Magnetic coupling alternating current motor wireless driving system and model prediction comprehensive regulation and control method thereof

Abstract

The invention discloses a magnetic coupling AC motor wireless driving system and a model prediction comprehensive regulation and control method thereof. The system comprises an H-bridge inverter module, a magnetic coupling module, an uncontrolled rectification module, a bus support capacitor, a motor driving module, a driving signal generation module, a current sensor, a position sensor and a controller. The H-bridge inverter module is used for converting the voltage into square wave voltage; the magnetic coupling module realizes energy transmission based on an electromagnetic induction principle; the uncontrolled rectifier module is used for rectifying alternating current into direct current; the bus support capacitor is used for stabilizing bus voltage; the motor driving module is used for converting the direct-current bus voltage on the bus supporting capacitor into phase voltage required by a motor; the motor converts electric energy into mechanical energy; and the controller establishes a cost function and solves an optimal voltage vector in the motor driving module and an optimal conduction angle in the H-bridge inverter module so as to drive the switch-on and switch-off of a switch tube and realize comprehensive regulation and control. The method has the advantages of high power supply reliability and flexibility and the like.

Description

Technical Field

[0001] This invention mainly relates to the field of motor technology, specifically to a magnetically coupled AC motor wireless drive system and its model prediction and integrated control method. Background Technology

[0002] With the rapid development of the economy and society, electricity is increasingly profoundly impacting all aspects of human society. As the central hub of electromechanical energy conversion, electric motors are widely used in intelligent manufacturing, aerospace, new energy vehicles, and rail transportation. Wireless drive systems for electric motors possess advantages such as strong adaptability to harsh environments and high flexibility in motion control, enabling energy transmission across physical barriers. They hold significant research value and broad application prospects in fields such as intelligent manufacturing, new energy vehicles, and special robots.

[0003] The magnetically coupled AC motor wireless drive system utilizes coils in the magnetic coupling mechanism to achieve contactless energy transfer and converts electrical energy into mechanical energy through the motor, enabling highly flexible drive control. For example, in multi-degree-of-freedom motion control systems, replacing the traditional wired power supply motor drive system at the joints with a magnetically coupled AC motor wireless drive system can eliminate the physical constraints of power cables, achieving continuous 360° free rotation and thus improving operational control flexibility. Existing literature generally divides the magnetically coupled AC motor wireless drive system into a wireless power transmission subsystem and a motor drive subsystem, with relatively weak control coupling between the systems. The wireless power transmission subsystem is responsible for closed-loop control of the bus voltage, adjusting the phase shift angle by detecting the difference between the actual and reference values ​​of the bus voltage, thereby regulating the charging current of the bus capacitor; the motor drive subsystem controls the motor speed through dual closed-loop control of speed and current, while the bus capacitor discharges. Under this control method, the charging and discharging power of the bus capacitor is not effectively balanced. When the load on a magnetically coupled AC motor wireless drive system suddenly decreases, the discharge current of the bus capacitor decreases; conversely, when the load suddenly increases, the discharge current of the bus capacitor rapidly increases to a large value. However, since the bus voltage is achieved through closed-loop control of the wireless power transmission subsystem, factors such as the delay in the voltage detection stage and the control parameters of the voltage controller can affect the speed of the bus voltage closed-loop control, causing an imbalance in the charging and discharging current of the bus capacitor. This leads to voltage surges or drops, resulting in a decrease in the control performance and reliability of the motor wireless drive system. Therefore, this study investigates a comprehensive control method for magnetically coupled AC motor wireless drive systems. By combining the control system parameters of the two subsystems and comprehensively considering the coupling correlation of the subsystem control parameters, a model prediction comprehensive control method is constructed to solve the problem of unbalanced charging and discharging power of the bus capacitor. This approach will help promote its application in fields such as multi-degree-of-freedom motion control, hub motors for new energy vehicles, and special robots. Summary of the Invention

[0004] To address the technical problems existing in the prior art, this invention provides a magnetically coupled AC motor wireless drive system and its model prediction integrated control method to improve power supply reliability and flexibility. While improving power supply reliability and flexibility, it also solves the technical problem of unbalanced charging and discharging current of the bus support capacitor.

[0005] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows: A magnetically coupled AC motor wireless drive system includes a DC power supply, a wireless power transmission subsystem, a bus support capacitor, a motor drive module, a drive signal generation module, a current sensor, a position sensor, and a controller. The wireless power transmission subsystem includes an H-bridge inverter module, a magnetic coupling module, and an uncontrolled rectifier module. The motor drive subsystem includes a motor drive module and an AC motor; The input port of the H-bridge inverter module is connected to the DC power supply, and the output port is connected to the input port of the magnetic coupling module; the input port of the uncontrolled rectifier module is connected to the output port of the magnetic coupling module, and the output port is connected to the input port of the bus support capacitor; the input port of the motor drive module is connected to the output terminal of the bus support capacitor, and the output terminal is connected to the motor. The current sensor is located on the motor winding and is used to measure the three-phase current signal of the motor and transmit it to the controller; the position sensor is used to detect the rotor position signal of the motor and transmit it to the controller; the controller is used to calculate the rotor speed and three-phase current of the motor and provide drive control signals to the drive signal generation module. The controller, based on the motor's three-phase current and rotor position signal, combined with the system model and predicted motor d-axis and q-axis currents and bus support capacitor charging and discharging current, establishes a cost function with the objectives of minimizing the motor d-axis and q-axis current control error and balancing the charging and discharging power of the bus support capacitor. It then solves for the optimal voltage vector in the motor drive module and the optimal conduction angle in the H-bridge inverter module, thereby obtaining the drive control signal. This signal is then converted into a drive signal by the drive signal generation module to drive the switching transistors to turn on and off, achieving comprehensive control of the magnetically coupled AC motor wireless drive system.

[0006] Preferably, the H-bridge inverter module is used to convert DC power supply voltage into square wave voltage, and includes a first half-bridge and a second half-bridge, wherein the first half-bridge includes a first upper-side switching transistor. S 1 and the first switching transistor S 2. The second half-bridge includes the second upper switching transistor. S 3 and the second switching transistor S 4; First upper switch transistor S 1 and 2 upper switching transistors SOne end of 3 is connected to the positive terminal of the DC power supply; the first lower switching transistor S 2 and the second lower switch transistor S One end of 4 is connected to the negative terminal of the DC power supply; the first upper switching transistor S 1 and the first switching transistor S The other end of 2 is connected to form a common node A; the second upper switch transistor S 3 and the second switching transistor S The other end of 4 is connected to form a common node B; common node A and common node B are connected to the input end of the magnetic coupling module.

[0007] Preferably, the first open switch tube S 1. First switching transistor S 2. Second upper switch transistor S 3 and the second switching transistor S All four are SiC MOSFETs with anti-parallel diodes.

[0008] Preferably, the magnetic coupling module includes a primary-side compensation capacitor. C 1. Primary coil L 1. Secondary coil L 2 and secondary side compensation capacitor C 2; Primary-side compensation capacitor C 1 and the primary coil L 1. A series circuit is formed on the primary side to create a series resonant circuit, and the primary side compensation capacitor is used. C 1 and the primary coil L 1. The sum of the inductor impedances is zero; secondary-side compensation capacitor C 2 and secondary coil L Two capacitors are connected in series to form a secondary series resonant circuit, with a secondary compensation capacitor. C 2 and secondary coil L 2. The sum of the inductor impedances is zero.

[0009] Preferably, the uncontrolled rectifier module is used to rectify the AC current into DC and to support the bus capacitor. C m Charging, including the first diode D 1. Second diode D 2. Third diode D 3 and the fourth diode D 4; First diode D 1 and the third diode D The negative terminal of diode 3 is connected to one end of the busbar support capacitor; the second diode D 2 and the fourth diode D The positive terminal of diode 4 is connected to the other end of the busbar support capacitor; the first diode D The positive terminal of 1 and the second diode DThe negative terminal of diode 2 is connected to one end of the output of the magnetic coupling module; the third diode... D 3's positive terminal and the fourth diode D The negative terminal of 4 is connected to the other end of the output of the magnetic coupling module.

[0010] This invention also discloses a model prediction integrated control method based on the above-described magnetically coupled AC motor wireless drive system, comprising: Phase shift modulation is used in the H-bridge inverter module. By controlling the phase difference of the drive control signal between the two half-bridges of the H-bridge inverter module, the first bus current is adjusted. I dc1 The input current of the busbar support capacitor is the first busbar current. I dc1 ; For the motor drive module, a combination of speed outer loop and model-predicted current control is used to control the d-axis and q-axis currents of the motor. The motor speed is controlled through dual closed-loop control and space pulse width vector modulation, while the second bus current is acquired. I dc2 The output current of the busbar support capacitor is the second busbar current. I dc2 ; By extending the model to predict current control, a cost function for the capacitor charging current is established, and the corresponding first bus current is calculated. I dc1 Corresponding phase shift angle i f This balances the charging and discharging power of the busbar support capacitor, reducing voltage fluctuations in the busbar support capacitor.

[0011] Preferably, the current of the first busbar is adjusted. I dc1 The specific process is as follows: The first upper switching transistor of the H-bridge inverter module S 1. First switching transistor S The drive control signals of the second transistor are 180° out of phase. S 3 and the second switching transistor S 4. The drive control signals are 180° out of phase to prevent shoot-through in the half-bridge that could cause a power short circuit. H-bridge inverter module first upper switching transistor S 1 and 2 upper switching transistors S The difference between the 3 drive control signals is the phase shift angle θ. f By adjusting i f To adjust the amplitude of the fundamental voltage output of the H-bridge inverter module:

[0012] in, u 1 represents the fundamental voltage output by the H-bridge inverter module. V d This is the DC power supply voltage. oh It is the resonant angular frequency; Based on the transmission characteristics of the magnetic coupling module using a series compensation capacitor, the secondary coil current... i L2 With the fundamental voltage output of the H-bridge inverter module u Proportional to 1, the first bus current I dc1 and i L2 Similarly, the first bus current is directly proportional to the phase shift angle, thus revealing the inherent correspondence between the first bus current and the phase shift angle:

[0013]

[0014] in, i L2 This is the secondary coil current. M The primary and secondary coils are mutually inducted. I dc1 This refers to the current of the first busbar; When adjusting the phase shift angle of the H-bridge inverter module i f At that time, its output fundamental voltage u 1. Change, which in turn makes i L2 and I dc1 The corresponding changes are made to regulate the charging current of the bus capacitor.

[0015] Preferably, for the motor drive module, the d-axis and q-axis currents of the motor are controlled by a combination of speed outer loop and model-predicted current control. The motor speed is controlled through dual closed-loop control and space pulse width vector modulation. The specific process of obtaining the second bus current is as follows: In the outer speed loop, the motor speed is calculated based on the rotor position signal and compared with the speed reference value. A q-axis current reference value is then generated through a proportional-integral controller. i q_ref Simultaneously, the corresponding d-axis current reference value is determined based on the maximum torque-to-current ratio. i d_ref ; In model predictive current control, the actual currents of the motor's d and q axes are calculated through coordinate changes based on the three-phase current information and rotor position information obtained from current sensors. i d andi q We establish cost functions for the d-axis and q-axis currents, solve for the optimal voltage vector that minimizes the cost functions, and achieve fast and accurate control of the motor speed. The three-phase current information includes the motor winding currents of phases A, B, and C. i a , i b and i c The rotor position information is the electrical angle at which the rotor is located. i e d-axis and q-axis current utilization i a , i b , i c and i e Obtained based on Park coordinate transformation; Find the optimal voltage vector that minimizes the cost function. CF 1 can be represented as:

[0016] in i d_next This is the predicted value of the d-axis current; i q_next This is the predicted value for the q-axis current; i d_ref This is the reference value for the d-axis current. i q_ref This is the reference value for the q-axis current.

[0017] Preferably, the voltage is calculated using the following formula based on the motor voltage equation. i d_next and i q_next ;

[0018] Where Δ i d and Δ i d These represent the predicted increments of the d-axis and q-axis currents, respectively. T s For model prediction of control period, u d and u q These are the d-axis and q-axis voltages of the motor, respectively. L d and L q For the d-axis and q-axis inductances of the motor,R For motor phase resistance, ψ f For permanent magnet flux linkage in motors.

[0019] Preferably, by extending the model to predict current control, a cost function for the capacitor charging current is established, which is then used to calculate the phase shift angle corresponding to the first bus current, thereby balancing the charging and discharging power of the bus support capacitor and reducing voltage fluctuations in the bus support capacitor. The specific process is as follows: Extended model predictive current control, which controls the first bus current. I dc1 Second bus current I dc2 The difference is used to obtain the capacitor charging current of the bus support capacitor. i cap A cost function is constructed with the goal of reducing capacitor charging current fluctuations. CF 2. As shown below, find the optimal phase shift angle that minimizes the cost function, thereby minimizing the fluctuation of the capacitor charging current;

[0020] The phase shift angle ranges from [0, 180°], and is divided into n basic phase shift angles. i 1, i 2,…, i n-1 , i n , i 1 = 0° i n =180°; Based on the solved optimal voltage vector and optimal phase shift angle, a corresponding drive control signal is generated and converted into a drive signal by the drive signal generation module to achieve the charging and discharging power balance of the bus support capacitor.

[0021] Compared with the prior art, the advantages of the present invention are as follows: This invention, based on the realization of non-contact motor drive in a wireless motor drive system, utilizes model predictive current control technology to achieve comprehensive system regulation, effectively solving the problem of power imbalance during charging and discharging of the bus support capacitor. This invention proposes to comprehensively consider the control of the H-bridge inverter module and the motor drive module, using model predictive control to achieve comprehensive regulation of the magnetically coupled AC motor wireless drive system. This achieves stable power transmission in all system components and solves the technical problem of power imbalance during charging and discharging of the bus support capacitor. This invention uses model predictive control to predict and control the d-axis and q-axis currents and the capacitor charging current, and uses a cost function to jointly and rapidly select the optimal voltage vector and optimal phase shift angle, achieving current prediction and balance control within a single control cycle, thus improving the system's control speed. Due to the non-contact energy transmission characteristics of the magnetic coupling mechanism in the wireless motor drive system, compared with traditional wired power supply motor drive systems, the magnetically coupled AC motor wireless drive system can achieve power supply across physical barriers, improving the system's power supply reliability and flexibility. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the magnetically coupled AC motor wireless drive system of the present invention.

[0023] Figure 2 This is a flowchart of an embodiment of the model prediction and integrated control method of the present invention.

[0024] Figure 3 This invention relates to the phase shift control method for the H-bridge inverter module.

[0025] Figure 4 These are the eight basic voltage vectors of the motor drive module in this invention.

[0026] Figure 5 The circuit structure and current flow path of the motor drive module are shown in the diagram; where (a) is the circuit structure of the motor drive module; and (b) is the voltage vector. V 0 and V 7. Current flow path of the motor drive module under action; (c) is the voltage vector. V 3. Current flow path of the motor drive module under action; (d) is the voltage vector. V 4. Current flow path of the motor drive module under action; (e) is the voltage vector. V 2. Current flow path of the motor drive module under action; (f) is the voltage vector. V 5. Current flow path of the motor drive module under action; (g) is the voltage vector. V The current flow path of the motor drive module under the action of 1; (h) is the voltage vector. V The current flow path of the motor drive module under the action of 6. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0028] like Figure 1 As shown, the magnetic coupling AC motor wireless drive system provided in this embodiment of the invention includes: a DC power supply, a wireless power transmission subsystem, a bus support capacitor, a motor drive subsystem, a drive signal generation module, a current sensor, a position sensor, and a controller. The wireless power transmission subsystem includes: an H-bridge inverter module, a magnetic coupling module, and an uncontrolled rectifier module; The motor drive subsystem includes: a motor drive module and an AC motor; The input port of the H-bridge inverter module is connected to the DC power supply, and the output port is connected to the input port of the magnetic coupling module; the input port of the uncontrolled rectifier module is connected to the output port of the magnetic coupling module, and the output port is connected to the input port of the bus support capacitor; the input port of the motor drive module is connected to the output terminal of the bus support capacitor, and the output terminal is connected to the motor. The current sensor is located in the motor winding and is used to measure the three-phase current signal of the motor and transmit it to the controller; the position sensor is used to detect the rotor position signal of the motor and transmit it to the controller; the controller is used to calculate the rotor speed and three-phase current of the motor and provide drive control signals to the drive signal generation module. The controller establishes a cost function based on the motor's three-phase current and rotor position signal, combined with the system model and predicted motor d-axis and q-axis currents and bus support capacitor charging and discharging currents. The goal is to minimize the motor's d-axis and q-axis control errors and balance the charging and discharging power of the bus support capacitors. The controller then solves for the optimal voltage vector in the motor drive module and the optimal conduction angle in the H-bridge inverter module, thereby obtaining the drive control signal. This signal is then converted into a drive signal by the drive signal generation module to drive the switching transistors to turn on and off, achieving comprehensive control of the magnetically coupled AC motor wireless drive system.

[0029] Specifically, the H-bridge inverter module converts DC power supply voltage into square wave voltage, and includes a first half-bridge and a second half-bridge, wherein the first half-bridge includes a first upper-side switching transistor. S 1 and the first switching transistor S 2. The second half-bridge includes the second upper switching transistor. S 3 and the second switching transistor S 4; First upper switching transistor S 1 and 2 upper switching transistors S One end of 3 is connected to the positive terminal of the DC power supply; the first switching transistor S 2 and the second lower switch transistor S One end of 4 is connected to the negative terminal of the DC power supply; the first upper switching transistor S 1 and the first switching transistorS The other end of 2 is connected to form a common node A; the second upper switch transistor S 3 and the second switching transistor S The other end of 4 is connected to form a common node B; common node A and common node B are connected to the input end of the magnetic coupling module.

[0030] The first one is open to the control. S 1. First switching transistor S 2. Second upper switch transistor S 3 and the second switching transistor S All four are SiC MOSFETs with anti-parallel diodes.

[0031] Specifically, the magnetic coupling module includes a primary-side compensation capacitor. C 1. Primary coil L 1. Secondary coil L 2 and secondary side compensation capacitor C 2. Energy transfer is achieved through series resonance based on the principle of electromagnetic induction; primary-side compensation capacitor. C 1 and the primary coil L 1. A series connection forms a primary-side series resonant circuit, with a primary-side compensation capacitor. C 1 and the primary coil L 1. The sum of the inductor impedances is zero; secondary-side compensation capacitor C 2 and secondary coil L 2 are connected in series to form a secondary series resonant circuit, and the secondary compensation capacitor... C 2 and secondary coil L 2. The sum of the inductor impedances is zero.

[0032] Specifically, the uncontrolled rectifier module is used to rectify AC current into DC and to support the bus capacitor. C m Charging, including the first diode D 1. Second diode D 2. Third diode D 3 and the fourth diode D 4; First diode D 1 and the third diode D The negative terminal of diode 3 is connected to one end of the busbar support capacitor; the second diode D 2 and the fourth diode D The positive terminal of diode 4 is connected to the other end of the busbar support capacitor; the first diode D The positive terminal of 1 and the second diode D The negative terminal of diode 2 is connected to one end of the output of the magnetic coupling module; the third diode... D 3's positive terminal and the fourth diode D The negative terminal of 4 is connected to the other end of the output of the magnetic coupling module.

[0033] Specifically, busbar support capacitor C m Used to stabilize the bus voltage, its input current is the first bus current. I dc1 The output current is the second bus current. I dc2 First bus current I dc1 Second bus current I dc2 The difference is the capacitor charging current. i cap The motor drive module is used to power the bus support capacitor. C m The DC bus voltage is converted into the phase voltage required by the motor; the motor converts electrical energy into mechanical energy, including the three-phase windings, stator, and rotor structure.

[0034] Due to the non-contact energy transmission characteristics of the magnetic coupling mechanism in the wireless motor drive system, compared with the traditional wired power supply motor drive system, the magnetic coupling AC motor wireless drive system can achieve power supply across physical barriers, improving the system's power supply reliability and flexibility.

[0035] like Figure 2 As shown, the model prediction and integrated control method for a magnetically coupled AC motor wireless drive system provided in this embodiment of the invention includes: Phase Shift Modulation (PSM) is used on the H-bridge inverter module to adjust the first bus current by controlling the phase difference of the drive control signal between the two half-bridges of the H-bridge inverter module. For the motor drive module, the d-axis and q-axis currents of the motor are controlled by a combination of speed outer loop and model prediction current control. The motor speed is controlled by dual closed-loop control and space vector pulse width modulation (SVPWM), while the second bus current is obtained. By extending the model to predict current control, a cost function for capacitor charging current is established, and the phase shift angle corresponding to the first bus current is derived and calculated, thereby balancing the charging and discharging power of the bus support capacitor and reducing voltage fluctuations of the bus support capacitor.

[0036] Specifically, phase shift modulation (PSM) is applied to the H-bridge inverter module. By controlling the phase difference of the drive control signal between the two half-bridges of the H-bridge inverter module, the first bus current is adjusted, including: H-bridge inverter module first upper switching transistor S 1. First switching transistorS The drive control signals of the second transistor are 180° out of phase. S 3 and the second switching transistor S 4. The drive control signals are 180° out of phase to prevent shoot-through in the half-bridge that could cause a power short circuit. H-bridge inverter module first upper switching transistor S 1 and 2 upper switching transistors S The difference between the 3 drive control signals is the phase shift angle θ. f By adjusting i f To adjust the amplitude of the fundamental voltage output of the H-bridge inverter module:

[0037] in, u 1 represents the fundamental voltage output by the H-bridge inverter module. V d This is the DC power supply voltage. oh It is the resonant angular frequency.

[0038] Figure 3 This demonstrates the phase shift control method for the H-bridge inverter module, where the phase shift angle... i f From reduced to i f 'hour, S 1 and S 4. The opening time is shortened. u 1 becomes smaller, thus making i L1 and I dc1 Decrease; conversely, when the conduction angle i f When it increases, I dc1 Increase.

[0039] Based on the transmission characteristics of the magnetic coupling module using a series compensation capacitor, the secondary coil current... i L2 With the fundamental voltage output of the H-bridge inverter module u Proportional to 1, the first bus current I dc1 and i L2 Similarly, the first bus current is directly proportional to the phase shift angle, thus revealing the inherent correspondence between the first bus current and the phase shift angle:

[0040]

[0041] in, iL2 This is the secondary coil current. M The primary and secondary coils are mutually inducted. I dc1 This is the current of the first bus. As can be seen from the formula, when the phase shift angle of the H-bridge inverter module is adjusted... i f At that time, its output fundamental voltage u 1, thereby enabling i L2 and I dc1 The corresponding changes are made to regulate the charging current of the bus capacitor.

[0042] Specifically, for the motor drive module, the d-axis and q-axis currents of the motor are controlled by a combination of speed outer loop and model-predicted current control. The motor speed is controlled through dual closed-loop control and space vector pulse width modulation (SVPWM). The specific process of obtaining the second bus current is as follows: In the outer speed loop, the motor speed is calculated based on the rotor position signal and compared with the speed reference value. A q-axis current reference value is then generated through a proportional-integral controller. i q_ref Simultaneously, the corresponding d-axis current reference value is determined based on the maximum torque-to-current ratio. i d_ref ; In model predictive current control, the actual currents of the motor's d and q axes are calculated through coordinate changes based on the three-phase current information and rotor position information obtained from current sensors. i d and i q We establish cost functions for the d-axis and q-axis currents, solve for the optimal voltage vector that minimizes the cost functions, and achieve fast and accurate control of the motor speed. The three-phase current information includes the motor winding currents of phases A, B, and C. i a , i b and i c The rotor position information is the electrical angle at which the rotor is located. i e d-axis and q-axis current utilization i a , i b , i c and i e Obtained from Park coordinate transformation; the voltage vector includes two zero vectors. V0 and V 7, and six non-zero voltage vectors V 1. V 2. V 3. V 4. V 5 and V 6. The eight basic voltage vectors of the motor drive module are as follows: Figure 4 As shown, V 0 to V 7 is represented by (000), (100), (110), (010), (011), (001), (101), (111), respectively. The number 1 indicates that the upper switch tube of the bridge arm is turned on and the lower switch tube is turned off, and the number 0 indicates that the lower switch tube of the bridge arm is turned on and the upper switch tube is turned off. Find the optimal voltage vector that minimizes the cost function. CF 1 can be represented as:

[0043] in i d_next This is the predicted value of the d-axis current. i q_next This is the predicted value for the q-axis current; i d_next and i q_next The value is calculated using the following formula based on the motor voltage equation;

[0044] Where Δ i d and Δ i d These represent the predicted increments of the d-axis and q-axis currents, respectively. T s For model prediction of control period, u d and u q These are the d-axis and q-axis voltages of the motor, respectively. L d and L q For the d-axis and q-axis inductances of the motor, R For motor phase resistance, ψ f For permanent magnet flux linkage in motors; Figure 5 (a) is a schematic diagram of the circuit structure of the motor drive module. Figure 5 Figures (b) to (h) illustrate the current flow paths of the motor drive module under different voltage vectors, for example, Figure 5In (c) when the voltage vector V When 3(010) is activated, the lower switches of phases A and C are turned on, the upper switch of phase B is turned on, and the second bus current... I dc2 With phase B current i b Similarly, based on the voltage vector selection result, the on / off state and current flow path of each switch in the motor drive module are determined, and the second bus current is obtained by combining the motor phase current information. I dc2 :

[0045] Specifically, by extending the model to predict current control, a cost function for the capacitor charging current is established, which is then used to calculate the phase shift angle corresponding to the first bus current. This balances the charging and discharging power of the bus support capacitor and reduces voltage fluctuations in the bus support capacitor. Extended model predictive current control, which controls the first bus current. I dc1 Second bus current I dc2 The difference is used to obtain the capacitor charging current of the bus support capacitor. i cap A cost function is constructed with the goal of reducing capacitor charging current fluctuations. CF 2. As shown below, find the optimal phase shift angle that minimizes the cost function, thereby minimizing the fluctuation of the capacitor charging current;

[0046] The phase shift angle ranges from [0, 180°], and is divided into n basic phase shift angles ( i 1, i 2,…, i n-1 , i n ), i 1 = 0° i n =180°; Based on the solved optimal voltage vector and optimal phase shift angle, a corresponding drive control signal is generated and converted into a drive signal by the drive signal generation module to achieve the charging and discharging power balance of the bus support capacitor.

[0047] This invention, based on the realization of non-contact motor drive in a wireless motor drive system, utilizes model predictive current control technology to achieve comprehensive system regulation, effectively solving the problem of power imbalance during charging and discharging of the bus support capacitor. This invention proposes to comprehensively consider the control of the H-bridge inverter module and the motor drive module, using model predictive control to achieve comprehensive regulation of the magnetically coupled AC motor wireless drive system. This ensures stable power transmission in all system components and solves the technical problem of power imbalance during charging and discharging of the bus support capacitor. Furthermore, this invention uses model predictive control to predict and control the d-axis and q-axis currents and the capacitor charging current, and uses a cost function to jointly and rapidly select the optimal voltage vector and optimal phase shift angle, achieving current prediction and balance control within a single control cycle, thus improving the speed of system control.

[0048] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A wireless drive system for a magnetically coupled AC motor, characterized in that, It includes a DC power supply, a wireless power transmission subsystem, a bus support capacitor, a motor drive module, a drive signal generation module, a current sensor, a position sensor, and a controller. The wireless power transmission subsystem includes an H-bridge inverter module, a magnetic coupling module, and an uncontrolled rectifier module. The motor drive subsystem includes a motor drive module and an AC motor; The input port of the H-bridge inverter module is connected to the DC power supply, and the output port is connected to the input port of the magnetic coupling module; the input port of the uncontrolled rectifier module is connected to the output port of the magnetic coupling module, and the output port is connected to the input port of the bus support capacitor; the input port of the motor drive module is connected to the output terminal of the bus support capacitor, and the output terminal is connected to the motor. The current sensor is located on the motor winding and is used to measure the three-phase current signal of the motor and transmit it to the controller; the position sensor is used to detect the rotor position signal of the motor and transmit it to the controller; the controller is used to calculate the rotor speed and three-phase current of the motor and provide drive control signals to the drive signal generation module. The controller, based on the motor's three-phase current and rotor position signal, combined with the system model and predicted motor d-axis and q-axis currents and bus support capacitor charging and discharging current, establishes a cost function with the objectives of minimizing the motor d-axis and q-axis current control error and balancing the charging and discharging power of the bus support capacitor. It then solves for the optimal voltage vector in the motor drive module and the optimal conduction angle in the H-bridge inverter module, thereby obtaining the drive control signal. This signal is then converted into a drive signal by the drive signal generation module to drive the switching transistors to turn on and off, achieving comprehensive control of the magnetically coupled AC motor wireless drive system.

2. The magnetically coupled AC motor wireless drive system according to claim 1, characterized in that, The H-bridge inverter module is used to convert DC power supply voltage into square wave voltage, and includes a first half-bridge and a second half-bridge, wherein the first half-bridge includes a first upper switching transistor. S 1 and the first switching transistor S 2. The second half-bridge includes the second upper switching transistor. S 3 and the second switching transistor S 4; First upper switch transistor S 1 and 2 upper switching transistors S One end of 3 is connected to the positive terminal of the DC power supply; the first lower switching transistor S 2 and the second lower switch transistor S One end of 4 is connected to the negative terminal of the DC power supply; the first upper switching transistor S 1 and the first switching transistor S The other end of 2 is connected to form a common node A; the second upper switch transistor S 3 and the second switching transistor S The other end of 4 is connected to form a common node B; common node A and common node B are connected to the input end of the magnetic coupling module.

3. The magnetically coupled AC motor wireless drive system according to claim 2, characterized in that, First switch S 1. First switching transistor S 2. Second upper switch transistor S 3 and the second switching transistor S All four are SiC MOSFETs with anti-parallel diodes.

4. The magnetically coupled AC motor wireless drive system according to claim 1, 2, or 3, characterized in that, The magnetic coupling module includes a primary-side compensation capacitor. C 1. Primary coil L 1. Secondary coil L 2 and secondary side compensation capacitor C 2; Primary-side compensation capacitor C 1 and the primary coil L 1. A series circuit is formed on the primary side to create a series resonant circuit, and the primary side compensation capacitor is used. C 1 and the primary coil L 1. The sum of the inductor impedances is zero; secondary-side compensation capacitor C 2 and secondary coil L Two capacitors are connected in series to form a secondary series resonant circuit, with a secondary compensation capacitor. C 2 and secondary coil L 2. The sum of the inductor impedances is zero.

5. The magnetically coupled AC motor wireless drive system according to claim 1, 2, or 3, characterized in that, Uncontrolled rectifier modules are used to rectify AC current into DC and provide bus support capacitors. C m Charging, including the first diode D 1. Second diode D 2. Third diode D 3 and the fourth diode D 4; First diode D 1 and the third diode D The negative terminal of diode 3 is connected to one end of the busbar support capacitor; the second diode D 2 and the fourth diode D The positive terminal of diode 4 is connected to the other end of the busbar support capacitor; the first diode D The positive terminal of 1 and the second diode D The negative terminal of diode 2 is connected to one end of the output of the magnetic coupling module; the third diode... D 3's positive terminal and the fourth diode D The negative terminal of 4 is connected to the other end of the output of the magnetic coupling module.

6. A model prediction and integrated control method for a magnetically coupled AC motor wireless drive system according to any one of claims 1-5, characterized in that, include: Phase shift modulation is used in the H-bridge inverter module. By controlling the phase difference of the drive control signal between the two half-bridges of the H-bridge inverter module, the first bus current is adjusted. I dc1 The input current of the busbar support capacitor is the first busbar current. I dc1 ; For the motor drive module, a combination of speed outer loop and model-predicted current control is used to control the d-axis and q-axis currents of the motor. The motor speed is controlled through dual closed-loop control and space pulse width vector modulation, while the second bus current is acquired. I dc2 The output current of the busbar support capacitor is the second busbar current. I dc2 ; By extending the model to predict current control, a cost function for the capacitor charging current is established, and the corresponding first bus current is calculated. I dc1 Corresponding phase shift angle θ f This balances the charging and discharging power of the busbar support capacitor, reducing voltage fluctuations in the busbar support capacitor.

7. The model prediction integrated control method according to claim 6, characterized in that, Adjusting the current of the first bus I dc1 The specific process is as follows: The first upper switching transistor of the H-bridge inverter module S 1. First switching transistor S The drive control signals of the second transistor are 180° out of phase. S 3 and the second switching transistor S 4. The drive control signals are 180° out of phase to prevent shoot-through in the half-bridge that could cause a power short circuit. H-bridge inverter module first upper switching transistor S 1 and 2 upper switching transistors S The difference between the 3 drive control signals is the phase shift angle θ. f By adjusting θ f To adjust the amplitude of the fundamental voltage output of the H-bridge inverter module: in, u 1 represents the fundamental voltage output by the H-bridge inverter module. V d This is the DC power supply voltage. ω It is the resonant angular frequency; Based on the transmission characteristics of the magnetic coupling module using a series compensation capacitor, the secondary coil current... i L2 With the fundamental voltage output of the H-bridge inverter module u Proportional to 1, the first bus current I dc1 and i L2 Similarly, the first bus current is directly proportional to the phase shift angle, thus revealing the inherent correspondence between the first bus current and the phase shift angle: in, i L2 This is the secondary coil current. M The primary and secondary coils are mutually inducted. I dc1 This refers to the current of the first busbar; When adjusting the phase shift angle of the H-bridge inverter module θ f At that time, its output fundamental voltage u 1. Change, which in turn makes i L2 and I dc1 The corresponding changes are made to regulate the charging current of the bus capacitor.

8. The model prediction integrated control method according to claim 6, characterized in that, For the motor drive module, the d-axis and q-axis currents of the motor are controlled by a combination of speed outer loop and model-predicted current control. The motor speed is controlled through dual closed-loop control and space pulse width vector modulation. The specific process of obtaining the second bus current is as follows: In the outer speed loop, the motor speed is calculated based on the rotor position signal and compared with the speed reference value. A q-axis current reference value is then generated through a proportional-integral controller. i q_ref Simultaneously, the corresponding d-axis current reference value is determined based on the maximum torque-to-current ratio. i d_ref ; In model predictive current control, the actual currents of the motor's d and q axes are calculated through coordinate changes based on the three-phase current information and rotor position information obtained from current sensors. i d and i q We establish cost functions for the d-axis and q-axis currents, solve for the optimal voltage vector that minimizes the cost functions, and achieve fast and accurate control of the motor speed. The three-phase current information includes the motor winding currents of phases A, B, and C. i a , i b and i c The rotor position information is the electrical angle at which the rotor is located. θ e d-axis and q-axis current utilization i a , i b , i c and θ e Obtained based on Park coordinate transformation; Find the optimal voltage vector that minimizes the cost function. CF 1 can be represented as: in i d_next This is the predicted value of the d-axis current; i q_next This is the predicted value for the q-axis current. i d_ref This is the reference value for the d-axis current. i q_ref This is the reference value for the q-axis current.

9. The model-predictive integrated control method according to claim 8, characterized in that, Based on the motor voltage equation, the following formula can be used to calculate... i d_next and i q_next ; Where Δ i d and Δ i d These represent the predicted increments of the d-axis and q-axis currents, respectively. T s For model prediction of control period, u d and u q These are the d-axis and q-axis voltages of the motor, respectively. L d and L q For the d-axis and q-axis inductances of the motor, R For motor phase resistance, ψ f For permanent magnet flux linkage in motors.

10. The model prediction integrated control method according to any one of claims 6-9, characterized in that, By extending the model to predict current control, a cost function for the capacitor charging current is established, which is then used to calculate the phase shift angle corresponding to the first bus current. This process balances the charging and discharging power of the bus support capacitor and reduces voltage fluctuations in the bus support capacitor. Extended model predictive current control, controlling the first bus current I dc1 Second bus current I dc2 The difference is used to obtain the capacitor charging current of the bus support capacitor. i cap A cost function is constructed with the goal of reducing capacitor charging current fluctuations. CF 2. As shown below, find the optimal phase shift angle that minimizes the cost function, thereby minimizing the fluctuation of the capacitor charging current; The phase shift angle ranges from [0, 180°], and is divided into n basic phase shift angles. θ 1, θ 2,…, θ n-1 , θ n , θ 1 = 0° θ n =180°; Based on the solved optimal voltage vector and optimal phase shift angle, a corresponding drive control signal is generated and converted into a drive signal by the drive signal generation module to achieve the charging and discharging power balance of the bus support capacitor.

Images