CN105634344B - A kind of three-phase position signal detection method of switched reluctance machines - Google Patents

Abstract

A three-phase position signal detection method of a switched reluctance motor. In the high-speed APC mode, the general-purpose timer TIM1 is used to input the capture channel to detect the A-phase Hall position signal HA to capture the time interval of one cycle of the position signal, and the captured The value is used as the reference time, and the switching time of the three-phase switching tube is calculated according to the three-phase switching angle value set in the APC mode. The timer TIM2 starts timing and interrupts according to the switching time of each phase, and combines the timer TIM3 to capture phase A. The falling edge calibration method is used to control and drive the turn-on and turn-off of the switch tubes of each phase of the power converter to realize the operation of the switched reluctance motor. The method can avoid the deviation of the Hall position signal caused by processing errors of the N and S poles of other magnetic rings, electromagnetic interference, etc., and achieve the effect of accurate detection of the three-phase Hall position signal of the reluctance motor.

Description

A three-phase position signal detection method of switched reluctance motor

technical field

The invention relates to a position signal detection method of a switched reluctance motor, in particular to a three-phase position signal detection method of a switched reluctance motor (SRM), belonging to the technical field of motor control.

Background technique

The switched reluctance motor drive system has outstanding features such as simple structure, low cost, flexible control, and good speed regulation performance. It is a new type of speed-adjustable drive system that has developed rapidly with the development of power electronic devices and modern control technology in the past 30 years. . It can maintain high efficiency in a wide range of speed and power, making it play an important role in high-performance applications such as aerospace, electric vehicle drives, household appliances, industry, etc.

In the application of driving systems such as electric vehicles, the driving system controls the running state of the motor according to the rotor position. Therefore, the position signal of the switched reluctance motor is the basis for the correct logic switching of the main switching devices of each phase and the determination of the winding commutation, and also provides the speed loop. the speed feedback signal. Therefore, accurate detection of position signals is particularly important. At present, the position signal detection of switched reluctance motors usually uses photoelectric encoders and Hall position sensors. , causing errors in the three-phase position signals, which ultimately affect the switching errors of the switching devices. This deviation has a particularly obvious impact on the switched reluctance motor when it is running at high speed, which will not only cause greater vibration of the motor, but also have a greater impact on the efficiency of the motor. Therefore, an accurate three-phase position signal detection method is needed to maintain the balance of the three-phase position signals and realize the reliable operation of the switched reluctance motor.

Contents of the invention

The present invention aims at the technical problem that the error in the three-phase position signal detection of the existing switched reluctance motor affects the performance of the driving system of the electric vehicle, etc., and proposes a three-phase position signal detection method of the switched reluctance motor (SRM). The relative position of the stator and rotor of the current motor can be obtained according to the Hall position signal fed back by the switched reluctance motor, so as to realize the opening of the corresponding phase limit of the SRM to drive the motor to run. It is especially suitable for high-speed control occasions. At this time, the motor is running in the angle position control (APC) mode, and accurate position detection is the key to realize the normal operation of the motor. This method can avoid the three-phase unbalance caused by the deviation of the position signal in the traditional position detection method, which will cause motor performance problems, and can realize the low error of the position signal detection of the switched reluctance motor, and maintain the balance of the three-phase position signal, so as to realize the correct commutation of the motor, The effect of reliable operation solves the application problem of switched reluctance motors in electric vehicle drive systems.

The technical scheme adopted by the present invention is as follows: a three-phase position signal detection method of a switched reluctance motor. The switched reluctance motor uses an asymmetrical half-bridge power converter as a power supply, and the Aup, Bup, and Cup signals are respectively used to control the three-phase bridge arm The signals of the upper and middle switching power tube grids, and And, Bdn, and Cdn are the driving signals of the middle and lower switching power tube grids of the three-phase bridge arm. The power converter turns on or off the motor winding to turn on the power to drive the motor. Complete the control process including excitation, freewheeling and return flow; in the high-speed angular position control APC mode, use the Hall position sensor to sample the three-phase position signal of the switched reluctance motor, and send the three-phase position signal to the microprocessor CPU;

It is characterized in that: according to the Hall position signal fed back by the switched reluctance motor, the relative position of the current motor stator and rotor is obtained, and the combination of the rising edge capture interrupt of the A phase position signal and the A phase falling edge trigger interrupt calibration realizes the reluctance motor. The accurate detection of the three-phase Hall position signal can achieve the opening of the corresponding phase limit of the switched reluctance motor; the specific method is: use the built-in general timer TIM1 input capture channel of the CPU to detect the rising edge of the A-phase Hall position signal, and capture The value is used as the reference time, and according to the three-phase switch angle value set in APC mode, the switching time of the three-phase upper and lower tubes is obtained through the calculation and interrupt program built in the microprocessor CPU, and then the general timer TIM2 built in the CPU is used according to The switching timing of each phase is interrupted, and the control signal of the switching power tube is obtained. At the same time, the built-in general timer TIM3 of the CPU is added to capture the falling edge of phase A to achieve calibration, so as to control and drive the switching tube of each phase of the power converter. And off, to achieve the operation of the switched reluctance motor.

The following steps can be used to achieve

1) Use the input capture channel of the built-in general-purpose timer TIM1 of the CPU to detect the two rising edges of the position signal of phase A, obtain the capture value In1, and use the capture value as the reference time for the motor to rotate one position signal period;

2) According to the capture value In1 of the timer TIM1, the motor rotor rotates through a 45° angle, that is, the time used for one position signal cycle, and calculates the time In2 used for each rotation of the motor rotor through 1°;

3) According to the opening and closing angle values θ _Aon and θ _Aoff of phase A set in APC mode and the time In2 used for each rotation of the rotor by 1°, calculate the opening and closing time In3 and In4 of the switching tube of phase A;

4) According to the turn-on and turn-off angle values of B and C phases set in APC mode θ _Bon , θ _Boff , θ _Con , θ _Coff , calculate the turn-on and turn-off times In5 and In6 of the switch tubes of B and C phases respectively , In7, In8;

5) The timer TIM2 sets the timing time according to the calculated turn-on and turn-off times of the switching tubes of each phase. It starts timing from the time point of the rising edge and enters the interruption. At this time, the position of the rotor is 0°. If each phase is turned on Or the turn-off angle is between 0 and 22.5°, and the corresponding switch tube is turned on or off;

6) Use the input capture channel of the timer TIM3 to detect the falling edge of the A-phase position signal, and use the captured value of the falling edge as the reference point for timing after the rotor position angle is 22.5 degrees;

7) The timer TIM2 sets the timing time according to the calculated turn-on and turn-off times of the switch tubes of each phase. It starts timing from the time point of the falling edge and enters the interruption. At this time, the rotor position is 22.5°. If each phase is turned on or When the turn-off angle is between 22.5° and 45°, the corresponding switch tube is turned on or off;

8) For other multi-phase switched reluctance motors, each phase adopts the same control method as above.

In the step 3), the turn-on time In3 and the turn-off time In4 of the A-phase switching tube are calculated according to the set A-phase turn-on and turn-off angle values θ _Aon , θ _Aoff and the time In2 used for each rotation of the rotor by 1° :

In3＝θ _Aon *In2

In4＝θ _Aoff *In2

Advantage of the present invention and beneficial effect:

1. The present invention can avoid the Hall position signal deviation caused by other magnetic ring N and S pole processing errors, electromagnetic interference, etc. The effect of accurate detection of three-phase Hall position signal of reluctance motor.

2. The present invention can realize low error in position signal detection of switched reluctance motors, maintain the balance of three-phase position signals, thereby realizing the effects of correct commutation and reliable operation of the motor, and is especially suitable for reluctance motors running at high speed in Hall position in APC mode The precise detection of signals avoids the problem of motor performance degradation caused by errors in traditional position signal detection due to factors such as ferrite ring processing, and solves the application problem of switched reluctance motors in electric vehicle drive systems.

3. The method of the present invention can avoid the three-phase unbalance caused by the deviation of the position signal in the traditional position detection method, causing motor performance problems, and can realize the low error of the position signal detection of the switched reluctance motor, and maintain the balance of the three-phase position signal, thereby realizing the correctness of the motor. The effects of commutation and reliable operation solve the application problem of the switched reluctance motor in the electric vehicle drive system.

4. Compared with the traditional direct position detection method using photoelectric encoder or Hall position sensor, the present invention has a position signal deviation. This detection method has better detection accuracy, and is also cheaper than methods such as signal correction after detection errors. , The advantages of fast speed.

Description of drawings

Fig. 1 is the operation flowchart of the position signal detection method of high-speed switched reluctance motor of the present invention;

Fig. 2 is a structural diagram of the entire switched reluctance motor control system after applying the present invention;

Fig. 3 is the structural diagram of the asymmetrical half-bridge circuit adopted by the power converter in the present invention;

Fig. 4 is a schematic diagram of waveforms of phase A Hall position signal and three-phase switch signal in the present invention.

Detailed ways

The specific method and operation process provided by the present invention will be described in detail below in conjunction with the accompanying drawings and examples (taking a three-phase 12/8-pole switched reluctance motor as an example).

The structural diagram of the entire switched reluctance motor control system after applying the present invention is shown in Figure 2, which provides power for the entire electric vehicle. Its working principle is that in the high-speed APC mode, the Hall position sensor is used to sample the three-phase position signal of the switched reluctance motor, and the three-phase position signal is sent to the microprocessor CPU, and the general-purpose timer TIM built in the CPU is used to input and capture The channel detects the rising edge of the A-phase Hall position signal, takes the captured value as the reference time, and according to the three-phase switch angle value set in the APC mode, obtains the three-phase up and down through the calculation and interrupt program built in the microprocessor CPU. The switching time of the tube, the timer TIM is used to enter the interrupt according to the switching time of each phase, and the control signal of the switching power tube is obtained, so as to control and drive the opening and closing of the switching tube of each phase of the power converter, combined with the speed control The AD sampling module is sent to the CPU through the external given signal to adjust the motor speed.

The power supply in Figure 2 is a half-bridge power converter, which usually provides current and a DC voltage of 48V-72V in electric vehicles. The Hall element US4881KUA is used as a position sensor to detect the rotor position of the reluctance motor.

The operation flowchart of the method of the present invention is as shown in Figure 1, at first adopts the input capturing channel of the built-in general timer TIM1 of processor CPU to detect two rising edges (i) of A phase position signal, obtains capturing value In1, as motor Rotate the reference time (ii) of one position signal cycle, according to the capture value In1 captured by the timer TIM1, the motor rotor rotates through an angle of 45°, and calculate the time In2(iii) for the rotor of the motor to rotate through 1°; according to In the APC mode, the values θ _Aon and θ _Aoff of the turn-on angle and turn-off angle of phase A and the time In2 used for each rotation of the rotor through 1° can be calculated to obtain the turn-on and turn-off time In3 and In4 of the phase A switch ( iv); Then, according to the turn-on and turn-off angle values θ _Bon , θ _Boff , θ _Con , θ _Coff of the B and C phases set in the APC mode, the turn-on and turn-off times In5 of the B and C phase switches are calculated respectively , In6, In7, In8(v); Use the input capture channel of the built-in timer TIM3 of the CPU to detect the falling edge of the position signal of phase A, and use the captured value of the falling edge as the reference point for timing after the rotor position angle is 22.5 degrees (vi); Timer TIM2 is set according to the calculated turn-on and turn-off time of each phase switch tube, starting from the rising edge (rotor position is 0°) and from the falling edge (rotor position is 22.5°) respectively. Start timing at two time points and enter the interruption (vii); according to whether the opening or closing angle in the phase is between 0 and 22.5° and between 22.5° and 45°, the corresponding switch tube (viii) is turned on or off;

For other multi-phase switched reluctance motors, each phase adopts the same control method as above.

The turn-on and turn-off angle values θ _Aon and θ _Aoff of phase A and the time In2 used for each rotation of the rotor by 1° can be calculated to obtain the turn-on and turn-off time In3 and In4 of the phase A switch. The formula is:

In3＝θ _Aon *In2

In4＝θ _Aoff *In2

FIG. 3 is a structural diagram of an asymmetrical half-bridge circuit used in the power converter of the present invention, which is a known circuit. The Aup, Bup, and Cup signals are signals for controlling the grid of the upper switching power transistor in the three-phase bridge arm, respectively, and Adn, Bdn, and Cdn are driving signals for the grid of the lower switching power transistor in the three-phase bridge arm. The power converter is connected to the power supply part by turning on or off the motor windings in turn, drives the motor to run, and completes the control processes such as excitation, freewheeling and backflow.

FIG. 4 is a schematic diagram of the waveforms of the A-phase Hall position signal HA and the three-phase switch signals in the present invention. The switched reluctance motor uses a switch-type Hall position sensor to detect the magnetic poles N and S of the magnetic ring, and outputs "0" and "1" respectively. The output waveform period is 45° and the duty cycle is 50%. The rising edge of phase A corresponds to the rotor position angle of 0°, that is, 45°, and the falling edge corresponds to the rotor position angle of 22.5°. The three-phase switch signal is active high, "1" means that the phase is on, and "0" means that the phase is off. When the motor is running forward, the three-phase commutation sequence is A->C->B->A, which corresponds to the turn-off angle θ _Aoff of phase A and the turn-on angle θ _Con of phase C between 0° and 22.5° , between 22.5° and 45° corresponds to the turn-on angle θ _Bon of phase B, the turn-off angle θ _Coff of phase C, the turn-on angle θ _Aon of phase A, and the turn-off angle θ _Boff of phase B. Turn on the excitation of the phase winding at the corner, turn off the phase winding at the relevant off angle, and switch to the next phase.

Compared with the traditional direct position detection method using a photoelectric encoder or a Hall position sensor, the position signal deviation occurs in the present invention. The detection method has higher detection accuracy, can avoid errors such as processing of N and S poles of other magnetic rings, and is also more accurate than the detection method. Methods such as signal correction after an error occurs have the advantages of low cost and high speed.

The specific implementation of the present invention has been described above with the help of examples, but it should be understood that the foregoing specific description should not be construed as limiting the spirit and scope of the present invention, and those of ordinary skill in the art will understand the above-mentioned examples after reading this description. Various modifications made belong to the protection scope of the present invention.

Claims (2)

1. a kind of three-phase position signal detection method of switched reluctance machines, switched reluctance machines are with asymmetrical half-bridge power conversion For device as power supply, Aup, Bup, Cup signal are respectively the signal for controlling upper switch power tube grid in three-phase bridge arm, Adn, Bdn, Cdn be three-phase bridge arm in lower switch power tube grid drive signal, power inverter by be switched on or off in turn motor around Group switches on power, and motor operation, completion includes excitation, afterflow and the control process of backflow；In high speed Angle-domain imaging Under APC patterns, sent using the three-phase position signal of hall position sensor sampling switch reluctance motor, and by three-phase position signal To microprocessor CPU；

It is characterized in that：The relative position of current motor rotor is obtained according to the hall sensor signal that switched reluctance machines feed back Put, interrupted by the rising edge capture of A phase position signals and A phases trailing edge triggers the combination for interrupting calibration, realize magnetic resistance The accurate detection of motor three-phase hall sensor signal, reach switched reluctance machines accordingly mutually limit it is open-minded；Specific method is：Utilize General purpose timer TIM1 input capture passages built in CPU go detect A phase hall sensor signals rising edge, using capture be worth as Fiducial time, and according to the threephase switch angle value set under APC patterns, by calculating built-in in microprocessor CPU, in Disconnected program obtains the switch time of down tube on three-phase, then during using the general purpose timer TIM2 built in CPU according to the switch of each phase Between timing enter interrupt, obtain switching power tube control signal, while add the general purpose timer TIM3 built in CPU to capture A The trailing edge of phase realizes calibration, is controlled and each phase switching tube of driving power converter being opened and turning off with this, realizes switch The operation of reluctance motor；

Comprise the following steps：

1) go to detect two rising edges of A phase position signals using the input capture passage of the general purpose timer TIM1 built in CPU, Capture value In1 is obtained, the fiducial time in a position signalling cycle is rotated using the capture value as motor；

2) it is that rotor turns over 45° angle degree according to timer TIM1 capture value In1, i.e. used in a position signalling cycle Time, the rotor that motor is calculated often turn over time In2 used in 1 °；

3) according to the opening of the A phases set under APC patterns, turn off angle value θ_Aon、θ_AoffTime is often turned over used in 1 ° with rotor In2, A phase switching tubes are calculated turns on and off time In3, In4；

4) according to the opening of B, C phase set under APC patterns, turn off angle value θ_Bon、θ_Boff、θ_Con、θ_Coff, it is calculated respectively B, C phases switching tube turns on and off time In5, In6, In7, In8；

5) timer TIM2 turns on and off the time the timing time that sets according to each phase switching tube being calculated, from upper Rise along this time point and start timing into interrupting, now the position of rotor is 0 °, is arrived if being switched on or off angle in each phase 0 Between 22.5 °, corresponding switching tube is switched on or off；

6) go to detect the trailing edge of A phase position signals, and catching the trailing edge using timer TIM3 input capture passage Obtain datum mark of the value as timing after 22.5 degree of rotor position angle；

7) timer TIM2 turns on and off the time the timing time that sets according to each phase switching tube being calculated, under Drop starts timing along this time point and enters interruption, and now rotor-position is 22.5 °, is existed if being switched on or off angle in each phase Between 22.5 ° to 45 °, corresponding switching tube is switched on or off；

8) if other multiphase switched reluctance machines, then each phase uses above-mentioned identical control method.

2. switched reluctance machines position signalling detection method according to claim 1, it is characterised in that：Basis in step 3) The A phases of setting are opened, turn off angle value θ_Aon、θ_AoffTime In2 used in 1 ° is often turned over rotor, A phase switching tubes are calculated Service time In3 and turn-off time In4：

In3=θ_Aon*In2

In4=θ_Aoff*In2。