230VAC input connected to the public electricity grid

^■ A DC 23 voltage input from 600V DC to 800V DC connected to photovoltaic solar panels

^■ A voltage output 24 from 600V DC to 800V DC connected to the frequency converter 16 of the compressor 14 and to the frequency converter 16 'of the circulators 18a, 18b

^■ A 24V DC voltage output for the supply of valves, controllers, and electronics

^■ Analog DC / DC 0-10V output for measuring mains power ■ Analog 0-10V output for measuring solar power

^■ Three-phase power 10 to 300kW

 The compressor has a three-phase electric motor and a four-phase 400V AC 16 drive and the circulators 18a, 18b have three-phase 400V AC 15 'electric motors with 16' three-phase 400V AC frequency inverters.

Principle of operation

The heat pump system 2 integrates the electronic converter AC-DC / DC 4 and an electronic controller or control in combination with one or more frequency inverters 16, 16 'which make it possible to manage the heating or cooling power as a function of available photovoltaic solar energy and user needs. The electronic converter AC-DC / DC 4 (see FIGS. 1 a-1c and 2) is configured to perform two types of conversion, an AC DC to DC direct current conversion which rectifies the AC 400V AC and 230V AC rectifier network into a DC voltage of 540V DC and 310V DC and a direct current conversion DC - DC DC which is the transformation of the DC voltage DC photovoltaic panels 3 into a slightly higher voltage (for example from 5 to 30%, for example d about 15%) to the DC voltage DC of the 400V AC / 230V AC public networks after conversion.

These two current sources are connected to a power supply 34 of the frequency converter 16, 16 '(see FIGS. 3a and 3b) and placed in parallel via protection diodes D1, D2 of the power supply and, consequently, it is ensured an isolation of the two sources of current. The equilibrium point (identical voltage of the two sources) must be reached when one is at the point of maximum power of the photovoltaic solar panels. Consideration is also given to the higher tolerance of the public electricity grid.

If the power from photovoltaic solar panels is insufficient to power the heat pump, the voltage will drop due to the high impedance of photovoltaic solar panels that operate as power sources, and then the supply of electrical energy comes from of the power grid because of its lower impedance. The transformation of the contribution of the electrical energy between the public network and the solar panels is therefore operated automatically according to the power from the solar panels. The DC voltage of the electronic converter 4 thus obtained is advantageously used directly for supplying the frequency converter 16, 16 'with its three-phase or single-phase power supply or with its DC bus, if available. On the three-phase frequency inverters, it is possible to connect to the DC output 24, 25 of the electronic converter 4 only two phases L1, L2 (see FIGS. 2, 3a) of the power supply 34 of the frequency converter 16, 16 '. This configuration according to the invention advantageously makes it possible to use the capacitance of filtering, accumulating and regulating the frequency converter because it contains capacitors of high capacity under a high DC voltage (> 540V DC), and the winding the electric motor 15, 15 'can advantageously be used as a smoothing choke.

The electronic converter AC-DC / DC 4 of the invention is therefore low cost and very easy to achieve even for low power of 1-2 kilowatts because, advantageously, it does not require self and significant filtering capabilities since frequency converters 16, 16 'are already provided.

The addition of photovoltaic solar energy arrives in the electric motor with little loss because it avoids the use of three-phase inverters to process the DC signal of the solar panels in the converter.

The regulator of the frequency converter controls and supplies voltage / current to the electric motor 15 which drives the compressor 14 of the heat pump 2 according to the data sent by the controller 36 of the heat pump.

The controller 36 of the heat pump will adapt the heating or cooling power according to the available electric solar energy and the needs of the user.

If the intake of the sun is too great, it is possible to store the energy produced by the heat pump in a storage tank 30 sized according to the power of the heat pump and the power of photovoltaic solar panels. This energy can then be used later in the day or at night, operating in both heating and cooling modes. According to an advantageous mode of operation of the invention, in cooling mode the heat produced can be sent into the geothermal probes 6 to store this energy in the ground. We will obtain a higher annual yield of the system.

According to the invention, the regulation of the heat pump makes it possible to optimize the utilization factor of solar energy, ideally close to 100%, without having the need to inject solar electricity into the public network.

Winter operation

 In winter, the geothermal heat pump can heat homes and sanitary water, the electricity required for its operation mainly from the 230V single-phase or 400V three-phase public network. If sunshine allows it, an electrical supply of photovoltaic solar panels can reduce the consumption on the public network.

The controller of the heat pump calculates in real time the power available by photovoltaic solar panels and adapts its heating power to obtain the best ratio energy network / solar energy.

The heat pump according to the invention can advantageously operate continuously during the day by avoiding a start / stop function of conventional heat pumps, which allows to obtain a good performance.

If the solar input is too important, one can heat a complementary storage tank 30 which can store this energy to restore it at the end of the day and enjoy the electricity network at night which is cheaper. If there is not enough sun, the heat pump can draw its electricity from the public grid. Spring operation

 Photovoltaic solar input is more important than in winter and the need for less heat energy, and therefore the heat pump will be able to operate almost only with solar energy.

The surplus during the day can be stored in a storage balloon 30 and returned overnight. Summer operation

 As solar input is at a maximum and heat requirements are reduced except for hot water, the heat pump can operate in cooling mode using only solar photovoltaic energy. Cold storage can be done in a water storage tank that will be used as requested. The heat that is generated can advantageously be sent to the geothermal probes and the soil can be used to store thermal energy. This stored energy can be used especially in autumn, and even in winter.

Operation in autumn

Similar to spring, but the yield will be higher because we can recover some of the energy sent into the ground in summer.

Stand-by operation

 When the heat pump is off, the electronics can still be powered by photovoltaic solar panels via electronic converter AC-DC / DC during the day even if the sun is not present. This optimizes the use of photovoltaic solar panels.

Frequency inverter wiring with three-phase motor

The frequency converter is used to convert the DC voltage of the solar photovoltaic converter into a usable three-phase AC voltage directly by a three-phase electric motor with speed and current control, as illustrated by the graphs in Figure 5a, 5b. The electric motor drives the compressor 14 of the heat pump as well as the circulation pumps P1, P2 for heating and geothermal probes 6. The frequency converter 16, 16 'contains capacitors of high capacity which allow to store sufficiently of energy to produce the current peaks needed by the motor.

The invention combines photovoltaic solar panels with a frequency converter on the market, and makes it possible to use the controller 36 of the frequency converter 16 to generate a three-phase AC voltage with a control of the speed and the current of the electric motor 15, 15 .

Referring to FIGS. 1 a-1c and 4, the heat pump controller 36 sends the speed reference to the frequency converter 16,16 ', 16 "according to several parameters such as:

^■ Heating or cooling power required

^■ Solar power available

^■ Power consumed on the public network

 ■ COP (coefficient of performance of the heat pump)

configured to produce the maximum energy through the heat pump using at least the energy of the public grid but at the maximum solar energy.

Connection to the frequency converter

The power supply 34 of the frequency converter 16, 16 'is via these connection terminals normally used for connection to 400VAC / 50Hz three-phase networks (Europe). The electronic converter 4 produces a DC voltage, and therefore only two terminals L1, L2 are used to supply the frequency converter (L1 = + V, L2 = -V). Referring to Figure 3, the bridge of six diodes D1, D2 passes the current in the direction of the arrows, so there is no short circuit. These diodes are sized for withstands reverse voltages of 1000V DC, which allows operation of the solar controller with a voltage up to 800V DC.

Features of photovoltaic solar panels

Referring to Figs. 6a and 6b, a photovoltaic solar panel produces a current as a function of sunlight in a substantially proportional manner. The maximum power depending on the sunshine is almost always available with the same output voltage, the difference being about 10%. In addition, this power remains essentially constant in the same voltage range, which facilitates the construction of the electronic converter 4 and its DC-DC conversion.

Example solar panels of 175W

 Converter A C-DC / DC

According to one embodiment, the converter uses PWM technology in push-pull mode at an average frequency of 100 kHz for DC / DC conversion. This frequency is a good compromise because it allows the use of standard electronic components. The transformer may for example be Ferroxcube type ETD59 with losses at a frequency of 150Khz which are not too high. The sizing of the transformer is optimized according to the voltage / current characteristics of the photovoltaic solar panels, to reach a duty cycle of about 49% to obtain the maximum power of the transformer. Overvoltage protection may be provided when the DC voltage of the converter exceeds 800V DC, since the capacitors of the 400VAC / 50Hz three-phase frequency converters on the market have a maximum operating voltage of 800VDC. For a power higher than 2kW, the AC-DC / DC electronic converter can be configured to provide only the low power conversions for supplying the circulating pumps as well as the controller of the heat pump.

The controller of the heat pump The controller of the heat pump 36 may be of industrial current type such as the Saia PCD1 m, having enough analog inputs to better analyze the needs, the efficiency and the energy productivity, such as:

^■ Measurement of electrical power absorbed on the public network

^■ Measurement of electric power produced by solar panels

^■ Heat output measurement of the heat pump

^■ External temperature measurement.

^■ Internal temperature measurement of the house

^■ DHW temperature measurement (Sanitary hot water)

^■ Heating flow temperature measurement

^■ Heating return temperature measurement

^■ Heating water flow measurement

^■ Evaporator flow temperature measurement

^■ Evaporator return temperature measurement

The advantageous combination of solar panels and a frequency converter with an electronic converter for connecting the two according to the invention can be used in other applications than the heat pump, for example in ventilation systems of a building. , or for industrial production systems using thermal energy. Advantageously, the invention makes it possible, without significant modification, to connect frequency converters available on the market on photovoltaic solar panels without the need to use a three-phase inverter. Three-phase electric motors have a very good efficiency, so it is very advantageous to use this solar energy through frequency inverters. List of elements referenced in the figures

 1 geothermal and solar energy recovery system

 2 heat pump

 8 heat exchanger

 10 cold circuit

 12 hot circuit

 14 compressor

 15 electric motor

 16 frequency converter

 34 inverter supply

 18a, 18b circulators

 15 'electric motor

 16 'frequency inverter

 34 inverter supply

 35 controller

 36 external temperature probe

3 photovoltaic solar panels

 23 DC output

 4 AC-DC / DC electronic converter

 21 AC 400V AC three-phase input

 22 single-phase 230V AC mains input

 23 input connection photovoltaic panels150-250V DC

24 DC output - 550-800V DC

 25 DC output - 300-500V DC

 26 DC output - 24V DC

5 energy storage system

 28 valve

 30 storage tank

 32 circuits

 6 geothermal probes

7 thermal energy user

Claims

claims 1. Renewable energy recovery system (1) comprising at least one electric motor (16, 16) for a compressor (14) or a fluid circulation pump (18a, 18b) of a heat pump system (2) , one or more photovoltaic solar panels (3), and an electronic converter (4) AC-DC / DC comprising at least one input (21, 22) configured to be connected to an AC power source, in particular a public electricity network alternating, and at least one DC input (23) connected to one or more photovoltaic solar panels, characterized in that the system further comprises at least one frequency converter (16, 16 ') connected to a direct current output DC (24, 25) of the converter and at least one electric motor, the frequency converter configured for the direct supply of said at least one electric motor without grid inverter and for the control of the electric motor. 2. A renewable energy recovery system (1) comprising a heat pump system (2) with at least one electric motor (16, 16 ') for a compressor (14) or a fluid circulation pump (18a, 18b), one or more photovoltaic solar panels (3), and an electronic converter (4) AC-DC / DC interconnected between the solar panels and the heat pump system, the AC-DC / DC electronic converter comprising at least one input (21, 22) configured to be connected to an alternating current source AC, in particular an alternative public electrical network, characterized in that the electronic converter (4) AC-DC / DC is interconnected between the solar panels and the control system. heat pump without grid inverter, and in that the system comprises at least one frequency converter (16, 16 ') connected to a direct current output DC (24, 25) of the converter and at least one electric motor for direct supply and control of said at least one electric motor. 3. System according to claim 2, characterized in that the heat pump system comprises several AC electric motors for the compressor and the fluid circulation pump or pumps (18a, 18b), each of the electric motors being directly connected to a frequency converter (16, 16 '), each frequency converter being connected to a DC voltage output (24, 25) of the electronic converter (4). 4. System according to claim 3 characterized in that the compressor has a three-phase electric motor and a three-phase inverter 400V AC and circulators have 230V AC single-phase electric motors with single-phase or three-phase 230V AC frequency inverters. 5. System according to claim 3 characterized in that the compressor and the circulators have electric motors and three-phase inverters 400V. 6. System according to one of claims 1 to 5, characterized in that it includes an energy storage system (5) comprising a storage tank (30) of thermal energy. 7. System according to one of the preceding claims, characterized in that the electronic converter (4) AC-DC / DC comprises a low voltage output, such as a 24 VDC output, configured for the supply of sensors , valves, automata and electronics. 8. System according to one of the preceding claims, characterized in that the AC-DC / DC electronic converter is configured to perform an AC-DC conversion which rectifies the voltage of the alternative public network into a DC voltage of higher value than the mains voltage, and a DC-DC conversion of the DC voltage of the photovoltaic panels to a voltage greater than the DC voltage DC of the public network after conversion, these two conversions providing two sources current. 9. System according to one of the preceding claims, characterized in that the AC-DC / DC electronic converter is configured to perform a conversion AC - DC which rectifies the voltage of the AC public network in a DC voltage of 540V DC and 310V DC. and a DC-DC conversion of the DC voltage DC of the photovoltaic panels (3) to a voltage 5% to 30% higher than the DC voltage DC of the public networks 400V AC / 230V AC after conversion 10. System according to claim 8 or 9, characterized in that the two current sources are connected to a power supply (34) of the frequency converter and connected in parallel via protective diodes D1, D2 of the power supply. 1 1. System according to one of the preceding claims, characterized in that the electronic converter (4) AC-DC / DC uses PWM technology in push-pull mode at an average frequency of 100kHz for DC / DC conversion. 12. System according to one of the preceding claims, characterized in that the electronic converter (4) AC-DC / DC comprises a transformer configured according to the voltage / current characteristics of photovoltaic solar panels to achieve a duty cycle of about 49%. 13. System according to one of the preceding claims, characterized in that the electronic converter (4) AC-DC / DC comprises a protection against overvoltage when the DC voltage of the converter exceeds 800V DC. 14. System according to claim 1, 2, 3 or 4 for photovoltaic solar panels of less than 3kW, characterized in that the AC-DC / DC electronic converter comprises: ^■ a three-phase input (21, 22) 400VAC / 230VAC connected to the public electricity grid ^■ a DC voltage input (23) from 150V DC to 250V DC connected to photovoltaic solar panels ^■ a voltage output (24) of 550V DC at 800V DC connected to the frequency converter (16) of the compressor (14) ^■ a voltage output (25) of 350V DC at 450V DC connected to the frequency converter (16 ') of the circulators (18a, 18b) ^■ a 24V DC voltage output for the supply of valves, controllers and electronics ^■ 0-10V DC / DC analog output for measuring network power ^■ a 0-10V analogue output for measuring solar power 15. System according to claim 1, 2, 3 or 4 for photovoltaic solar panels of 3 to 10 kW, characterized in that the AC-DC / DC electronic converter comprises: ^■ a three-phase input (21, 22) 400VAC / 230VAC connected to the public electricity grid ^■ a DC voltage input (23) from 600V DC to 800V DC connected to photovoltaic solar panels ^■ a voltage output (24) of 600V DC at 800V DC connected to the frequency converter (16) of the compressor (14) ^■ a voltage output (25) of 350V DC at 450V DC connected to the frequency converter (16 ') of the circulators (18a, 18b) ^■ a 24V DC voltage output for the supply of valves, controllers and electronics ^■ 0-10V DC / DC analog output for measuring network power ^■ a 0-10V analogue output for measuring solar power 16. System according to claim 1, 2, 3 or 5 for photovoltaic solar panels of more than 10 kW, characterized in that the AC-DC / DC electronic converter comprises: ^■ a three-phase input (21, 22) 400VAC / 230VAC connected to the public electricity grid ^■ a DC voltage input (23) from 600V DC to 800V DC connected to photovoltaic solar panels ^■ a voltage output (24) of 600V DC at 800V DC connected to the frequency converter (16) of the compressor (14) and to the frequency converter (16 ') of the circulators (18a, 18b) ^■ a 24V DC voltage output for the supply of valves, controllers and electronics ^■ 0-10V DC / DC analog output for measuring network power ^■ a 0-10V analogue output for measuring solar power