JPH0669638U - Air conditioner - Google Patents

Abstract

(57) [Abstract] [Purpose] The current value of the compressor 1 is measured and the frequency is controlled by the optimum voltage. [Composition] A compressor 1, a condenser 3.5, an expansion mechanism 4, and an evaporator 3.5 are sequentially connected, and a frequency / voltage control unit 11 for controlling the frequency and voltage to the compressor 1 is connected. The frequency of the power supply output by the frequency / voltage control unit 11 to the compressor 1 is set to the compressor 1 based on the air conditioning load.
In the air conditioner for controlling the capacity of the compressor 1, a current detector 12 for detecting the current of the compressor 1 is provided, and the frequency / voltage controller 11 outputs a frequency according to an air conditioning load to the compressor 1. The operating efficiency of the compressor 1 can be improved by providing the voltage correction unit 14 that controls the supply voltage and corrects the supply voltage according to the current value detected by the current detection unit 12.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an air conditioner including a compressor whose rotation speed changes depending on the magnitude of an air conditioning load.

[0002]

[Prior art]

 In recent years, in a home air conditioner, a capacity control method has been adopted in which a frequency / voltage control unit controls an operating frequency of a compressor in order to cope with an increase or decrease in an air conditioning load. An air conditioner adopting this method will be described with reference to FIG. 5. 1 is a compressor, 2 is a four-way valve for switching the heating / cooling cycle, 3 is an outdoor heat exchanger that acts as a condenser during cooling, and 4 is The expansion valve, 5 is an indoor heat exchanger that functions as an evaporator during cooling, and 6 is an accumulator, which are connected in a ring to form a refrigeration cycle.

Reference numeral 7 is a temperature sensor for detecting the room temperature, 8 is a set temperature control means for controlling the set value of the room temperature, and 9 is a room temperature / set temperature comparison unit for comparing the difference between these two temperatures. A frequency setting unit 10 determines the operating frequency of the compressor 1 based on this difference. A frequency / voltage control unit 11 controls the operating frequency and voltage. The operation of the air conditioner configured as above will be described. During the cooling operation, the high-temperature high-pressure refrigerant gas compressed by the compressor 1 passes through the four-way valve 2 and is condensed and liquefied by the outdoor heat exchanger 3. Further, the expansion valve 4 adiabatically expands into a low-temperature low-pressure gas-liquid two-phase refrigerant, which evaporates and gasifies in the indoor heat exchanger 5, reaches the accumulator 6, and returns to the compressor 1 to repeat the cycle.

During the heating operation, the high-temperature and high-pressure refrigerant gas compressed by the compressor 1 passes through the four-way valve and is condensed and liquefied by the indoor heat exchanger 5. Further, the expansion valve 4 adiabatically expands the refrigerant gas to a low temperature and low pressure. It becomes a gas-liquid two-phase refrigerant, evaporates and gasifies in the outdoor heat exchanger 3, reaches the accumulator 6, and returns to the compressor 1. The cycle is repeated. Then, as shown in FIG. 6, the operating frequency supplied to the compressor 1 was determined by the magnitude of the difference between the set temperature and the room temperature, and the compressor 1 was operated at a voltage corresponding to this frequency.

Further, as shown in Japanese Patent Laid-Open No. 64-79552, the temperatures of the heat exchangers 3.5 are measured, the load torque of the compressor 1 is calculated, and a large number of preset torques are calculated according to this value. It is possible to operate the compressor 1 with high efficiency by selecting a pattern close to the optimum Vf characteristic from the Vf characteristic (voltage / frequency characteristic: hereinafter referred to as Vf characteristic) pattern. Became.

[0006]

[Problems to be solved by the device]

 However, since the former air conditioner has only one V-f characteristic pattern in the frequency / voltage control unit, when the compressor 1 is actually operated with this V-f characteristic, it may depend on the operating conditions. Since the load torque applied to the compressor 1 is different, the voltage drop value is also different. For example, under cooling / heating overload conditions in which the indoor and outdoor air temperatures rise, the condensation temperature / evaporation temperature rises, so the load torque applied to the compressor 1 also increases and the voltage drop value also increases.

On the contrary, under cooling / heating low temperature conditions in which the indoor and outdoor air temperatures decrease, the condensing temperature / evaporating temperature also decreases, so the load torque applied to the compressor 1 decreases and the voltage drop also decreases. In other words, the operating voltage of the compressor 1 also fluctuates according to the fluctuation of the load torque, so that it deviates from the optimum operating voltage, and as a result, the input of the compressor 1 increases and the operating efficiency deteriorates.

Since the latter air conditioner calculates the load torque of the compressor 1 and selects the pattern that is closest to the optimum Vf characteristic pattern from the preset Vf characteristic pattern, the former air conditioner is selected. Compared with other air conditioners, the operating efficiency of the compressor 1 is improved, but the number of preset operation patterns is limited, and it is still necessary to improve in order to improve the operating efficiency. was.

[0009]

[Means for solving problems]

 This invention focuses on this point and solves the above-mentioned drawbacks. In particular, the configuration is such that a compressor, a condenser, an expansion mechanism and an evaporator are sequentially connected, and the frequency and voltage to the compressor are controlled. In an air conditioner that connects a frequency / voltage control unit and controls the frequency of the power supply output by the frequency / voltage control unit to the compressor based on the air conditioning load, the capacity of the compressor. A current detection unit that detects the current of the compressor is provided, and the frequency / voltage control unit outputs the frequency according to the air conditioning load to control the supply voltage to the compressor, and the current detected by the current detection unit. A voltage correction unit is provided to correct the supply voltage according to the value.

[0010]

[Action]

 In steps 20 and 21, the set temperature and room temperature are detected, and the values are output to step 22 to calculate the temperature difference between the room temperature and the set temperature. As a result, when the temperature difference Δt is smaller than the preset minimum temperature difference T min in step 23, the process proceeds to step 24 and the compressor 1 is stopped. If the temperature difference Δt is larger than the minimum temperature difference Tmin, the frequency is determined based on the temperature difference in step 25, and the frequency is controlled in step 26.

In step 27, it is determined whether the frequency is stable. If the frequency is fluctuating, the process returns to the frequency control in step 26, and if the frequency is stable, the process proceeds to step 28. In step 28, the operating current of the compressor 1 is detected, and the voltage correction in step 29 is proceeded to. The flow chart of FIG. 4 shows the method of voltage correction in step 29, and is to find the minimum value of the current such as point A in the graph of FIG. 2 (b). As described above, the voltage corresponding to one frequency has a width.

First, in step 30, the operating voltage is increased by 5%, and in step 31, the current value is compared with that in step 28. If the current value decreases, in step 32 the voltage is increased by 5% again to step 33. move on. In step 33, the current value is compared with the current value in step 31, and if the current value falls, the process returns to step 32, and this is repeated until the current value rises above the previously measured current value in step 33.

When the current value increases, the process proceeds to step 34, the voltage is reduced by 5%, and the proper voltage is determined. On the contrary, if the current is increased in step 31, the voltage is decreased by 5% in step 35, and the process proceeds to step 36. If the current value is decreased in step 36, the process returns to step 35. This is repeated until the current increases in step 36, and if the current turns to increase, the voltage is increased by 5% in step 37 to determine the optimum voltage.

[0014]

【Example】

 An air conditioner according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a cooling system diagram and a block diagram of the present invention, and the same parts as the cooling system diagram and the block diagram of the conventional example of FIG. 5 are designated by the same reference numerals. Since the cooling system is the same as the conventional example, the description of the configuration will be omitted and the configuration of the block diagram will be described. Reference numeral 7 is a temperature sensor for detecting the room temperature, 8 is a set temperature control unit for controlling the set value of the room temperature, and 9 is a room temperature / set temperature comparison unit for comparing the two temperatures.

Reference numeral 10 is a frequency setting unit that determines the operating frequency of the compressor 1 based on this temperature difference, and 11 is a frequency / voltage control unit that controls the operating frequency and voltage. Reference numeral 12 is a current detection unit for detecting the operating current of the compressor 1, which reads the value of the current sensor 13 provided on the lead wire connecting the compressor 1 and the frequency / voltage control unit 11, and the voltage correction unit 14 To send a signal to. The voltage correction unit 14 finely adjusts the voltage so that the voltage can be operated at the minimum operating current value at the frequency at that time.

Next, the frequency / voltage control method will be described with reference to the flowchart of FIG. 3. In steps 20 and 21, the set temperature and room temperature are detected, and the values are output to step 22. Calculate the temperature difference between room temperature and set temperature. As a result, when the temperature difference Δt is smaller than the preset minimum temperature difference T min in step 23, the process proceeds to step 24 and the compressor 1 is stopped. If the temperature difference Δt is larger than the minimum temperature difference Tmin, the frequency is determined based on the temperature difference in step 25, and the frequency is controlled in step 26.

In step 27, it is determined whether the frequency is stable. If the frequency is fluctuating, the process returns to the frequency control in step 26, and if the frequency is stable, the process proceeds to step 28. In step 28, the operating current of the compressor 1 is detected, and the voltage correction in step 29 is proceeded to.

The flow chart of FIG. 4 shows the method of voltage correction in step 29, and is for obtaining the minimum value of the current such as point A in the graph of FIG. 2 (b). As in a), the voltage corresponding to one frequency has a width. First, in step 30, the operating voltage is increased by 5%, and in step 31, the current value is compared with that in step 28. If the current value decreases, the voltage is increased by 5% again in step 32 and the process proceeds to step 33.

In step 33, the current value is compared with that in step 31, and if the current value falls, the process returns to step 32, and this is repeated until the current value rises above the previously measured current value in step 33. Then, when the current value has risen, the routine proceeds to step 34, where the voltage is reduced by 5% and the proper voltage is determined. On the contrary, if the current is increased in step 31, the voltage is decreased by 5% in step 35, and the process proceeds to step 36. If the current value is decreased in step 36, the process returns to step 35.

Until the current rises in step 36, this is repeated until the current rises. In step 37, the voltage is raised by 5% to determine the optimum voltage. By operating the compressor 1 at the optimum voltage and the minimum current value corresponding to the operating frequency, the compressor 1 is operated at the optimum voltage and the efficiency EER (capacity for input power) is improved.

[0021]

[Effect of device]

 As described above, according to the present invention, the compressor, the condenser, the expansion mechanism, and the evaporator are sequentially connected, and the frequency / voltage control unit for controlling the frequency and voltage to the compressor is connected, In the air conditioner that controls the capacity of the compressor based on the frequency of the power supply output to the compressor by the frequency / voltage control unit, the current detection unit that detects the current of the compressor The frequency / voltage control unit outputs a frequency according to the air conditioning load, controls the supply voltage to the compressor, and includes a voltage correction unit that corrects the supply voltage according to the current value detected by the current detection unit. Therefore, it was possible to operate the compressor with high efficiency and reduce power consumption.

[Brief description of drawings]

FIG. 1 is a refrigeration system diagram and a block diagram according to an embodiment of the present invention.

FIG. 2 is a relationship diagram of the same voltage-frequency and current-voltage.

FIG. 3 is the same flowchart.

FIG. 4 is a flowchart of the same voltage correction.

FIG. 5 is a conventional refrigeration system diagram and block diagram.

FIG. 6 is a voltage-frequency relationship diagram of the same.

[Explanation of symbols]

 1 Compressor 3 Outdoor Heat Exchanger 5 Indoor Heat Exchanger 7 Temperature Sensor 8 Setting Temperature Control Section 9 Room Temperature / Setting Temperature Comparison Section 10 Frequency Setting Section 11 Frequency / Voltage Control Section 12 Current Detection Section 13 Current Sensor 14 Voltage Correction Section

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Toyohisa Moriyama 7-7 Higashishinpo, Sanjo City, Niigata Prefecture Uchida Manufacturing Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A compressor, a condenser, an expansion mechanism, and an evaporator are sequentially connected to each other, and a frequency / voltage control unit for controlling the frequency and voltage to the compressor is connected to the frequency / voltage control unit. Is the frequency of the power supply output to the compressor,
In an air conditioner that controls the capacity of the compressor based on the air conditioning load, a current detection unit that detects the current of the compressor is provided, and the frequency / voltage control unit outputs a frequency according to the air conditioning load. An air conditioner comprising: a voltage correction unit that controls the supply voltage to the compressor and corrects the supply voltage according to the current value detected by the current detection unit.