CN108183636B - A dual-motor seven-switch inverter and its control method - Google Patents

Abstract

The invention discloses a dual three-phase motor seven-switch inverter and a control method. The seven-switch inverter is used to control the basic structure of a dual-motor system, and the actual rotational speeds of the two three-phase motors are obtained respectively, and the actual rotation speed of the two motors is calculated. After the speed and the given speed are adjusted, the speed error is obtained; then the speed error of the two three-phase motors is passed through the PI controller to obtain the given current of the two three-phase motors, and the obtained given current is obtained through the reference current generator. The reference current of the two three-phase motors, the current error is obtained by passing the reference current and the actual current through the current adjustment module, and the current error in the phase windings connected to each independent bridge arm is respectively sent to the hysteresis controller, and the hysteresis control The signal generated by the generator passes through the PWM generation unit, and the PWM generation unit is used to realize the control of the two three-phase motors. The invention is suitable for many different types of three-phase AC motors, and has the advantages of simple algorithm, fast response and high precision. , the implementation is simple, and the scope of application is wide.

Description

A dual-motor seven-switch inverter and its control method

technical field

The invention relates to the technical field of motor control, in particular to a dual-motor seven-switch inverter and a control method thereof.

Background technique

The dual-motor system can control the output torque of the two motors to eliminate the transmission gap and share the load. In recent years, with the higher demands of social life and industrial production, dual-motor control systems are widely used in papermaking, transportation, electric vehicles, washing machines, air conditioners and other home appliances. The multi-phase motor drive system has the characteristics of low voltage and high power output, high power density, small torque fluctuation, and is suitable for fault-tolerant operation, and has received extensive attention. In a dual-motor drive system, the need to control both motors at the same time presents a higher complexity for developers not only to deal with, but also to ensure safe operation in any situation, including safety in the event of equipment failure. In recent years, the five-leg inverter-driven dual-motor system has been widely studied, that is, the five-leg inverter containing ten power switches is used to control two independent three-phase motors, which is compared with the conventional six-legged motor. The 12-power switch inverter control scheme saves two power devices and reduces the system cost. However, using a five-arm inverter to drive a dual-motor system for dual-motor control is still complicated in structure, and the control method requires logic operation processing. Obtaining the actual switching states of the ten power switches of the inverter requires high operating hardware costs and complicated operation procedures.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a dual-motor seven-switch inverter and a control method thereof to overcome the deficiencies of the prior art.

To achieve the above object, the present invention adopts the following technical solutions:

A dual-motor seven-switch inverter, comprising a controller, a three-phase motor M1, a three-phase motor M2, and four inverter bridge arms L1, inverter bridge arms L2, and an inverter connected in parallel to the same DC power supply The bridge arm L3 and the inverter bridge arm L4; the inverter bridge arm L1 and the inverter bridge arm L2 include two series-connected power switch tubes, and the inverter bridge arm L3 includes three series-connected power switch tubes. The inverter bridge arm L4 is a capacitor inverter bridge arm;

The winding A of the three-phase motor M1 is connected to the midpoint a of the inverter bridge arm L1; the winding B of the three-phase motor M1 is connected to the midpoint b of the inverter bridge arm L2; the winding C of the three-phase motor M1 is connected to the capacitor variable bridge arm The midpoint c of L4 is connected;

The winding U of the three-phase motor M2 is connected to the midpoint x of the inverter bridge arm L2; the winding V of the three-phase motor M2 is connected to the midpoint y of the inverter bridge arm L3; the winding W of the three-phase motor M2 is connected to the fourth capacitor The midpoint c of the inverter bridge arm L4 is connected.

Further, the controller includes a current detection sensor, a Hall position sensor and a speed adjustment module, a PI controller, a reference current generator, a current adjustment module, a hysteresis controller and a PWM pulse generation unit connected in sequence; the PWM pulse generation unit The power switch tube connected to the bridge arm of the inverter; the current detection sensor is connected to the armature winding port of the three-phase motor to detect the three-phase current of the two three-phase motors, and send the detected three-phase current to the current regulator Module; Hall position sensor is used to detect the Hall signals of two three-phase motors and parse them into rotor position signals θ ₁ , θ ₂ and actual rotational speeds ω ₁ , ω ₂ of two three-phase motors through the central control unit, which will generate The rotor position signals θ ₁ and θ ₂ are sent to the reference current generator, and the generated actual rotational speeds ω ₁ and ω ₂ are sent to the speed adjustment module.

Further, the main control unit includes a position generating unit and a rotational speed generating unit, the position generating unit is used to parse the Hall signal detected by the Hall position sensor into rotor position signals θ ₁ , θ ₂ , and the rotational speed generating unit is used to The Hall position sensor analyzes the detected Hall signal into actual rotational speed ω ₁ , ω ₂ , transmits the generated rotor position signal θ ₁ , θ ₂ to the reference current generator, and transmits the generated actual rotational speed ω ₁ , ω ₂ to the speed regulation module.

Further, the power switch tubes all use IGBT or MOSFET.

Further, the two three-phase motors are three-phase motors, three-phase brushless DC motors, three-phase stepping motors or three-phase AC asynchronous motors.

A control method for a dual-motor seven-switch inverter, comprising the following steps: first, the actual rotational speed and rotor position signals of two three-phase motors are obtained respectively, and the actual rotational speed and the given rotational speed of the two motors are adjusted by speed to obtain the rotational speed Then, the speed error of the two three-phase motors is passed through the PI controller to obtain the given current of the two three-phase motors, and the obtained given current and rotor position signal are passed through the reference current generator to obtain the reference of the two three-phase motors. Current, the current error is obtained by passing the reference current and the actual current through the current adjustment module, and the current error in the phase windings connected to each independent bridge arm is sent to the hysteresis controller respectively, and the signal generated by the hysteresis controller is generated by PWM The unit uses the PWM generation unit to realize the control of the two three-phase motors.

Further, it specifically includes the following steps:

Step 1), the system is initialized, and the actual rotational speeds ω ₁ and ω ₂ of the two three-phase motors M ₁ and M ₂ are acquired and sent to the speed adjustment module, and the fixed reference rotational speeds ω ₁ ^* and ω ₂ ^* of the speed adjustment module are used. and the actual rotation speed ω ₁ , ω ₂ to obtain the rotation speed errors e _ω1 , e _ω2 , and send the obtained rotation speed errors e _ω1 , e _ω2 to the PI controller to obtain the given reference currents I ₁ ^* , I ₂ ^* and send them to the reference current generator , obtain the rotor Hall position signals θ ₁ and θ ₂ of the two three-phase motors M ₁ and M ₂ and transmit them to the reference current generator;

Step 2), utilize the current detection sensor to obtain the two-phase current signals _IA , _IB and _IU , _IV of the two three-phase motors and send them to the current adjustment module respectively;

The given currents I ₁ ^* and I ₂ ^* obtained in step 3) and step 1) and the rotor Hall position signals θ ₁ and θ ₂ of the two three-phase motors M ₁ and M ₂ are calculated by the reference current generator to obtain two Three-phase reference currents _IA ^* , _IB ^* and _IU ^* , _IV ^* of the three-phase motors M1, M2;

Step 4), the three-phase reference currents I _A ^* , I _B ^* and I _U ^* , I _V ^* of the two three-phase motors M1 and M2 and the actual detected currents I _A , I _B and I _U , I _V are in the current The corresponding current errors e ₁ , e ₂ and e ₄ , e ₅ of the two motors M1 and M2 are obtained after the current errors are respectively calculated in the adjustment module;

Step 5), using the four current errors e ₁ , e ₂ and e ₄ , e ₅ signals can be calculated to obtain six hysteresis controller input signals δ _k :

In the formula, k=1, 2, 3, 4, 5, 6;

After inputting the signal _δk to the six hysteresis controllers, the trigger signal S _m of the seven power switches T _m of the two-phase motor seven-switch three-phase inverter can be obtained, which can realize the control of the two motors M1 and M2. effective control.

Further, the actual rotational speed ω ₁ , ω ₂ of the two three-phase motors M1 and M2 obtained in step 1) and the given reference rotational speed ω ₁ ^* , ω ₂ ^* are passed through the speed adjustment module to obtain the rotational speed errors e _ω1 , e _ω2 :

The speed errors e _ω1 , e _ω2 obtain the given reference currents I ₁ ^* and I ₂ ^* through the PI controller:

In the formula, K _p is a positive proportional constant, and K _I is a positive integral constant.

Further, for a three-phase motor or a three-phase asynchronous motor, the three-phase reference currents of the two motors M1 and M2 are I _A ^* , I _B ^* and I _U ^* , I _V ^* respectively:

Further, the trigger signal S _m is calculated as follows:

In the formula, m=1, 2, 3, 4, 5, 6, 7, and ε is a small positive constant.

The present invention is a dual-phase motor seven-switch inverter. By using the seven-switch inverter to connect two three-phase motors at the same time, the time-sharing control of the two three-phase motors is realized, and the seven-switch inverter is used to control the dual-motor system. The basic structure of the inverter reduces the number of switching devices used, saves the coordinate transformation and calculation of the vector transformation method, and simplifies the mathematical model of the asynchronous motor for decoupling. There is no usual PWM pulse width modulation signal generator, the control structure is simple, and the control signal The physical concept of processing is clear, the torque response of the system is fast and there is no overshoot. It is an AC speed control method with high static and dynamic performance.

The invention provides a method for controlling a seven-switch inverter for a dual-phase motor. First, the actual rotational speeds of the two three-phase motors are obtained respectively, and the rotational speed error is obtained by adjusting the actual rotational speed and the given rotational speed of the two motors; The speed error of three three-phase motors is obtained through the PI controller to obtain the given currents of the two three-phase motors, and the obtained given currents are passed through the reference current generator to obtain the reference currents of the two three-phase motors. After the current adjustment module, the current error is obtained, and the current error in the phase windings connected to each independent bridge arm is sent to the hysteresis controller. For the control of two three-phase motors, the present invention is suitable for many different types of three-phase AC motors, and has the advantages of simple algorithm, fast response and high precision, simple implementation and wide application range.

Description of drawings

FIG. 1 is a schematic flowchart of a system control method of the present invention.

FIG. 2 is a schematic structural diagram of an inverter system of the present invention.

Fig. 3 is a system control circuit diagram of the present invention.

Detailed ways

Below in conjunction with accompanying drawing, the present invention is described in further detail:

As shown in Figures 2 and 3, a dual-motor seven-switch inverter includes a controller, a three-phase motor M1, a three-phase motor M2, and four inverter bridge arms L1, an inverter, and an inverter connected in parallel to the same DC power supply. The inverter bridge arm L2, the inverter bridge arm L3 and the inverter bridge arm L4; the inverter bridge arm L1 and the inverter bridge arm L2 include two power switch tubes connected in series, and the inverter bridge arm L3 includes three power switches. A power switch tube connected in series, the inverter bridge arm L4 is a capacitor inverter bridge arm;

The controller includes a current detection sensor, a Hall position sensor, a speed regulation module, a PI controller, a reference current generator, a current regulation module, a hysteresis controller and a PWM pulse generation unit connected in sequence; the PWM pulse generation unit is connected to the inverter The power switch tube of the bridge arm of the inverter; the current detection sensor is connected to the armature winding port of the three-phase motor to detect the three-phase current of the two three-phase motors, and sends the detected three-phase current to the current adjustment module; The Hall position sensor is used to detect the Hall signals of the two three-phase motors and parse them into the rotor position signals θ ₁ , θ ₂ and the actual rotational speeds ω ₁ , ω ₂ of the two three-phase motors through the central control unit, and the generated rotor position The signals θ ₁ and θ ₂ are sent to the reference current generator, and the generated actual rotational speeds ω ₁ and ω ₂ are sent to the speed adjustment module;

The main control unit includes a position generating unit and a rotational speed generating unit. The position generating unit is used to parse the Hall signal detected by the Hall position sensor into rotor position signals θ ₁ and θ ₂ , and the rotational speed generating unit is used to convert the Hall position The sensor analyzes the detected Hall signal into actual rotational speed ω ₁ , ω ₂ , transmits the generated rotor position signals θ ₁ , θ ₂ to the reference current generator, and transmits the generated actual rotational speed ω ₁ , ω ₂ to the speed adjustment module;

The winding A of the three-phase motor M1 is connected to the midpoint a of the inverter bridge arm L1; the winding B of the three-phase motor M1 is connected to the midpoint b of the inverter bridge arm L2; the winding C of the three-phase motor M1 is connected to the capacitor variable bridge arm The midpoint c of L4 is connected;

The winding U of the three-phase motor M2 is connected to the midpoint x of the inverter bridge arm L2; the winding V of the three-phase motor M2 is connected to the midpoint y of the inverter bridge arm L3; the winding W of the three-phase motor M2 is connected to the fourth capacitor The midpoint c of the inverter bridge arm L4 is connected;

The power switch tube adopts IGBT or MOSFET.

The two three-phase motors are three-phase motors, three-phase brushless DC motors, three-phase stepper motors or three-phase AC asynchronous motors.

As shown in Figure 1, a dual-motor seven-switch inverter control method includes the following steps. First, the actual speed and rotor position signals of the two three-phase motors are obtained respectively, and the actual speed and the given speed of the two motors are passed through After speed adjustment, the speed error is obtained; then the speed error of the two three-phase motors is passed through the PI controller to obtain the given current of the two three-phase motors, and the obtained given current and rotor position signal are passed through the reference current generator to obtain two The reference current of the three-phase motor, the current error is obtained by passing the reference current and the actual current through the current adjustment module, and the current error in the phase windings connected to each independent bridge arm is respectively sent to the hysteresis controller, and the hysteresis controller generates The signal passed through the PWM generation unit, and the PWM generation unit is used to realize the control of the two three-phase motors.

Specifically include the following steps:

Step 1), the system is initialized, and the Hall position sensor is used to collect the rotor Hall position signals of the two three-phase motors M ₁ and M ₂ into the main control unit, and the main control unit parses the Hall position signal into two The rotor position signals θ ₁ , θ ₂ and the actual rotational speeds ω ₁ , ω ₂ of the three-phase motor are sent into the speed adjustment module, and the obtained actual rotational speeds ω ₁ and ω ₂ of the two three-phase motors are sent to the speed adjustment module, and the obtained two The rotor position signals θ ₁ and θ ₂ of the three-phase motor are sent to the reference current generator, and the two-phase current signals I _A , I _B and I _U , _IV of the two three-phase motors are obtained by using the current detection sensor and sent to the into the current regulation module;

In step 2), the actual rotational speed ω ₁ , ω ₂ of the two three-phase motors M1 and M2 obtained in step 1) and the given reference rotational speed ω ₁ ^* , ω ₂ ^* are passed through the speed adjustment module to obtain the rotational speed error e _ω1 , e _ω2 :

The speed errors e _ω1 , e _ω2 obtain the given reference currents I ₁ ^* and I ₂ ^* through the PI controller:

In the formula, K _p is a positive proportional constant, and K _I is a positive integral constant;

In step 3), the given currents I ₁ ^* and I ₂ ^* obtained in step 2) and the rotor position signals θ ₁ and θ ₂ of the two three-phase motors obtained in step 1) are calculated through the reference current generator to obtain two Three-phase reference currents of three-phase motors M1 and M2; for three-phase motors or three-phase asynchronous motors, the three-phase reference currents of two motors M1 and M2 are I _A ^* , I _B ^* and I _U ^* , I _V ^* respectively :

Step 4), using the three-phase reference currents _IA ^* , _IB ^* , _IU ^* , _IV ^* of the two three-phase motors M1 and M2 obtained in step 3) and the actual detected current detected in step 1) After I _A , I _B , I _U , I _V respectively calculate the current error in the current adjustment module, the corresponding current errors e ₁ , e ₂ and e ₄ , e ₅ of the two motors M1 and M2 are obtained:

Step 5), using the four current errors e ₁ , e ₂ and e ₄ , e ₅ signals can be calculated to obtain six hysteresis controller input signals δ _k :

In the formula, k=1, 2, 3, 4, 5, 6;

After inputting the signal _δk to the six hysteresis controllers, the trigger signal S _m of the seven power switches T _m of the two-phase motor seven-switch three-phase inverter can be obtained, which can be realized by different switch states of the inverter. Effective control of two motors M1, M2.

In the formula, m=1, 2, 3, 4, 5, 6, 7, ⊙ represents logical and negation, and ε is a positive constant.

Claims (6)

1. The control method of the double-motor seven-switch inverter is characterized in that the double-motor seven-switch inverter comprises a controller, a three-phase motor M1, a three-phase motor M2, four inverter bridge arms L1, L2, L3 and L4, wherein the four inverter bridge arms are connected in parallel on the same direct-current power supply;

the inverter bridge arm L1 comprises two power switching tubes T1 and T2 which are connected in series, the connecting point of the T1 and the T2 is a midpoint a, the inverter bridge arm L2 comprises two power switching tubes T3 and T4 which are connected in series, the connecting point of the T3 and the T4 is a midpoint x, the inverter bridge arm L3 comprises three power switching tubes T5, T6 and T7 which are connected in series, the connecting point of the T5 and the T6 is a midpoint b, and the connecting point of the T6 and the T7 is a midpoint y; the inverter bridge arm L4 is a capacitor inverter bridge arm, the inverter bridge arm L4 comprises two capacitors C1 and C2 which are connected in series, and the connection point of the capacitors C1 and C2 is a midpoint C; a winding A of the three-phase motor M1 is connected with a midpoint a of an inverter bridge arm L1; a winding B of the three-phase motor M1 is connected with a midpoint B of an inverter bridge arm L3; a winding C of the three-phase motor M1 is connected with a midpoint C of the inverter bridge arm L4, and a winding U of the three-phase motor M2 is connected with a midpoint x of the inverter bridge arm L2; a winding V of the three-phase motor M2 is connected with a midpoint y of an inverter bridge arm L3; a winding W of the three-phase motor M2 is connected with a midpoint c of an inverter bridge arm L4;

wherein the controller comprises a position generating unit for analyzing Hall signal detected by the Hall position sensor into rotor position signal theta and a rotation speed generating unit₁、θ₂The rotating speed generating unit is used for analyzing the Hall signal detected by the Hall position sensor into an actual rotating speed omega₁、ω₂A rotor position signal θ to be generated₁、θ₂Transmitting to a reference current generator to generate an actual rotation speed omega₁、ω₂Transmitting to a speed adjusting module;

the method specifically comprises the following steps: step 1), initializing the system to obtain two three-phase motors M₁、M₂Actual rotational speed ω₁、ω₂And transmitted to a speed regulation module which regulates the speed according to a given reference speed omega₁ ^*、ω₂ ^*With the actual speed omega₁、ω₂Obtaining a rotational speed error e_ω1、e_ω2Will obtain the error e of the rotation speed_ω1、e_ω2Transmitting to PI controller to obtain given reference current I₁ ^*、I₂ ^*And transmitting to a reference current generator to obtain two three-phase motors M₁、M₂Rotor position signal theta₁、θ₂And transmitted to the reference current generator;

step 2), acquiring two-phase current signals I of two three-phase motors by using current detection sensors_A、I_BAnd I_U、I_VRespectively sending the signals into a current regulation module;

step 3), the given reference current I obtained in step 1)₁ ^*、I₂ ^*And two three-phase motors M₁、M₂Rotor position signal theta₁、θ₂Calculating two-phase reference current I of two three-phase motors M1 and M2 through a reference current generator_A ^*、I_B ^*And I_U ^*、I_V ^*；

Step 4), two-phase reference current I of two three-phase motors M1 and M2_A ^*、I_B ^*And I_U ^*、I_V ^*And the actually detected current I_A、I_BAnd I_U、I_VThe current error e corresponding to the two motors M1, M2 is obtained after the current error is respectively calculated in the current adjusting module₁、e₂And e₄、e₅；

Step 5) utilizing four current errors e₁、e₂And e₄、e₅The signals can be calculated to obtain six input signals of the hysteresis controller_k：

Wherein k is 1,2,3,4,5, 6;

then will the signal_kAfter being input into six hysteresis controllers, seven power switches T of the double three-phase motor seven-switch three-phase inverter can be obtained_mTrigger signal S_mEffective control of two motors M1 and M2 and trigger signal S_mThe calculation is as follows:

wherein m is 1,2,3,4,5,6,7, which is a positive constant.

2. The control method of the double-motor seven-switch inverter according to claim 1, wherein the controller comprises a current detection sensor, a Hall position sensor, a speed regulation module, a PI controller, a reference current generator, a current regulation module, a hysteresis controller and a PWM pulse generation unit which are connected in sequence; the PWM pulse generating unit is connected with a power switch tube of an inverter bridge arm; the current detection sensor is connected with the three-phase motorThe armature winding port is used for detecting the phase currents of the two three-phase motors and sending the detected phase currents to the current regulating module; the Hall position sensor is used for detecting Hall signals of the two three-phase motors and resolving the Hall signals into rotor position signals theta of the two three-phase motors through the controller₁、θ₂And the actual rotational speed omega₁、ω₂A rotor position signal θ to be generated₁、θ₂Transmitting to a reference current generator to generate an actual rotation speed omega₁、ω₂And transmitting to a speed adjusting module.

3. The method for controlling the two-motor seven-switch inverter as claimed in claim 1, wherein the power switch tubes are all IGBT or MOSFET.

4. The method of claim 1, wherein the three-phase motor is a three-phase brushless dc motor, a three-phase stepping motor or a three-phase ac asynchronous motor.

5. The method for controlling the two-motor seven-switch inverter as claimed in claim 1, wherein the speed adjusting module in step 1) is configured to adjust the speed according to a given reference rotation speed ω₁ ^*、ω₂ ^*With the actual speed omega₁、ω₂Obtaining a rotational speed error e_ω1、e_ω2The method specifically comprises the following steps:

error of rotation speed e_ω1、e_ω2Obtaining a given reference current I through a PI controller₁ ^*、I₂ ^*：

In the formula, K_pIs a positive proportionality constant, K_IA positive integration constant.

6. The method as claimed in claim 1, wherein the two-phase reference current I of two three-phase motors M1, M2_A ^*、I_B ^*And I_U ^*、I_V ^*Respectively as follows:

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