Hybrid level permanent magnet synchronous motor driving device and method

Abstract

The invention relates to the technical field of permanent magnet synchronous motors, in particular to a hybrid level permanent magnet synchronous motor driving device and method. The control device comprises a permanent magnet synchronous motor module, a vector control module, an extended Kalman filtering algorithm module, a zero sequence component module and a hybrid level inverter, the permanent magnet synchronous motor module is used for driving the mine tractor, and the vector control module achieves the purpose of controlling the permanent magnet synchronous motor by controlling the speed and current of the motor. The extended Kalman filtering algorithm module mainly replaces a traditional hardware type speed sensor, the zero-sequence component module controls voltage values of upper and lower capacitors on the direct current side of the hybrid level inverter, and the hybrid level inverter is connected with the permanent magnet synchronous motor and used for controlling normal operation of the permanent magnet synchronous motor. According to the invention, the manufacturing cost of the inverter is reduced, and the anti-interference capability of the control system is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of permanent magnet synchronous motors, and in particular to a hybrid level permanent magnet synchronous motor driving device and method. Background Art

[0002] In industrial and mining enterprises, mining traction electric locomotives are indispensable means of transportation. The performance of mining traction electric locomotives greatly affects the benefits of industrial and mining enterprises. Mining traction electric locomotives can be divided into two categories according to the different power supply methods, namely battery type and overhead wire type. In most enterprises, the working environment of mining traction electric locomotives is very bad. The main reasons are as follows:

[0003] First, the track conditions are poor. Usually, in order to save materials, industrial and mining enterprises lay narrow-gauge tracks for mine traction electric locomotives. On the one hand, most of these tracks are laid on the mountain or underground, which cannot ensure the flatness of the track, and the track turnouts and other related equipment are relatively simple; on the other hand, the maintenance of the track is relatively complicated and cumbersome, and the tracks in general enterprises are not well maintained, so mining electric locomotives are prone to slipping and derailment during operation.

[0004] Secondly, the power supply reliability of mining electric locomotives is low and the power quality is poor. For the more common overhead line electric locomotives, the pantograph of the electric locomotive and the overhead line frequently jump and have poor contact due to the simple overhead line equipment and uneven locomotive track laying. For battery electric locomotives, during operation, especially when the locomotive is heavily loaded, the voltage drop of the on-board power supply is more obvious, and it is impossible to stably provide high-quality power for the electric locomotive.

[0005] Finally, in order to save costs, the structure of mining electric locomotives is very simple. On the one hand, the tracks laid by industrial and mining enterprises for mining electric locomotives are mostly straight lines, which means that mining electric locomotives do not need to be equipped with bogies and other devices, and only need simple wheels, gear boxes and traction motors. In addition, the processing accuracy of wheels, gear boxes and other equipment is low, and the consistency between equipment is poor, resulting in the transmission performance of electric locomotives is not very ideal. On the other hand, the connection device between the locomotive and the bucket is simple, resulting in a large collision impact between the locomotive and the bucket.

[0006] Due to the above reasons, the operating environment of mine electric locomotives is harsh, so it is necessary to improve the control performance of mine electric locomotives by designing a suitable control system.

[0007] As a means of transport for transporting goods, the most important component of mining electric locomotives is the traction motor. At first, because DC traction motors have advantages such as good starting characteristics and strong overload capacity, the power of mining traction electric locomotives is mainly provided by DC traction motors. During this period, DC motors have an unshakable position in the field of electrical transmission. There are two main methods for DC motor speed regulation: series resistance speed regulation and DC chopper speed regulation. The series resistance speed regulation control strategy is to change the voltage across the DC motor armature by connecting the corresponding resistor in series with the motor armature, thereby adjusting the output speed of the DC motor. This method has a simple circuit and is easy to operate, but due to the increase in armature resistance, it will lead to increased energy loss, so the efficiency is significantly reduced. Although the DC speed regulation system has many advantages such as simple structure and easy operation, on the other hand, DC speed regulation has problems such as high cost of DC motors, complex maintenance, and easy sparks. With the rapid development of related disciplines such as power electronics technology, large-scale integrated circuits, and computer control technology, permanent magnet synchronous motors have gradually replaced the dominant position of DC motors in the field of electrical transmission with their advantages such as high efficiency and high power density. Permanent magnet synchronous traction locomotives have the advantages of high utilization rate and lower maintenance costs than DC locomotives. Therefore, permanent magnet synchronous motors are increasingly popular as mining traction locomotives.

[0008] With the continuous application of permanent magnet synchronous motors in mining traction locomotives, motor-related control systems are also developing and improving. The inverter equipment used in the control system of permanent magnet synchronous motors in the past was mainly two-level inverters, and the control technology was pulse width modulation technology, vector conversion control technology, and direct torque control. However, the working scene of mining traction vehicles is extremely complex, and it is necessary to develop high-power, high-voltage and strong anti-interference permanent magnet synchronous motor control devices. In recent years, permanent magnet synchronous motor control systems based on three-level inverters have been widely used in high-voltage and high-power scenarios. Compared with the two-level inverter, the power switch tube of each phase in the three-level inverter structure withstands a smaller voltage and lower switching loss. At the same time, the three-level inverter has a smaller voltage THD and dv / dt, and the output voltage waveform is closer to a sine wave. At present, typical three-level inverter topologies include NPC inverters, flying capacitor (FC) inverters, and cascaded H-bridge (CHB) inverters with independent DC power supplies. The T-type three-level inverter is an improved topology of the NPC inverter. Compared with the NPC inverter, the T-type three-level inverter uses two fewer clamping diodes in each phase bridge arm, which reduces losses, improves inverter efficiency, and improves the uneven distribution of switching losses of the switch tube in the NPC topology.

[0009] At present, there have been many in-depth studies on the control of permanent magnet synchronous motors based on T-type three-level inverters. In the face of the midpoint voltage fluctuation and common-mode voltage problems of T-type three-level inverters, some researchers use model predictive control to suppress the common-mode voltage of permanent magnet synchronous motor control systems and balance the midpoint voltage. Some researchers have also proposed a modulation method that can achieve common-mode voltage suppression and midpoint potential balance within the full modulation ratio and full power factor range. In the control system of permanent magnet synchronous motors with T-type three-level inverters, some researchers have proposed a two-step prediction MPTC improvement strategy. The improvement strategy can well realize the control of flux linkage, electromagnetic torque and midpoint potential, while solving the problem of large calculation amount of traditional two-step prediction MPTC.

[0010] Although there are many in-depth studies on the three-level inverter permanent magnet synchronous motor control system, there are still some problems. First, the T-type three-level inverter has a complex structure. A complete T-type three-level inverter requires 12 IGBT power switch tubes, and each bridge arm is connected in a "T" shape. The circuit structure is complex, the manufacturing cost is high, and the fault tolerance rate is low; second, the three-level inverter permanent magnet synchronous motor control algorithm is complex. The three-level control system needs to control the switching of 12 IGBT power switch tubes, and the algorithm is extremely complex; third, the three-level inverter permanent magnet synchronous motor control system has weak anti-interference ability. Mining tractors work in mines and are easily subject to strong interference. Traditional photoelectric encoder speed sensors are easily interfered, resulting in inaccurate motor speed measurement. Summary of the invention

[0011] The technical problem to be solved by the embodiments of the present invention is to provide a hybrid level permanent magnet synchronous motor drive device and method to solve the problems of complex structure, high algorithm difficulty and weak anti-interference ability in the prior art for the three-level inverter permanent magnet synchronous motor control system.

[0012] The present invention discloses a hybrid level permanent magnet synchronous motor drive device, comprising a permanent magnet synchronous motor module, a vector control module, an extended Kalman filter algorithm module, a zero sequence component module and a hybrid level inverter;

[0013] The permanent magnet synchronous motor module includes a permanent magnet motor for driving a mining traction locomotive;

[0014] The vector control module includes a speed control submodule, a current control submodule, a coordinate transformation submodule and a sinusoidal pulse width modulation submodule. The speed control submodule is electrically connected to the extended Kalman filter algorithm module, and is used to compare the predicted value and the reference value of the extended Kalman filter algorithm module and output a control signal. The current control submodule is connected to the permanent magnet synchronous motor module, and is used to compare the measured value and the reference value of the permanent magnet synchronous motor and output a control signal. The coordinate transformation submodule is respectively connected to the current control submodule, the extended Kalman filter algorithm module and the sinusoidal pulse width modulation submodule, and is used to perform data transformation between a natural coordinate system, a stationary coordinate system and a synchronous rotating coordinate system. The sinusoidal pulse width modulation submodule is connected to the mixed level inverter, and is used to control the switching state of the mixed level inverter.

[0015] The extended Kalman filter algorithm module is connected to the speed control submodule and the coordinate transformation submodule, and is used to accurately and real-time estimate the speed of the permanent magnet synchronous motor rotor and the position of the magnetic pole, so as to realize the sensorless control of the permanent magnet synchronous motor;

[0016] The zero-sequence component module is connected to the sinusoidal pulse width modulation submodule and is used to balance the midpoint voltage of the hybrid level inverter;

[0017] The hybrid level inverter is connected to the permanent magnet synchronous motor and is used to control the normal operation of the permanent magnet synchronous motor.

[0018] Preferably, the speed control submodule includes a speed comparison subunit and a speed PI regulator.

[0019] The speed comparison subunit is connected to the extended Kalman filter algorithm module and is used to compare the actual speed estimated by the permanent magnet synchronous motor with a reference speed;

[0020] The speed PI regulator is electrically connected to the speed comparison subunit, and is used to output a reference current of the permanent magnet synchronous motor according to an error between the estimated speed and the reference speed. Optionally, the parameter acquisition unit includes a speed comparison subunit, a PI regulator, a torque calculation subunit, a measurement calculation subunit, and a torque comparison unit;

[0021] Preferably, the current control submodule includes a current comparison subunit and a current PI regulator.

[0022] The current comparison subunit is connected to the permanent magnet synchronous motor and is used to compare the actual current of the permanent magnet synchronous motor with a reference current;

[0023] The current PI regulator is connected to the current comparison subunit and is used to output a current control signal according to an error between an actual current and a reference current.

[0024] Preferably, the coordinate transformation submodule is divided into three different forms of coordinate transformation. Form one transforms the three-phase current and three-phase voltage signals of the motor from a natural coordinate system to a stationary coordinate system for the calculation of the extended Kalman filter algorithm module. Form two transforms the current value of the stationary coordinate system to a synchronous rotating coordinate system for the input of the current comparison subunit. Form three transforms the voltage value of the synchronous rotating coordinate system to a stationary coordinate system for the input of the sinusoidal pulse width modulation submodule.

[0025] Preferably, the hybrid level inverter is connected to the permanent magnet synchronous motor to control the normal operation of the permanent magnet synchronous motor. The right side of the hybrid level inverter is composed of 10 IGBT power elements. The first two bridge arms are composed of 4 IGBT power elements each, showing a "T" type connection. The third bridge arm is composed of 2 IGBT power elements, showing a "1" type connection. The left side is connected to the right side by a DC power supply and two electrolytic capacitors with completely equal capacitance values.

[0026] Preferably, the sinusoidal pulse width modulation submodule includes a coordinate transformation submodule and a pulse width modulation algorithm for the mixed-level inverter. The coordinate transformation submodule is in the form of converting the voltage value of the stationary coordinate system into the natural coordinate system, injecting the zero-sequence component to obtain a three-phase modulation signal. The pulse width modulation algorithm for the mixed-level inverter requires that the first two phases of the modulation signal remain unchanged and the third phase modulation signal is shifted.

[0027] Preferably, the zero-sequence component module is connected to the sinusoidal pulse width modulation sub-module. Due to the particularity of the mixed-level inverter structure, the output of the zero-sequence component module is affected by the current of the first two bridge arms and the modulation voltage. The zero-sequence component module is used to balance the midpoint voltage of the mixed-level inverter.

[0028] Preferably, the hybrid level inverter comprises a first bridge arm, a second bridge arm, and a third bridge arm, and the three-phase winding of the permanent magnet synchronous motor comprises a first terminal, a second terminal, and a third terminal.

[0029] The first terminal of the permanent magnet synchronous motor is electrically connected to the first bridge arm, the second terminal is electrically connected to the second bridge arm, and the third terminal is electrically connected to the third bridge arm.

[0030] The present invention also provides a control method, characterized in that the control method comprises:

[0031] S1. Obtaining the actual speed, magnetic pole position, three-phase current value and three-phase voltage value of the permanent magnet synchronous motor;

[0032] S2. Obtaining voltage values ​​of two electrolytic capacitors of the hybrid level inverter;

[0033] S3, comparing the actual speed obtained in step S1 with the reference speed, inputting the error value between the two into the speed PI controller, thereby outputting a q-axis current control reference signal, and setting the d-axis current reference signal to 0;

[0034] S4, according to the magnetic pole position and three-phase current value obtained in step S1, the actual value of the d-axis current and the actual value of the q-axis current are obtained through coordinate transformation, the actual value of the d-axis current is compared with the d-axis current reference signal, and the error value between the two is input into the d-axis current PI controller, thereby outputting a d-axis voltage signal, the actual value of the q-axis current is compared with the q-axis current reference signal, and the error value between the two is input into the q-axis current PI controller, thereby outputting a q-axis voltage signal;

[0035] S5, obtaining an α-axis voltage signal and a β-axis voltage signal through coordinate transformation according to the d-axis voltage signal and the q-axis voltage signal obtained in step S4 and the magnetic pole position obtained in step S1;

[0036] S6, according to the α-axis voltage signal and the β-axis voltage signal obtained in step S5, the two are first transformed into a natural coordinate system in the sinusoidal pulse width modulation submodule to obtain voltage values ​​on the A-axis, the B-axis and the C-axis, and the voltage value of the natural coordinate system is added to the output of the zero-sequence component module as the motor modulation signal, the voltage values ​​of the A-axis and the B-axis are the modulation signals of the first bridge arm and the second bridge arm of the hybrid level inverter, and the voltage value of the C-axis is first translated and then used as the modulation signal of the third bridge arm of the hybrid level inverter;

[0037] S7, according to the modulation signals of the first bridge arm and the second bridge arm obtained in step S6, the first phase and the second phase current values ​​of step S1, and the voltage values ​​of the two electrolytic capacitors obtained in step S2, these data are substituted into the zero-sequence component calculation formula to obtain the zero-sequence component injection value, and the zero-sequence component injection value will be injected into the modulation signals of the first bridge arm, the second bridge arm and the third bridge arm of the hybrid level inverter to balance the midpoint voltage of the hybrid level inverter;

[0038] S8. According to the modulation signals obtained in steps S6 and S7, the switching states of the power devices in the hybrid level inverter are controlled by hardware implementation of carrier stacking PWM and two-level SPWM, so as to achieve the purpose of controlling the operation of the motor.

[0039] Preferably, the method for obtaining the actual speed and magnetic pole position of the permanent magnet synchronous motor includes:

[0040] S1. According to the obtained three-phase current values ​​and three-phase voltage values, coordinates are transformed into a stationary coordinate system to obtain an α-axis current, a β-axis current, an α-axis voltage, and a β-axis voltage;

[0041] S2. Using the obtained α-axis current, β-axis current, α-axis voltage, and β-axis voltage as inputs of an extended Kalman filter algorithm, the extended Kalman filter algorithm estimates the actual speed and magnetic pole position of the permanent magnet synchronous motor based on a mathematical model of the permanent magnet synchronous motor and input conditions;

[0042] S3. According to the extended Kalman filter algorithm, speed estimation based on the extended Kalman filter algorithm can be applied in complex working environments, and has strong anti-noise and anti-interference capabilities.

[0043] Preferably, the main circuit of the three-phase T-type inverter with the topological structure of the mixed level inverter is composed of 10 IGBT power elements, the first bridge arm and the second bridge arm each have 4 power switch tubes, the 4 power switch tubes of each bridge arm are connected in a "T" shape, the third bridge arm has 2 power switch tubes, the first bridge arm, the second bridge arm and the third bridge arm are respectively connected to the U phase, V phase and W phase of the motor, and the three bridge arms are connected to two electrolytic capacitors with completely equal capacitance values.

[0044] Preferably, the hybrid level inverter uses a zero-sequence component injection method to balance the midpoint voltage of the inverter, and the midpoint voltage balance problem refers to the fluctuation of the potential at the midpoint connected to the two capacitors at the DC end of the three-level inverter due to charging and discharging. For the hybrid level inverter, the midpoint voltage fluctuation will be affected when the power switches of the first bridge arm and the second bridge arm are turned on.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] Compared with the conventional T-type three-level inverter permanent magnet synchronous motor control system, the present invention, on the one hand, changes the T-type three-level inverter into a hybrid level inverter, reduces the number of two power switch tubes, and reduces the manufacturing cost of the inverter; on the other hand, a new midpoint zero-sequence component injection algorithm and a new pulse width modulation algorithm are used for the hybrid level inverter to control the midpoint voltage and the hybrid level inverter; finally, an extended Kalman filter algorithm is used to estimate the speed and magnetic pole position of the motor, thereby improving the anti-interference ability of the control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A schematic diagram of the overall structure of a hybrid level permanent magnet synchronous motor drive device provided by an embodiment of the present invention;

[0048] Figure 2 A topological structure diagram of a hybrid level inverter provided in an embodiment of the present invention;

[0049] Figure 3 Modulation principle diagram of the carrier stacking PWM method and the two-level SPWM method provided in the embodiments of the present invention;

[0050] Figure 4 The figure shows a voltage value variation diagram of the upper and lower capacitors on the DC side of the hybrid level inverter provided by an embodiment of the present invention;

[0051] Figure 5 A schematic diagram of simulation of the change of current of a permanent magnet synchronous motor with speed provided by an embodiment of the present invention;

[0052] Figure 6 A schematic diagram of a simulation of a permanent magnet synchronous motor current changing with load torque provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0053] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. Now, in conjunction with the accompanying drawings, the preferred embodiments of the present invention are described in detail.

[0054] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments:

[0055] The present invention discloses a hybrid level permanent magnet synchronous motor drive device, such as Figure 1 As shown, it includes a permanent magnet synchronous motor module, a vector control module, an extended Kalman filter algorithm module, a zero-sequence component module and a hybrid level inverter;

[0056] The permanent magnet synchronous motor module includes a permanent magnet motor for driving a mining traction locomotive;

[0057] The vector control module includes a speed control submodule, a current control submodule, a coordinate transformation submodule and a sinusoidal pulse width modulation submodule. The speed control submodule is electrically connected to the extended Kalman filter algorithm module, and is used to compare the predicted value and the reference value of the extended Kalman filter algorithm module and output a control signal. The current control submodule is connected to the permanent magnet synchronous motor module, and is used to compare the measured value and the reference value of the permanent magnet synchronous motor and output a control signal. The coordinate transformation submodule is respectively connected to the current control submodule, the extended Kalman filter algorithm module and the sinusoidal pulse width modulation submodule, and is used to perform data transformation between a natural coordinate system, a stationary coordinate system and a synchronous rotating coordinate system. The sinusoidal pulse width modulation submodule is connected to the mixed level inverter, and is used to control the switching state of the mixed level inverter.

[0058] The extended Kalman filter algorithm module is connected to the speed control submodule and the coordinate transformation submodule, and is used to accurately and real-time estimate the speed of the permanent magnet synchronous motor rotor and the position of the magnetic pole, so as to realize the sensorless control of the permanent magnet synchronous motor;

[0059] The zero-sequence component module is connected to the sinusoidal pulse width modulation submodule and is used to balance the midpoint voltage of the hybrid level inverter;

[0060] The hybrid level inverter is connected to the permanent magnet synchronous motor and is used to control the normal operation of the permanent magnet synchronous motor.

[0061] Preferably, the speed control submodule includes a speed comparison subunit and a speed PI regulator;

[0062] The speed comparison subunit is connected to the extended Kalman filter algorithm module and is used to compare the actual speed estimated by the permanent magnet synchronous motor with a reference speed;

[0063] The speed PI regulator is electrically connected to the speed comparison subunit, and is used to output a reference current of the permanent magnet synchronous motor according to an error between the estimated speed and the reference speed. Optionally, the parameter acquisition unit includes a speed comparison subunit, a PI regulator, a torque calculation subunit, a measurement calculation subunit, and a torque comparison unit;

[0064] Preferably, the current control submodule includes a current comparison subunit and a current PI regulator;

[0065] The current comparison subunit is connected to the permanent magnet synchronous motor and is used to compare the actual current of the permanent magnet synchronous motor with a reference current;

[0066] The current PI regulator is connected to the current comparison subunit and is used to output a current control signal according to an error between an actual current and a reference current.

[0067] Preferably, the coordinate transformation submodule is divided into three different forms of coordinate transformation. Form one transforms the three-phase current and three-phase voltage signals of the motor from a natural coordinate system to a stationary coordinate system for the calculation of the extended Kalman filter algorithm module. Form two transforms the current value of the stationary coordinate system to a synchronous rotating coordinate system for the input of the current comparison subunit. Form three transforms the voltage value of the synchronous rotating coordinate system to a stationary coordinate system for the input of the sinusoidal pulse width modulation submodule.

[0068] Preferably, the hybrid level inverter is connected to the permanent magnet synchronous motor to control the normal operation of the permanent magnet synchronous motor. The right side of the hybrid level inverter is composed of 10 IGBT power elements. The first two bridge arms are composed of 4 IGBT power elements each, showing a "T" type connection. The third bridge arm is composed of 2 IGBT power elements, showing a "1" type connection. The left side is connected to the right side by a DC power supply and two electrolytic capacitors with completely equal capacitance values.

[0069] Preferably, the sinusoidal pulse width modulation submodule includes a coordinate transformation submodule and a pulse width modulation algorithm for the mixed-level inverter. The coordinate transformation submodule is in the form of converting the voltage value of the stationary coordinate system into the natural coordinate system, injecting the zero-sequence component to obtain a three-phase modulation signal. The pulse width modulation algorithm for the mixed-level inverter requires that the first two phases of the modulation signal remain unchanged and the third phase modulation signal is shifted.

[0070] Preferably, the zero-sequence component module is connected to the sinusoidal pulse width modulation sub-module. Due to the particularity of the mixed-level inverter structure, the output of the zero-sequence component module is affected by the current of the first two bridge arms and the modulation voltage. The zero-sequence component module is used to balance the midpoint voltage of the mixed-level inverter.

[0071] Preferably, the hybrid level inverter comprises a first bridge arm, a second bridge arm, and a third bridge arm, and the three-phase winding of the permanent magnet synchronous motor comprises a first terminal, a second terminal, and a third terminal;

[0072] The first terminal of the permanent magnet synchronous motor is electrically connected to the first bridge arm, the second terminal is electrically connected to the second bridge arm, and the third terminal is electrically connected to the third bridge arm;

[0073] Figure 2 The topological structure diagram of the hybrid level inverter is shown in Figure 1. The main circuit of the three-phase T-type inverter consists of 10 IGBT power components, of which S xi (x=a,b,c,i=1,2,3,4). Both L1 and L2 bridge arms have 4 power switch tubes, S a2 and S a3 , S b2 and S b3 The four power switches in each bridge arm are connected in a "T" shape. The L3 bridge arm has two power switches. The L1, L2 and L3 bridge arms are connected to the U phase, V phase and W phase of the motor respectively. C1 and C2 are two electrolytic capacitors with exactly the same capacitance value. The midpoint O of C1 and C2 is selected as the reference point, then the voltage at point P is V dc / 2, the voltage at point O is 0, and the voltage at point N is -V dc / 2, the switching state and output voltage of the mixed-level inverter are shown in Table 1.

[0074] Table 1 Switching states and output voltages of mixed-level inverters

[0075]

[0076]

[0077] In the table, "1" represents the on-state of the switch tube, and "0" represents the off-state of the switch tube.

[0078] The present invention also provides a control method, characterized in that the control method comprises:

[0079] S1. Obtaining the actual speed, magnetic pole position, three-phase current value and three-phase voltage value of the permanent magnet synchronous motor;

[0080] S2. Obtaining voltage values ​​of two electrolytic capacitors of the hybrid level inverter;

[0081] S3: Compare the actual speed obtained in step S1 with the reference speed, and input the error value between the two into the speed PI controller to output the q-axis current control reference signal. D-axis current reference signal Set to 0;

[0082] Q-axis current control reference signal The calculation formula is:

[0083]

[0084] in:

[0085] is the q-axis reference current of the permanent magnet synchronous motor,

[0086] K pω is the proportional coefficient obtained through calculation or debugging,

[0087] K iω is the integral coefficient obtained through calculation or debugging,

[0088] w is the actual mechanical angular velocity of the permanent magnet synchronous motor,

[0089] w * is the reference angular velocity of the permanent magnet synchronous motor;

[0090] S4, according to the magnetic pole position and three-phase current value i obtained in step S1 abc After Clark transformation and Park transformation, the actual value of the d-axis current i is obtained. d and the actual value of the q-axis current i q , the actual value of the d-axis current is compared with the d-axis current reference signal, and the error value between the two is input into the d-axis current PI controller, thereby outputting the d-axis voltage signal u d , the actual value of the q-axis current is compared with the q-axis current reference signal, and the error value between the two is input into the q-axis current PI controller, thereby outputting the q-axis voltage signal u q ;

[0091] The Clark transformation formula for three-phase current and three-phase voltage is:

[0092]

[0093] The Park transformation formula is:

[0094]

[0095] d-axis voltage signal u d , q-axis voltage signal u q The calculation formula is:

[0096]

[0097] in:

[0098] i α 、i β 、u α 、u β are the α-axis and β-axis current and voltage values ​​obtained by Clark transformation,

[0099] i a 、i b 、i c is the three-phase current value in the natural coordinate system,

[0100] θ is the magnetic pole position of the permanent magnet synchronous motor,

[0101] K pd is the proportional coefficient of the d-axis current PI controller obtained through calculation or debugging,

[0102] K id is the integral coefficient of the d-axis current PI controller obtained through calculation or debugging,

[0103] K pq is the proportional coefficient of the q-axis current PI controller obtained through calculation or debugging,

[0104] K iq It is the integral coefficient of the q-axis current PI controller obtained through calculation or debugging;

[0105] S5, according to the d-axis voltage signal and the q-axis voltage signal obtained in step S4 and the magnetic pole position obtained in step S1, the α-axis voltage signal is obtained by inverse park transformation and β-axis voltage signal

[0106] The inverse park transformation formula is:

[0107]

[0108] S6, according to the α-axis voltage signal and the β-axis voltage signal obtained in step S5, both are first transformed into a modulation signal V by inverse Clark transformation in the sine pulse width modulation submodule.ra1 ,

[0109] V rb1 、V rc1 , V ra1 、V rb1 、V rc1 It will be added to the output value V0 of the zero-sequence component module to obtain the new modulation signal V ra 、V rb 、V rc , V ra 、V rb The modulation signals of the first bridge arm and the second bridge arm of the hybrid level inverter, V rc After being translated to the positive half axis, it is used as a modulation signal of the third bridge arm of the hybrid level inverter;

[0110] The inverse Clark transform formula is:

[0111]

[0112] New modulation signal V ra 、V rb 、V rc The calculation formula is:

[0113]

[0114] S7, obtaining the first bridge arm modulation signal V according to step S6 ra1 and the second bridge arm modulation signal V rb1 , the first-phase and second-phase current values ​​of step S1, the voltage values ​​of the two electrolytic capacitors obtained in step S2, substituting these data into the zero-sequence component calculation formula can obtain the zero-sequence component injection value V0, and the zero-sequence component injection value will be injected into the modulation signals of the first bridge arm, the second bridge arm and the third bridge arm of the hybrid level inverter to balance the midpoint voltage of the hybrid level inverter.

[0115] The calculation formula of zero-sequence component injection value V0 is:

[0116]

[0117] Define the symbolic function sgn(V rx ) is:

[0118]

[0119] Where i npcon The calculation formula is:

[0120]

[0121] ΔV dc =ΔV dc1-ΔV dc2

[0122]

[0123] Where C is the capacitance of the upper and lower capacitors of the hybrid level inverter, T s is the PWM carrier period;

[0124] S8. According to the modulation signals obtained in steps S6 and S7, the switching states of the power devices in the hybrid level inverter are controlled by hardware implementation of carrier stacking PWM and two-level SPWM, so as to achieve the purpose of controlling the operation of the motor.

[0125] Preferably, the method for obtaining the actual speed and magnetic pole position of the permanent magnet synchronous motor includes:

[0126] S1. According to the obtained three-phase current value and three-phase voltage value, the coordinates are transformed into the stationary coordinate system to obtain the α-axis current i α , β-axis current i β 、α-axis voltage u α , β-axis voltage u β ;

[0127] S2. Using the obtained α-axis current, β-axis current, α-axis voltage, and β-axis voltage as inputs of an extended Kalman filter algorithm, the extended Kalman filter algorithm estimates the actual speed and magnetic pole position of the permanent magnet synchronous motor based on a mathematical model of the permanent magnet synchronous motor and input conditions;

[0128] S3. According to the extended Kalman filter algorithm, speed estimation based on the extended Kalman filter algorithm can be applied in complex working environments, and has strong anti-noise and anti-interference capabilities.

[0129] Preferably, the main circuit of the three-phase T-type inverter topology of the mixed level inverter is composed of 10 IGBT power elements, the L1 bridge arm and the L2 bridge arm each have 4 power switch tubes, the 4 power switch tubes of each bridge arm are connected in a "T" shape, the third bridge arm has 2 power switch tubes, the L1, L2 bridge arms and L3 are respectively connected to the U phase, V phase and W phase of the motor, and the three bridge arms are connected to two electrolytic capacitors with completely equal capacitance values.

[0130] Preferably, the hybrid level inverter uses a zero-sequence component injection method to balance the midpoint voltage of the inverter. The midpoint voltage balance problem refers to the fluctuation of the potential at the midpoint connected to the two capacitors at the DC end of the three-level inverter due to charging and discharging. For the hybrid level inverter, the midpoint voltage fluctuation will be affected when the power switches of the L1 and L2 bridge arms are turned on.

[0131] Figure 3The modulation principle diagram of the carrier stacking PWM method and the two-level SPWM method. The modulation wave range of L1 and L2 phases is [-1, 1]. The modulation wave is divided into positive half-cycle and negative half-cycle. The positive half-cycle modulation wave is compared with carrier 1 to control the switch of the power switch tube, so that the output level is P. The negative half-cycle modulation wave is compared with carrier 2 to control the switch of the power switch tube, so that the output level is N. The output level is O in other states; the modulation wave range of L3 phase is [0, 2], all are positive cycles, and the modulation wave is compared with carrier 3 to control the switch of the power switch tube, so as to output high and low complementary levels.

[0132] In order to verify the feasibility of the dual induction motor control device for the highway traffic tunnel fan of the embodiment of the present invention, the present invention also conducts Matlab / Simulink experimental verification on the system. The basic parameters of the permanent magnet synchronous motor used in the simulation are the number of magnetic poles P = 2, the fixed flux linkage Ψ

[0133] =0.024148Wb.

[0134] like Figure 4 The figure shows the voltage change of the upper and lower capacitors on the DC side, which is used to reflect the control of the midpoint balance. When the midpoint balance control algorithm is not added, the voltage values ​​of the upper and lower capacitors of the hybrid level inverter will fluctuate greatly. When the midpoint voltage balance algorithm is added at a certain moment, the voltage values ​​of the upper and lower capacitors on the DC side quickly converge to 24V and remain stable, verifying the effectiveness of the proposed algorithm.

[0135] like Figure 5 The figure shows the speed and current changes during acceleration. Set the reference speed n ref The reference speed is 1300r / min, and at a certain moment the reference speed is increased to 1500r / min. At this time, the actual speed of the motor increases to the reference speed and remains stable. The actual speed of the motor is estimated by the extended Kalman filter algorithm. During the acceleration of the motor, the amplitude of the three-phase current will increase. After the motor speed stabilizes, the amplitude of the three-phase current will fall back until it stabilizes.

[0136] like Figure 6 The figure shows the change of torque and current during loading. The initial load of the motor is 0.1N·m. At a certain moment, the load is increased to 0.25N·m. At this time, the torque T of the motor is measured. e And the three-phase current I abc like Figure 6 As shown in the figure, when the load increases, the amplitude of the three-phase current of the motor will increase.

[0137] pass Figure 4 , Figure 5 , Figure 6 The simulation results show that the control system and method of the embodiment of the present invention are effective and meet expectations.

Claims

1. A hybrid level permanent magnet synchronous motor drive device, characterized in that: The control device includes a permanent magnet synchronous motor module, a vector control module, an extended Kalman filter algorithm module, a zero-sequence component module and a hybrid level inverter; The permanent magnet synchronous motor module includes a permanent magnet motor for driving a mining traction locomotive; The vector control module includes a speed control submodule, a current control submodule, a coordinate transformation submodule and a sinusoidal pulse width modulation submodule. The speed control submodule is electrically connected to the extended Kalman filter algorithm module, and is used to compare the predicted value and the reference value of the extended Kalman filter algorithm module and output a control signal. The current control submodule is connected to the permanent magnet synchronous motor module, and is used to compare the measured value and the reference value of the permanent magnet synchronous motor and output a control signal. The coordinate transformation submodule is respectively connected to the current control submodule, the extended Kalman filter algorithm module and the sinusoidal pulse width modulation submodule, and is used to perform data transformation between a natural coordinate system, a stationary coordinate system and a synchronous rotating coordinate system. The sinusoidal pulse width modulation submodule is connected to the mixed level inverter, and is used to control the switching state of the mixed level inverter. The extended Kalman filter algorithm module is connected to the speed control submodule, and is used to accurately and real-time estimate the speed of the permanent magnet synchronous motor rotor and the position of the magnetic pole, so as to realize the sensorless control of the permanent magnet synchronous motor; The zero-sequence component module is connected to the sinusoidal pulse width modulation submodule and is used to balance the midpoint voltage of the hybrid level inverter; The hybrid level inverter is connected to the permanent magnet synchronous motor and is used to control the normal operation of the permanent magnet synchronous motor.

2. The hybrid level permanent magnet synchronous motor drive device according to claim 1, characterized in that: The speed control submodule includes a speed comparison subunit and a speed PI regulator; The speed comparison subunit is connected to the extended Kalman filter algorithm module and is used to compare the actual speed estimated by the permanent magnet synchronous motor with a reference speed; The speed PI regulator is electrically connected to the speed comparison subunit and is used to output a reference current of the permanent magnet synchronous motor according to an error between the estimated speed and the reference speed.

3. The hybrid level permanent magnet synchronous motor drive device according to claim 1, characterized in that: The current control submodule includes a current comparison subunit and a current PI regulator; The current comparison subunit is connected to the permanent magnet synchronous motor and is used to compare the actual current of the permanent magnet synchronous motor with a reference current; The current PI regulator is connected to the current comparison subunit and is used to output a current control signal according to an error between an actual current and a reference current.

4. The hybrid level permanent magnet synchronous motor drive device according to claim 1, characterized in that: The coordinate transformation submodule is divided into three different forms of coordinate transformation. Form one transforms the three-phase current and three-phase voltage signals of the motor from the natural coordinate system to the stationary coordinate system, which is used for the calculation of the extended Kalman filter algorithm module. Form two transforms the current value of the stationary coordinate system to the synchronous rotating coordinate system, which is used for the input of the current comparison subunit. Form three transforms the voltage value of the synchronous rotating coordinate system to the stationary coordinate system, which is used for the input of the sinusoidal pulse width modulation submodule.

5. The hybrid level permanent magnet synchronous motor drive device according to claim 1, characterized in that: The hybrid level inverter is connected to the permanent magnet synchronous motor and is used to control the normal operation of the permanent magnet synchronous motor. The right side of the hybrid level inverter is composed of 10 IGBT power elements. The first two bridge arms are composed of 4 IGBT power elements, showing a "T" type connection. The third bridge arm is composed of 2 IGBT power elements, showing a "1" type connection. The left side is connected to the right side by a DC power supply and two electrolytic capacitors with completely equal capacitance values.

6. The hybrid level permanent magnet synchronous motor drive device according to claim 1, characterized in that: The sinusoidal pulse width modulation submodule includes a coordinate transformation submodule and a pulse width modulation algorithm for the mixed-level inverter. The coordinate transformation submodule converts the voltage value of the stationary coordinate system into the natural coordinate system, injects the zero-sequence component, and obtains a three-phase modulation signal. The pulse width modulation algorithm for the mixed-level inverter requires that the first two phases of the modulation signal remain unchanged and the third phase modulation signal is shifted.

7. The hybrid level permanent magnet synchronous motor drive device according to claim 1, characterized in that: The zero-sequence component module is connected to the sinusoidal pulse width modulation submodule. Due to the particularity of the hybrid level inverter structure, the output of the zero-sequence component module is affected by the current of the first two bridge arms and the modulation voltage. The zero-sequence component module is used to balance the midpoint voltage of the hybrid level inverter.

8. The hybrid level permanent magnet synchronous motor drive device according to any one of claims 1 to 7, characterized in that: The hybrid level inverter comprises a first bridge arm, a second bridge arm, and a third bridge arm, and the three-phase winding of the permanent magnet synchronous motor comprises a first terminal, a second terminal, and a third terminal; The first terminal of the permanent magnet synchronous motor is electrically connected to the first bridge arm, the second terminal is electrically connected to the second bridge arm, and the third terminal is electrically connected to the third bridge arm.

9. A control method, characterized in that: The control method comprises: S1. Obtaining the actual speed, magnetic pole position, three-phase current value and three-phase voltage value of the permanent magnet synchronous motor; S2. Obtaining voltage values ​​of two electrolytic capacitors of the hybrid level inverter; S3, comparing the actual speed obtained in step S1 with the reference speed, inputting the error value between the two into the speed PI controller, thereby outputting a q-axis current control reference signal, and setting the d-axis current reference signal to 0; S4, according to the magnetic pole position and three-phase current value obtained in step S1, the actual value of the d-axis current and the actual value of the q-axis current are obtained through coordinate transformation, the actual value of the d-axis current is compared with the d-axis current reference signal, and the error value between the two is input into the d-axis current PI controller, thereby outputting a d-axis voltage signal, the actual value of the q-axis current is compared with the q-axis current reference signal, and the error value between the two is input into the q-axis current PI controller, thereby outputting a q-axis voltage signal; S5, obtaining an α-axis voltage signal and a β-axis voltage signal through coordinate transformation according to the d-axis voltage signal and the q-axis voltage signal obtained in step S4 and the magnetic pole position obtained in step S1; S6, according to the α-axis voltage signal and the β-axis voltage signal obtained in step S5, the two are first transformed into a natural coordinate system in the sinusoidal pulse width modulation submodule to obtain voltage values ​​on the A-axis, the B-axis and the C-axis, and the voltage value of the natural coordinate system is added to the output of the zero-sequence component module as the motor modulation signal, the voltage values ​​of the A-axis and the B-axis are the modulation signals of the first bridge arm and the second bridge arm of the hybrid level inverter, and the voltage value of the C-axis is first translated and then used as the modulation signal of the third bridge arm of the hybrid level inverter; S7, according to the modulation signals of the first bridge arm and the second bridge arm obtained in step S6, the first phase and the second phase current values ​​of step S1, and the voltage values ​​of the two electrolytic capacitors obtained in step S2, these data are substituted into the zero-sequence component calculation formula to obtain the zero-sequence component injection value, and the zero-sequence component injection value will be injected into the modulation signals of the first bridge arm, the second bridge arm and the third bridge arm of the hybrid level inverter to balance the midpoint voltage of the hybrid level inverter; S8. According to the modulation signals obtained in steps S6 and S7, the switching states of the power devices in the hybrid level inverter are controlled by hardware implementation of carrier stacking PWM and two-level SPWM, so as to achieve the purpose of controlling the operation of the motor.

10. The control method according to claim 9, characterized in that: The method for obtaining the actual speed and magnetic pole position of the permanent magnet synchronous motor includes: S1, according to claim 9, the three-phase current value and the three-phase voltage value obtained in step S1 are transformed into a stationary coordinate system to obtain the α-axis current, β-axis current, α-axis voltage, and β-axis voltage; S2, according to the α-axis current, β-axis current, α-axis voltage, and β-axis voltage obtained in step S1 of claim 9, as inputs of an extended Kalman filter algorithm, which estimates the actual speed and magnetic pole position of the permanent magnet synchronous motor based on the mathematical model of the permanent magnet synchronous motor and the input conditions; S3. According to the extended Kalman filter algorithm of step S2 in claim 9, the speed estimation based on the extended Kalman filter algorithm can be applied in complex working environments, and has strong anti-noise and anti-interference capabilities.

11. The control method according to claim 9, characterized in that: The topological structure of the hybrid level inverter is a three-phase T-type inverter main circuit, which is composed of 10 IGBT power elements. The first bridge arm and the second bridge arm each have 4 power switch tubes, and the 4 power switch tubes of each bridge arm are connected in a "T" shape. The third bridge arm has 2 power switch tubes. The first bridge arm, the second bridge arm and the third bridge arm are respectively connected to the U phase, the V phase and the W phase of the motor. The three bridge arms are connected to two electrolytic capacitors with completely equal capacitance values. The hybrid level inverter uses a zero-sequence component injection method to balance the midpoint voltage of the inverter. The midpoint voltage balance problem refers to the fluctuation of the potential at the midpoint connected to the two capacitors at the DC end of the three-level inverter due to charging and discharging. For the hybrid level inverter, the power switches of the first bridge arm and the second bridge arm will affect the midpoint voltage fluctuation when they are turned on.

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