CN103231663B - Low-cost driving system with three independent power supplies and for electromobile - Google Patents

Abstract

The invention provides a low-cost driving system with three independent power supplies and for an electromobile. The system comprises the three independent power supplies, three switch tubes, a three-phase double-salient driving motor, a control system and the like. The system is characterized in that the three-phase double-salient driving motor is powered up by the three independent power supplies, a bridge arm is formed by connecting each independent power supply and a corresponding switch tube in series, three bridge arms are sequentially connected in an end-to-end mode in series in a triangle shape, and three connection points of the bridge arms are connected with a three-phase star-like winding of the double-salient driving motor respectively. The pole-arc coefficient of a stator core of the three-phase double-salient driving motor is 0.5, and the pole-arc coefficient of a rotor core of the three-phase double-salient driving motor is 0.333. The system is few in switching elements, low in cost, free of three-phase inverter direction connection and high in reliability and has high practicability.

Description

A low-cost drive system for electric vehicles with three independent power supplies

technical field

The invention relates to a low-cost electric vehicle drive system with three independent power supplies, belonging to the technical field of electric vehicle drive.

Background technique

The drive system of electric vehicles often uses a three-phase bridge inverter, which uses 6 switching tubes, is expensive, has a high conduction voltage drop, and works under harsh conditions such as high temperature and high frequency. The weakest part of the drive system, the improper setting of the dead zone is very prone to through faults. Since reducing the number of switching tubes can effectively improve system reliability and reduce system cost, the market urgently needs to develop a driving system with fewer switching tubes and high reliability.

Double salient pole motor is a new type of motor composed of position sensor, power electronic power converter, permanent magnet or electromagnetic excitation unit, controller and motor body with salient pole stator and rotor structure. As a new type of variable reluctance motor, it has a large ratio between the maximum value and the minimum value of reluctance, and has good electromechanical energy conversion characteristics, and has a good application prospect in the electric vehicle industry.

Among the existing technologies, many invention patents describe three-phase motors using traditional three-phase bridge inverters. There are also some patents that have improved the traditional three-phase bridge inverter, such as the authorized invention patent: ZL201010565874.3, which is used for a three-leg nine-switch inverter driven by dual AC motors. One inverter controls two three-phase AC motors independently at the same time. Since the number of switching tubes in the inverter is 9, it is less than the traditional inverter with six switching tubes for each motor.

The new double-salient motor has a good application prospect in the electric vehicle industry, so there are also some domestic research results. The paper published in the 6th issue of "Journal of Electrotechnical Society" in 2008: Design and realization of a new stator double-fed doubly salient motor drive system for electric vehicles, designed an electrically excited doubly salient motor, and used digital signal processing The inverter realizes electric control; the Chinese invention patent with the application number of 200610097465.9: doubly salient motor driver, the attached drawing 1 discloses a three-phase bridge inverter circuit commonly used in three-phase doubly salient motors, the inverter It is consistent with the traditional three-phase inverter circuit. The Chinese invention patent with application number 201110062872.7: Four-phase double-salient pole motor discloses a four-phase inverter for a four-phase double-salient pole motor, which has one more bridge arm than the traditional three-phase inverter . Authorized invention patent: ZL200810021000.4, a fault-tolerant control method for doubly salient permanent magnet motors, invented a control method that uses three-phase square wave control during normal operation, and drives through equivalent sine waves during fault operation. The inverter used in the method is still the traditional three-phase bridge inverter.

The inverters used in the three-phase double-salient pole motors mentioned in the above documents are all three-phase bridge inverters. The inverter uses three upper switching tubes and three lower switching tubes to realize the commutation drive of the motor. There are many tubes, the voltage drop is large, and the loss is large; and it is also easy to have a direct phenomenon of the upper and lower switching tubes, which can easily cause damage to the power system.

Compared with the prior art, the low-cost three-independent power supply electric vehicle drive system disclosed in the present invention uses three independent power supplies and three switch tubes to supply power to the doubly salient drive motor, has fewer switching devices, and has a novel circuit topology and On this basis, a three-beat conduction control method suitable for controlling doubly salient motors is given.

At present, the low-cost electric vehicle drive system with three independent power sources proposed by the present invention has not been retrieved at home and abroad.

Contents of the invention

Combining the drive control mode of the three-phase double-salient pole motor, the present invention proposes a low-cost electric vehicle drive system with three independent power supplies. The system can build a three-phase double-salient pole motor by using only three switch tubes and three independent power supplies. The main power circuit has fewer switching devices, low cost, less switching tube loss and high reliability.

In order to reduce the cost and loss of the three-phase bridge inverter used in the traditional three-phase double-salient pole motor, the present invention adopts the following technical scheme:

A low-cost electric vehicle drive system with three independent power supplies, including three independent power supplies, three switch tubes, a three-phase double-salient drive motor, a position sensor, a current sensor and a control system, is characterized in that: the three-phase double-convex The polar drive motor is powered independently by the first independent power supply (U1), the second independent power supply (U2) and the third independent power supply (U3), and the first independent power supply (U1) and the first switching tube (Q1) are connected in series. The first bridge arm, the second independent power supply (U2) and the second switch tube (Q2) are connected in series to form the second bridge arm, and the third independent power supply (U3) and the third switch tube (Q3) are connected in series to form the third bridge arm. The two bridge arms are connected in series head to tail in sequence in a triangle connection manner, and the first switch tube (Q1), the second switch tube (Q2) and the third switch tube (Q3) are respectively connected in parallel with a first body diode (D1), a second body diode ( D2) and a third body diode (D3); the three-phase double salient pole drive motor is composed of a three-phase winding, a salient pole stator core, a salient pole rotor core and a shell, one end of the A-phase winding and the first bridge arm Connected to the connection point of the second bridge arm, one end of the B-phase winding is connected to the connection point of the second bridge arm and the third bridge arm, one end of the C-phase winding is connected to the connection point of the third bridge arm and the first bridge arm, The other end of the three-phase winding is connected together to form a three-phase star winding. The pole arc coefficient of the stator core is 1/2, and the pole arc coefficient of the rotor core is 1/3. The three-phase double salient pole drive motor can be used The field winding is excited, and the permanent magnet can also be used for excitation; the position sensor is used to detect the rotor position, and the control system controls the first switching tube (Q1), the second switching tube (Q2) and the third switching tube (Q3) according to the detected position signal ) is turned on or off; when the A-phase inductance rises and the C-phase inductance drops, the first switching tube (Q1) is controlled to conduct a positive current to the A-phase winding, and a negative current to the C-phase winding, and the A-phase winding and the C-phase winding The phase windings work together; when the B-phase inductance rises and the A-phase inductance drops, the second switching tube (Q2) is controlled to conduct a positive current to the B-phase winding and a negative current to the A-phase winding, and the B-phase winding and the A-phase The windings work together; when the C-phase inductance rises and the B-phase inductance decreases, the third switching tube (Q3) is controlled to conduct a positive current to the C-phase winding, and a negative current to the B-phase winding, and the C-phase winding and the B-phase winding Common output; the current sensor is used to detect the current and send the signal to the control system to limit the current and protect the circuit; the control system receives the sensor, throttle and brake signals, and after conditioning the sensor, throttle and brake signals, the sensor, throttle and and brake signals are sent to the control unit, and the control unit outputs the driving signal of the switching tube after calculation, and the signal is sent to the first switching tube (Q1), the second switching tube (Q2) and the third switching tube respectively after passing through the driving isolation circuit Tube (Q3) to realize the control of the system.

The beneficial effects of the present invention are as follows:

1 Three independent power supplies and three switching tubes are used to supply power to the doubly salient drive motor, with fewer switching devices, low cost, and less switching tube loss; 3. The three-phase drive motor of the electric vehicle adopts a three-phase double-salient pole motor. This machine can provide a magnetic field by the permanent magnet on the stator or the excitation winding. The rotor structure is simple, realizing the motor Brushless, high reliability, can run at high speed and harsh conditions; 4. Adopt three-beat conduction control method to control the rotation of the doubly salient motor, which can effectively play the characteristics of the doubly salient motor.

According to the law of energy conservation, although the system uses three independent power supplies for power supply, the total capacity of the three power supplies is still the capacity of one power supply in the traditional drive system, which will not increase the cost of the power supply system.

Description of drawings

Fig. 1 is a composition diagram of the low-cost three independent power supply electric vehicle drive system of the present invention.

Fig. 2 is a structural schematic diagram of a three-phase electric excitation doubly salient drive motor of the low-cost three independent power supply electric vehicle drive system of the present invention. Among them, 1. Field winding; 2. Armature winding; 3. Stator core; 4. Rotor core.

Fig. 3 is a structural schematic diagram of the three-phase tangential permanent magnet double salient drive motor of the low-cost three independent power supply electric vehicle drive system of the present invention. 1. Permanent magnet; 2. Armature winding; 3. Stator core; 4. Rotor core.

Fig. 4 is a structural schematic diagram of the three-phase radial permanent magnet double salient pole driving motor of the low-cost three independent power supply electric vehicle drive system of the present invention. 1. Armature winding; 2. Stator core; 3. Motor shell; 4. Permanent magnet; 5. Rotor core.

Fig. 5 is a schematic diagram of the three-step conduction control of the low-cost three independent power supply electric vehicle drive system of the present invention.

Fig. 6 is a connection diagram of a traditional three-phase motor and a three-phase bridge inverter.

Detailed ways

The invention will be described in further detail below in conjunction with the accompanying drawings.

Fig. 1 is a composition diagram of the low-cost three independent power supply electric vehicle drive system of the present invention. The system includes three independent power supplies, three switch tubes, a three-phase double salient drive motor, a position sensor, a current sensor and a control system, and is characterized in that: the three-phase double salient drive motor is composed of U1, U2 and U3 The first independent power supply (U1) and the first switching tube (Q1) are connected in series to form the first bridge arm, and the second independent power supply (U2) and the second switching tube (Q2) are connected in series to form the second bridge arm. Three independent power supplies (U3) and the third switching tube (Q3) are connected in series to form the third bridge arm, and the three bridge arms are connected in a triangle connection in order from end to end in series, the first switching tube (Q1), the second switching tube (Q2) and the second switching tube (Q2) The three switch tubes (Q3) are respectively connected in parallel with a first body diode (D1), a second body diode (D2) and a third body diode (D3); Composed of stator core, salient pole rotor core and casing, one end of A-phase winding is connected to the connection point of the first bridge arm and the second bridge arm, one end of B-phase winding is connected to the connection point of the second bridge arm and the third bridge arm One end of the C-phase winding is connected to the connection point between the third bridge arm and the first bridge arm, and the other end of the three-phase winding is connected together to form a three-phase star winding. The position sensor is used to detect the position of the rotor, and the control system controls the three switch tubes to be turned on or off according to the detected position signal to realize the rotation of the motor. Current sensors are used to detect current and send signals to control systems to limit current and protect circuits. The control system receives the sensor, accelerator and brake signals, and sends the sensor, accelerator and brake signals to the control unit after adjusting the sensor, accelerator and brake signals. The control unit outputs the drive signal of the switch tube after calculation, and the signal passes through After the isolation circuit is driven, the signals are respectively sent to the first switching tube (Q1), the second switching tube (Q2) and the third switching tube (Q3) to realize the control of the system.

Fig. 2 is the structural representation of the three-phase electric excitation double salient pole driving motor of the low-cost three independent power supply electric vehicle drive system of the present invention, the pole arc coefficient of the stator iron core of this machine is 1/2, and the pole arc coefficient of the rotor iron core is 1/2 3.

Fig. 3 is the three-phase tangential permanent magnet doubly salient drive motor structure schematic diagram of the low-cost three independent power supply electric vehicle drive system of the present invention, the magnetization direction of this machine permanent magnet is tangential, and the pole arc coefficient of its stator core is 1/2, and the pole arc coefficient of the rotor core is 1/3.

Fig. 4 is the structural representation of the three-phase radial permanent magnet double salient pole drive motor of the low-cost three independent power supply electric vehicle drive system of the present invention, the magnetization direction of this machine permanent magnet is radial direction, and the pole arc coefficient of its stator core is 1/2, and the pole arc coefficient of the rotor core is 1/3.

Similarly, this system can also use a doubly salient motor with mixed excitation of permanent magnet and electric excitation as the drive motor.

Fig. 5 is a schematic diagram of the three-step conduction control of the low-cost three independent power supply electric vehicle drive system of the present invention.

Fig. 6 is a connection diagram of a traditional three-phase motor and a three-phase bridge inverter.

It can be seen from Figure 6 that when a traditional three-phase motor is matched with a traditional three-phase bridge inverter, a total of six switching tubes are required. Taking the commonly used Mitsubishi PM100RSE120 as an example, its price is about 1800 yuan. Therefore, saving three switch tubes can save a lot of system cost.

Combining with Figure 5, it can be seen that the working principle of this system is that when the electrical angle is between (0°, 120°), the A-phase inductance rises and the C-phase inductance decreases, and at this time the control switch (Q1) is turned on to give A-phase winding passes positive current, and C-phase winding passes negative current. The reluctance torques of A-phase winding and C-phase winding cancel each other out. A-phase winding outputs positive electromagnetic torque Taf, and C-phase winding outputs positive electromagnetic torque. The torque Tcf, the A-phase winding and the C-phase winding work together; when the electrical angle is between (120°, 240°), when the B-phase inductance increases and the A-phase inductance decreases, the control switch (Q2) is turned on at this time Pass a positive current to the B-phase winding, pass a negative current to the A-phase winding, the reluctance torques of the B-phase winding and the A-phase winding cancel each other out, the B-phase winding outputs a positive electromagnetic torque Tbf, and the A-phase winding outputs a positive The electromagnetic torque Taf, the B-phase winding and the A-phase winding work together; when the electrical angle is between (240°, 360°), the C-phase inductance rises and the B-phase inductance decreases, at this time the control switch (Q3) is turned on Pass a positive current to the C-phase winding, pass a negative current to the B-phase winding, the reluctance torques of the C-phase winding and the B-phase winding cancel each other out, the C-phase winding outputs a positive electromagnetic torque Tcf, and the B-phase winding outputs a positive The electromagnetic torque Tbf, the C-phase winding and the B-phase winding work together.

Claims (1)

1. A low-cost three independent power supply electric vehicle drive system, comprising three independent power supplies, three switch tubes, three-phase double salient pole drive motors, position sensors, current sensors and control systems, is characterized in that: the three-phase The doubly salient drive motor is powered independently by the first independent power supply (U1), the second independent power supply (U2) and the third independent power supply (U3). The first independent power supply (U1) and the first switching tube (Q1) The first bridge arm is formed in series, the second independent power supply (U2) and the second switch tube (Q2) are connected in series to form the second bridge arm, and the third independent power supply (U3) and the third switch tube (Q3) are connected in series to form the third bridge arm , the three bridge arms are connected in series head-to-tail in sequence in a triangle connection, the first switch tube (Q1), the second switch tube (Q2) and the third switch tube (Q3) are respectively connected in parallel with the first body diode (D1), the second body diode Diode (D2) and third body diode (D3); the three-phase double salient pole drive motor is composed of three-phase windings, salient pole stator core, salient pole rotor core and shell, one end of the A-phase winding and the first The bridge arm is connected to the connection point of the second bridge arm, one end of the B-phase winding is connected to the connection point of the second bridge arm and the third bridge arm, and one end of the C-phase winding is connected to the connection point of the third bridge arm and the first bridge arm The other end of the three-phase winding is connected together to form a three-phase star winding. The pole arc coefficient of the stator core is 1/2, and the pole arc coefficient of the rotor core is 1/3. The three-phase double salient pole drive motor is both The field winding can be used for excitation, and the permanent magnet can also be used for excitation; the position sensor is used to detect the rotor position, and the control system controls the first switching tube (Q1), the second switching tube (Q2) and the third switching tube according to the detected position signal (Q3) is turned on or off; when the A-phase inductance rises and the C-phase inductance drops, the first switching tube (Q1) is controlled to conduct a positive current to the A-phase winding, and a negative current to the C-phase winding, and the A-phase winding Work together with the C-phase winding; when the B-phase inductance rises and the A-phase inductance drops, the second switching tube (Q2) is controlled to conduct a positive current to the B-phase winding and a negative current to the A-phase winding, and the B-phase winding and The A-phase windings work together; when the C-phase inductance rises and the B-phase inductance decreases, the third switching tube (Q3) is controlled to conduct a positive current to the C-phase winding, and a negative current to the B-phase winding, and the C-phase winding and the B-phase winding The phase windings work together; the current sensor is used to detect the current and send the signal to the control system to limit the current and protect the circuit; the control system receives the sensor, throttle and brake signals, and adjusts the sensor, throttle and brake signals. , throttle and brake signals are sent to the control unit, and the control unit outputs the driving signal of the switching tube after calculation, and the signal is sent to the first switching tube (Q1), the second switching tube (Q2) and the second switching tube (Q2) respectively after passing through the driving isolation circuit. Three switching tubes (Q3) realize the control of the system.