A distributed modular multi-phase motor drive system and control method

Abstract

The present invention provides a distributed modular multiphase motor drive system, comprising: a control master station for generating PWM duty cycle information; a drive slave station for real-time acquisition of the multiphase motor's current and generation of PWM waves. Upon receiving the PWM duty cycle information, the drive slave station generates a power signal for driving the multiphase motor, wherein the number of drive slave stations matches the number of multiphase motors; and an SPI bus for communication between the control master station and the drive slave stations. A feedback synchronization mechanism is established based on the SPI bus to address the issue of PWM cycle synchronization response in asynchronous communication networks involving DSPs and FPGAs. The present invention facilitates phase expansion when the number of phases in a multiphase motor is unknown and addresses the issue of clock synchronization for cascaded servo slave stations, making the multiphase motor control system more flexible, real-time, and reliable.

Description

Technical Field

[0001] The present invention relates to the technical field of multi-phase motor drive system control, and in particular to a distributed modular multi-phase motor drive system and a control method thereof. Background Art

[0002] Due to the long-standing establishment and development of the traditional three-phase power supply system, three-phase motors and their variable-speed drive systems have been widely used in the field of AC electrical transmission. In applications such as metallurgical steel rolling, mine hoisting, locomotive traction, and ship propulsion, the demand for variable-speed transmission power continues to increase. Increasing the number of motor phases and reducing the inverter capacity requirements per phase have gradually become a mainstream solution. Thanks to the widespread use of power electronic inverters, motor drives are no longer restricted by the three-phase power supply system. High-power AC transmission can also be achieved using multi-phase (more than three-phase) inverters. Due to their advantages of low voltage, high power, high reliability, and high control flexibility, multi-phase motors are increasingly used in the AC transmission field.

[0003] Currently, traditional multi-phase motor drive systems have a relatively simple topology, often simply expanding the number of power phases in traditional three-phase AC motor drive circuits. In particular, due to the large number of phases in multi-phase motors, and the variable number of phases in certain operating conditions, fixed hardware systems often cannot meet the requirements. Furthermore, when the drive system needs to expand its phase count, traditional hardware systems may not be suitable. Furthermore, when hardware failures occur in traditional systems, the entire drive power board must be replaced, increasing hardware repair costs.

[0004] In response to the problems of the prior art, the present invention provides a distributed modular multi-phase motor drive system and a control method. Summary of the Invention

[0005] To solve the problems in the prior art, the present invention provides a distributed modular multi-phase motor drive system, the system comprising:

[0006] Control master station, which is used to generate PWM duty cycle information;

[0007] The driving slave station is used to collect the current of the multi-phase motor in real time and generate a PWM wave, and generate a power signal for driving the multi-phase motor after receiving the PWM duty cycle information, wherein the number of the driving slave stations matches the multi-phase motor.

[0008] According to one embodiment of the present invention, the system adopts a distributed master-slave structure, including one control master station and multiple drive slave stations, and the control master station and the multiple drive slave stations are connected in a star shape.

[0009] According to one embodiment of the present invention, the number of the drive slave stations is equal to the number of equivalent motors, which is determined based on the total number of phases of the multi-phase motor. The number of the drive slave stations is calculated using the following formula:

[0010]

[0011] Where y is the number of drive slaves and m is the total number of phases of the multi-phase motor.

[0012] According to one embodiment of the present invention, the control master station includes: a torque distribution module, which determines the target torque output to each equivalent motor based on the number of the equivalent motors and the equal distribution principle.

[0013] According to one embodiment of the present invention, the drive slave station comprises:

[0014] Sensors are used to collect the three-phase current, bus current, and bus DC voltage data of the multi-phase motor in real time;

[0015] an analog-to-digital converter, which is used to perform analog-to-digital conversion on the data transmitted by the sensor to obtain a corresponding digital signal;

[0016] An FPGA, configured to generate the PWM wave and insert a dead time into the PWM wave;

[0017] an intelligent power module connected to the FPGA, and generating the power signal based on the PWM wave with the dead time inserted and the PWM duty cycle information;

[0018] The protection circuit collects overcurrent detection signals and temperature comparison signals, and has overcurrent lockout protection and overtemperature lockout protection.

[0019] According to one embodiment of the present invention, the driving slave station includes: a feedback synchronization module, which is used to shorten or delay the PWM period of the driving slave station according to the compensation time, so that the start time of the PWM period of all the driving slave stations is consistent and the driving slave stations respond synchronously to the PWM period of the control master station.

[0020] According to one embodiment of the present invention, when asynchronous communication is adopted between the control master station and the drive slave station, and the drive slave station starts current sampling in the middle of a PWM cycle, and the control master station interrupts according to a preset frequency to issue a data read instruction to the drive slave station, the feedback synchronization module performs the following steps:

[0021] Mark the start moment of the current PWM cycle as the first moment;

[0022] Marking the moment when the control interruption cycle of the control master station starts as the second moment;

[0023] Mark the end time of current sampling as the third time;

[0024] Marking the moment when the driving slave station receives the data reading instruction as the fourth moment;

[0025] Calculate a time difference between the fourth moment and the second moment, marking the time difference as a first time interval;

[0026] Calculate a time difference between the fourth moment and the first moment, marking the time difference as a second time interval;

[0027] Calculate a time difference between the third moment and the first moment, marking the time difference as a third time interval;

[0028] The compensation time is calculated based on the first time interval, the second time interval, and the third time interval.

[0029] According to one embodiment of the present invention, the feedback synchronization module calculates the compensation time using the following formula:

[0030] compen=T2-T1-T3

[0031] In the formula, compen is the compensation time; T2 is the second time interval; T1 is the first time interval; and T3 is the third time interval.

[0032] According to one embodiment of the present invention, the control master station communicates with the drive slave station via an SPI bus.

[0033] According to another aspect of the present invention, a distributed modular multi-phase motor drive system control method is provided. The method is executed by the system described above, and the method comprises the following steps:

[0034] Generate PWM duty cycle information through the control master station;

[0035] Sending PWM duty cycle information to the driving slave via the SPI bus;

[0036] The current of the multi-phase motor is collected through the driving slave station and the PWM wave is generated. After receiving the PWM duty cycle information, the power signal for driving the multi-phase motor is generated, wherein the number of the driving slave stations matches the multi-phase motor.

[0037] According to another aspect of the present invention, a storage medium is provided, which contains a series of instructions for executing the method steps described above.

[0038] The present invention provides a distributed modular multi-phase motor drive system and control method, which has the following advantages or beneficial effects compared with the prior art:

[0039] (1) Distributed master-slave control: The structure of the entire distributed modular multi-phase motor drive system control method is flexible and easy to maintain and replace. When the required number of phases of the multi-phase motor changes, the main drive slave stations are added or reduced;

[0040] (2) Feedback compensation mechanism: In terms of synchronization, a high-precision synchronization time error compensation mechanism is established between the control master station and the drive slave station through the timestamp feedback mechanism, which can achieve the PWM update cycle of different drive slave stations at the same time, and the synchronization time error is within 50ns;

[0041] (3) Realize real-time, reliability and flexibility, and improve control performance: The information transmission between each node of the system adopts a simple serial communication method to realize the star connection of each drive slave station and the control master station, forming a complete multi-phase motor drive control system. The real-time control work is performed by the control master station, which calculates the corresponding multi-phase motor control algorithm and drives the slave station to output power signals and collect current in real time. It can complete data calculation, send control information, and receive feedback information within the specified time. The controller, actuator and sensor of the slave station must respond quickly.

[0042] Other features and advantages of the present invention will be described in the following description, and some of the contents will become obvious from the description or be understood by practicing the present invention. The purposes and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0044] Figure 1 Shows a structural block diagram of a distributed modular multi-phase motor drive system according to an embodiment of the present invention;

[0045] Figure 2 shows a torque distribution diagram according to an embodiment of the present invention;

[0046] Figure 3 Shows a hardware architecture block diagram of a driver slave station according to an embodiment of the present invention;

[0047] Figure 4 shows a feedback synchronization timing relationship diagram according to an embodiment of the present invention;

[0048] Figure 5 shows a master-slave communication timing relationship diagram according to an embodiment of the present invention;

[0049] Figure 6 A timing diagram of a control master station according to an embodiment of the present invention is shown.

[0050] In the drawings, identical components are denoted by the same reference numerals. The drawings are not drawn to scale. The reference numerals in the drawings have the following meanings: control master 1; drive slave 2; first drive slave 21; second drive slave 22; analog-to-digital converter 202; intelligent power module 204; feedback synchronization module 206; PWM output unit 2031; and dead-zone insertion unit 2032. DETAILED DESCRIPTION

[0051] To make the objectives, technical solutions and advantages of the present invention more clear, embodiments of the present invention are described in further detail below with reference to the accompanying drawings.

[0052] Figure 1 A structural block diagram of a distributed modular multi-phase motor drive system according to an embodiment of the present invention is shown.

[0053] In one embodiment, a distributed modular multiphase motor drive system includes a control master station 1 and drive slave stations 2. The control master station 1 is configured to generate PWM duty cycle information. The drive slave stations 2 are configured to acquire the current of the multiphase motor in real time and generate PWM waves. After receiving the PWM duty cycle information, the drive slave stations 2 generate power signals for driving the multiphase motor. The number of drive slave stations 2 matches the number of multiphase motors. In one embodiment, the multiphase motor is a three-phase permanent magnet synchronous motor or other three-phase motor.

[0054] In one embodiment, a distributed modular multi-phase motor drive system employs a distributed master-slave architecture, comprising a master control station 1 and multiple slave drive stations 2, with the master control station 1 and the multiple slave drive stations 2 connected in a star configuration. Specifically, the distributed master-slave architecture of the master control station 1 and the multiple slave drive stations 2 employs a simple serial communication scheme for information transmission between the various system nodes, achieving a star configuration between the slave drive stations 2 and the master control station 1, thereby forming a complete distributed modular multi-phase motor drive system.

[0055] In one embodiment, the number of the drive slave stations 2 is equal to the number of equivalent motors. The number of equivalent motors is determined based on the total number of phases of the multi-phase motor. The number of the drive slave stations 2 is calculated using the following formula:

[0056]

[0057] Where y is the number of drive slaves 2; m is the total number of phases of the multi-phase motor.

[0058] When expanding the original drive system, the multi-phase motor drive system provided by the present invention can be used to flexibly configure the number of drive slaves without being restricted by the original drive system. For example, a traditional hardware system is used for six-phase motor drive, but when the traditional hardware system needs to be used for a nine-phase motor, the traditional hardware system cannot be directly expanded. When using the multi-phase motor drive system provided by the present invention (one control master station + multiple drive slaves), when used for a six-phase motor, only two drive slaves need to be configured. When an existing system with two drive slaves needs to be used for a nine-phase motor, only one drive slave needs to be added to the existing system, thereby increasing the scalability of the system.

[0059] In addition, the multi-phase motor drive system provided by the present invention can be used in situations where the number of phases of a multi-phase motor is unknown. For example, if the number of phases of the driven motor cannot be determined, then by using the multi-phase motor drive system provided by the present invention, the drive slave stations can be directly added or subtracted based on the design. Traditional hardware systems must know the situation of the driven motor in advance and are difficult to expand.

[0060] In addition, when a certain drive circuit of the motor fails and is damaged in certain cases, if the drive circuit needs to be repaired and replaced in a very short time, the multi-phase motor drive system provided by the present invention has the ability to quickly replace part of the drive circuit. It is only necessary to replace the corresponding broken drive slave station, without replacing the entire drive circuit as in traditional solutions.

[0061] Figure 1 1 shows a system structure diagram including two drive slave stations 2, the two drive slave stations 2 are a first drive slave station 21 and a second drive slave station 22. Figure 1 As shown, the control master station 1 is connected to the first drive slave station 21 and the second drive slave station 22 respectively. The first drive slave station 21 and the second drive slave station 22 respectively output three-phase power signals UVW and ABC to the six-phase motor for driving.

[0062] It should be noted that, in practical applications, the number of the drive slave stations 2 needs to be configured according to the total number of phases of the multi-phase motor, and the present invention does not limit the number of the drive slave stations 2.

[0063] In one embodiment, the control master station 1 and the drive slave station 2 communicate using a high-speed SPI bus. Figure 1As shown, the control master station 1 is connected to the first drive slave station 21 through the chip select interface CS1, and is connected to the second drive slave station 22 through the chip select interface CS2. The control master station 1 is connected to the first drive slave station 21 and the second drive slave station 22 through the clock interface CLK, and the control master station 1 is connected to the first drive slave station 21 and the second drive slave station 22 through the data interface (MOSI, MISO).

[0064] In one embodiment, Figure 1 As shown, the control master station 1 is implemented using DSP. Furthermore, the DSP uses the TMS320LF28335 chip, which has powerful control and signal processing capabilities, can implement complex control algorithms, and has on-chip peripherals for processing encoder signals.

[0065] In one embodiment, Figure 1 As shown, the control master station 1 and the drive slave station 2 are isolated by an isolator.

[0066] Figure 2 A torque distribution diagram according to an embodiment of the present invention is shown.

[0067] In one embodiment, the master control station 1 includes a torque distribution module that determines the target torque output to each equivalent motor based on the number of equivalent motors and the principle of equal distribution, thereby generating PWM duty cycle information. Specifically, the master control station 1 is responsible for running the multi-phase motor control algorithm and external communication. The running control algorithm, based on the characteristics of the multi-phase motor, controls the multi-phase motor as multiple three-phase motors, using equal distribution to output torque.

[0068] like Figure 2 As shown, assuming that the total number of phases of the multi-phase motor is six, the number of equivalent motors is determined to be two according to formula (1). The control master station 1 can control the six-phase motor as two three-phase motors, and output two sets of torque effects using the equalization method.

[0069] like Figure 2 As shown, i d1 and i d2 They are the excitation currents of winding 1 (the winding of the first equivalent motor) and winding 2 (the winding of the second equivalent motor), and here we use i d =0 control mode, i d1 and i d2 The reference values ​​of are all set to 0. q1 and i q2 The target torque is distributed according to the output of the speed loop. The distribution method used is the equal distribution method, i.e. q1 =i q2 =1 / 2*i q_tar .

[0070] like Figure 2 As shown in the figure, multi-phase motors require a large number of current acquisition phases, 6 phases, and high synchronization requirements, and the number of output PWM channels is 12. This is only for dual three-phase motors. If corresponding to motors with more phases, such as 9-phase and 12-phase motors, 9-phase motors need to acquire 9-phase current and output 18-channel PWM waves. 12-phase motors mainly acquire 12-phase current and output 24-channel PWM waves. The large number of acquisition phases, the proportional increase in the number of output PWM waves, and the high current acquisition accuracy requirements make it difficult for the control master station 1 to bear the burden. Therefore, a distributed control structure is needed to enable the drive slave station 2 to share the PWM wave output and phase current acquisition tasks. The communication interface between the control master station 1 and the drive slave station 2 is a high-speed SPI bus.

[0071] Figure 3 A hardware architecture block diagram of a driver slave station according to an embodiment of the present invention is shown.

[0072] In one embodiment, the driving slave station includes: a sensor 201 , an analog-to-digital converter 202 , an FPGA 203 , an intelligent power module 204 , and a protection circuit 205 .

[0073] Sensor 201( Figure 3 The sensor 201 is used to collect the three-phase current, bus current and bus DC voltage data of the multi-phase motor in real time. In one embodiment, the sensor 201 can be a Hall current sensor.

[0074] like Figure 3 As shown, the analog-to-digital converter 202 is used to perform analog-to-digital conversion on the data transmitted from the sensor 201 to obtain a corresponding digital signal. In one embodiment, the analog-to-digital converter 202 uses a high-precision and high-speed ADC, and further, the analog-to-digital converter 202 uses AD7606.

[0075] FPGA203 is used to generate PWM wave and insert dead time in PWM wave. Figure 3 As shown, the FPGA 203 includes a PWM output unit 2031 and a dead zone insertion unit 2032. The PWM output unit 2031 is used to output a PWM wave, and the dead zone insertion unit 2032 is used to insert a dead zone time into the PWM wave.

[0076] like Figure 3 As shown, the intelligent power module 204 is connected to the FPGA 203 and generates a power signal based on the PWM wave with the dead time inserted and the PWM duty cycle information. In one embodiment, the intelligent power module 204 uses an intelligent power module chip (Intelligent Power Module, IPM).

[0077] Protection circuit 205 ( Figure 3 (not shown) collects overcurrent detection signals and temperature comparison signals, and has overcurrent lock protection and overtemperature lock protection.

[0078] In summary, the present invention adopts a distributed multi-phase motor master-slave structure of a control master station 1 + a drive slave station 2. Furthermore, the control master station 1 is responsible for calculating the corresponding multi-phase motor control algorithm and calculating the PWM duty cycle to be output. The drive slave station 2 is responsible for high-precision current acquisition and generation of PWM waves, while generating a power signal to drive the motor.

[0079] For distributed control systems, in terms of synchronization, multiple distributed drive slave stations 2 are connected in a star-shaped manner to form a distributed control network. There is a certain delay in data transmission between nodes, and a unified global clock cannot be used. Therefore, complete synchronization is impossible. A reasonable clock synchronization algorithm must be used to compensate for the system delay.

[0080] Specifically, in a distributed control system, the drive slaves 2 and the control master 1 are connected in a star configuration using shielded copper cables, which introduces a certain amount of data transmission delay. Furthermore, for high-precision motor control systems, strict acquisition timing must be met. PWM sampling must be performed in the middle of the center-aligned PWM cycle, and the PWM comparison count value for the next cycle must be loaded at the end of the current cycle.

[0081] In order to solve the problem of data transmission delay, such as Figure 3 As shown, the driving slave station 2 includes a feedback synchronization module 206, which is used to shorten or delay the PWM cycle of the driving slave station according to the compensation time, so that the starting time of the PWM cycle of all the driving slave stations is consistent and the driving slave stations respond synchronously to the PWM cycle of the control master station.

[0082] When asynchronous communication is used between the control master station 1 and the drive slave station 2, and the drive slave station 2 starts current sampling in the middle of the PWM cycle, and the control master station 1 interrupts according to a preset frequency to send a data read instruction to the drive slave station 2, the feedback synchronization module 206 performs the following steps:

[0083] In step S1, the start time of the current PWM cycle is marked as the first moment. Specifically, the start time of the current PWM cycle in the driving slave 2 is marked as the first moment ( Figure 4 point e).

[0084] In step S2, the moment when the control interrupt cycle of the control master station 1 starts is marked as the second moment. Specifically, the control master station 1 triggers a timer interrupt according to a preset frequency, and then sends a data read instruction to the drive slave station 2. Based on the preset frequency, the drive slave station 2 can determine the moment when the control master station 1 sends the data read instruction, and mark it as the second moment ( Figure 4 Further, the preset frequency is set to 10K.

[0085] In step S3, the current sampling end time is marked as the third time. Specifically, the driving slave 2 will start current sampling at the middle time of the PWM cycle, and when the current sampling ends, it is marked as the third time ( Figure 4 middle g-spot).

[0086] In step S4, the moment when the driver slave station 2 receives the data read instruction is marked as the fourth moment. Specifically, after the control master station 1 sends a data read instruction to the driver slave station 2, it will be transmitted by the cable connecting the control master station 1 and the driver slave station 2. This time interval is relatively short but still cannot be ignored, and this time interval is different for the control master station 1 to read different driver slave stations 2. If the first driver slave station is read first, the time interval is smaller, and if the second driver slave station is read later, the time interval is larger. In addition, after receiving the data read instruction, the driver slave station 2 will immediately respond to the data read instruction and transmit data to the control master station 1. Here, the response time of the driver slave station 2 is considered negligible, that is, the driver slave station 2 transmits data to the control master station 1 at the same time as receiving the data read instruction, which is marked as the fourth moment ( Figure 4 mid-h point).

[0087] In step S5, the time difference between the fourth moment and the second moment is calculated and marked as the first time interval. Figure 4 As shown, the time interval between the calculation driving slave station 2 receiving the data reading instruction and the control master station 1 issuing the data reading instruction is marked as the first time interval T1.

[0088] In step S6, the time difference between the fourth moment and the first moment is calculated and marked as the second time interval. Figure 4 As shown, the time interval between when the slave station 2 receives the data reading instruction and when the current PWM cycle starts is calculated and marked as the second time interval T2. This value is variable and will be affected by various factors.

[0089] In step S7, the time difference between the third moment and the first moment is calculated and marked as the third time interval. Figure 4 As shown, the time interval between the end time of current sampling and the start time of the current PWM cycle is calculated, which is marked as the third time interval T3.

[0090] In one embodiment, T1, T2, and T3 are key data in the entire synchronization process, with a resolution of one thousandth of a PWM cycle count value, and feedback synchronization adjustment is performed based on this data.

[0091] In step S8, the compensation time is calculated based on the first time interval, the second time interval, and the third time interval. In one embodiment, the feedback synchronization module 206 calculates the compensation time using the following formula:

[0092] compen=T2-T1-T3(2)

[0093] Wherein, compen is the compensation time; T2 is the second time interval; T1 is the first time interval; and T3 is the third time interval.

[0094] The purpose of feedback compensation in the present invention is to make the control master station 1 perform a timing interrupt just when the drive slave station 2 completes the phase current sampling, which is reflected in Figure 4 In this case, points f and g must coincide. Therefore, the compensation value is Figure 4 The time interval between points f and g or the time interval between points o and e in the figure is synchronised. Moreover, it is not only the PWM time of both parties that needs to be synchronized, but also the phase relationship.

[0095] Through feedback synchronization compensation, the following effects can be achieved: (1) The start time of the PWM cycle of different slaves is consistent, and the synchronization error is less than 50ns; (2) The sampling trigger moment of the phase current is aligned with the center of the PWM cycle, that is, the sampling is performed at the middle moment of a PWM cycle. (3) T2-T1=T3 (such as Figure 5 shown).

[0096] In summary, the feedback synchronization mechanism operates in two phases. Phase 1, the non-communication phase, occurs when the communication line between the control master 1 and the drive slave 2 is in an "inactive state," meaning no active read communication occurs between the two. Before the drive slave 2 receives its first "read data" signal from the control master 1, it has already begun generating PWM cycles and acquiring current signals. However, at this point, there is a frequency and phase difference between the PWM and control cycles of the drive slave 2 and the control master 1. Phase 2, the feedback synchronization phase, occurs when the drive slave 2 receives its first read command from the control master 1, acquiring T1 for the first time. At this point, the ARR compensation value can be calculated to adjust the ARR. The compensation time is calculated as: compen = T2 - T1 - T3.

[0097] The calculated compensation time is used to shorten and delay the PWM cycle currently driving slave 2 to achieve master-slave synchronization. A special case may occur where, after calculating the compensation time, if the current PWM cycle needs to be shortened but there is insufficient time left in the current PWM cycle, the PWM cycle can be terminated immediately. The remaining uncompensated synchronization error will be compensated using the same mechanism in the next PWM cycle until full synchronization is achieved.

[0098] Figure 6 A timing diagram of a control master station according to an embodiment of the present invention is shown.

[0099] The entire distributed architecture is centered around the clock cycle of control master 1. The cycle count value generated by control master 1 is the ultimate target count. It specifies that control master 1 performs control task calculations and triggers interrupts at a frequency of 10 kHz. During a cycle (100 μs), control master 1 accesses drive slave 2 twice: the first time to read the relevant data signal from drive slave 2, and the second time to write the PWM compare register value to be updated.

[0100] like Figure 6 As shown in the figure, the time consumption of the entire calculation task is required to be less than (half PWM cycle - SPI reading FPGA data consumption - SPI writing FPGA data consumption) to ensure that the PWM data written this time can be updated to the next cycle in time.

[0101] The present invention utilizes a distributed feedback synchronization mechanism to establish a high-precision synchronization time error compensation mechanism between the control master station 1 and the drive slave station 2 via a timestamp feedback mechanism, thereby resolving the PWM cycle synchronization response issue in an asynchronous communication network between the control master station 1 and the drive slave station 2. The present invention can effectively improve the scalability of multi-phase motor control systems, making the control system more flexible, real-time, and reliable. Furthermore, the present invention facilitates phase expansion for multi-phase motors with unknown phase numbers and solves the clock synchronization issue of cascaded servo slaves, making the multi-phase motor control system more flexible, real-time, and reliable.

[0102] The present invention also provides a distributed modular multi-phase motor drive system control method, comprising the following steps: generating PWM duty cycle information by controlling a master station 1; sending the PWM duty cycle information to a drive slave station 2 via an SPI bus; collecting the current of the multi-phase motor by driving the slave station 2 and generating a PWM wave, and generating a power signal for driving the multi-phase motor after receiving the PWM duty cycle information, wherein the number of drive slave stations matches the multi-phase motor.

[0103] The distributed modular multi-phase motor drive system and control method provided by the present invention may also be used in conjunction with a computer-readable storage medium having a computer program stored thereon. The computer program is executed to implement the distributed modular multi-phase motor drive system control method. The computer program is capable of executing computer instructions, which include computer program code. The computer program code may be in source code form, object code form, executable file, or some intermediate form.

[0104] Computer-readable storage media may include: any entity or device that can carry computer program code, recording media, USB flash drives, mobile hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0105] It should be noted that the content contained in computer-readable storage media can be appropriately increased or decreased according to the requirements of legislation and patent practices in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practices, computer-readable storage media do not include electrical carrier signals and telecommunications signals.

[0106] In summary, the present invention provides a distributed modular multi-phase motor drive system and control method, which has the following advantages or beneficial effects compared with the prior art:

[0107] (1) Distributed master-slave control: The structure of the entire distributed modular multi-phase motor drive system control method is flexible and easy to maintain and replace. When the required number of phases of the multi-phase motor changes, the main drive slave stations are added or reduced;

[0108] (2) Feedback compensation mechanism: In terms of synchronization, a high-precision synchronization time error compensation mechanism is established between the control master station and the drive slave station through the timestamp feedback mechanism, which can achieve the PWM update cycle of different drive slave stations at the same time, and the synchronization time error is within 50ns;

[0109] (3) Realize real-time, reliability and flexibility, and improve control performance: The information transmission between each node of the system adopts a simple serial communication method to realize the star connection of each drive slave station and the control master station, forming a complete multi-phase motor drive control system. The real-time control work is performed by the control master station, which calculates the corresponding multi-phase motor control algorithm and drives the slave station to output power signals and collect current in real time. It can complete data calculation, send control information, and receive feedback information within the specified time. The controller, actuator and sensor of the slave station must respond quickly.

[0110] It should be understood that the embodiments disclosed herein are not limited to the specific structures, processing steps, or materials disclosed herein, but should extend to equivalent substitutions of these features understood by those skilled in the relevant art. It should also be understood that the terminology used herein is for the purpose of describing specific embodiments only and is not intended to be limiting.

[0111] In the description of the present invention, unless otherwise specified, "plurality" means two or more; terms such as "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," and "tail" indicate positions or relationships based on those shown in the accompanying drawings. These terms are intended solely to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting the present invention. Furthermore, terms such as "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0112] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integral connection; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0113] References in this specification to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Therefore, appearances of the phrases "one embodiment" or "an embodiment" in various places throughout this specification do not necessarily refer to the same embodiment.

[0114] The embodiments of the present invention are presented for purposes of illustration and description and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those skilled in the art. The embodiments are chosen and described in order to better illustrate the principles of the invention and its practical application and to enable those skilled in the art to understand the invention and design various embodiments with various modifications as suited for specific applications.

[0115] Although the embodiments disclosed herein are as described above, the contents described herein are merely embodiments for facilitating understanding of the present invention and are not intended to limit the present invention. Any person skilled in the art of the present invention may make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed herein. However, the scope of patent protection of the present invention shall still be subject to the scope defined by the appended claims.

Claims

1. A distributed modular multi-phase motor drive system, characterized in that: The system comprises: Control master station, which is used to generate PWM duty cycle information; A drive slave station, which is used to collect the current of the multi-phase motor in real time and generate a PWM wave, and generate a power signal for driving the multi-phase motor after receiving the PWM duty cycle information, wherein the number of the drive slave stations matches the multi-phase motor; The driving slave station includes: a feedback synchronization module, which is used to shorten or delay the PWM cycle of the driving slave station according to the compensation time, so that the start time of the PWM cycle of all the driving slave stations is consistent and the driving slave stations respond synchronously to the PWM cycle of the control master station; When asynchronous communication is adopted between the control master station and the drive slave station, and the drive slave station starts current sampling in the middle of the PWM cycle, and the control master station interrupts according to a preset frequency to issue a data reading instruction to the drive slave station, the feedback synchronization module performs the following steps: Mark the start moment of the current PWM cycle as the first moment; Marking the moment when the control interruption cycle of the control master station starts as the second moment; Mark the end time of current sampling as the third time; Marking the moment when the driving slave station receives the data reading instruction as the fourth moment; Calculate a time difference between the fourth moment and the second moment, marking the time difference as a first time interval; Calculate a time difference between the fourth moment and the first moment, marking the time difference as a second time interval; Calculate a time difference between the third moment and the first moment, marking the time difference as a third time interval; The compensation time is calculated based on the first time interval, the second time interval, and the third time interval.

2. A distributed modular multi-phase motor drive system according to claim 1, characterized in that: The system adopts a distributed master-slave structure, including one control master station and multiple drive slave stations, and the control master station and the multiple drive slave stations are connected in a star shape.

3. The distributed modular multi-phase motor drive system according to claim 1, characterized in that: The number of the drive slave stations is equal to the number of equivalent motors. The number of equivalent motors is determined based on the total number of phases of the multi-phase motor. The number of the drive slave stations is calculated using the following formula: Where y is the number of drive slaves and m is the total number of phases of the multi-phase motor.

4. A distributed modular multi-phase motor drive system according to claim 3, characterized in that: The control master station includes: a torque distribution module, which determines the target torque output to each equivalent motor based on the number of the equivalent motors and the equal distribution principle.

5. The distributed modular multi-phase motor drive system according to claim 1, characterized in that: The drive slave station comprises: Sensors are used to collect the three-phase current, bus current, and bus DC voltage data of the multi-phase motor in real time; an analog-to-digital converter, which is used to perform analog-to-digital conversion on the data transmitted by the sensor to obtain a corresponding digital signal; An FPGA, configured to generate the PWM wave and insert a dead time into the PWM wave; an intelligent power module connected to the FPGA, and generating the power signal based on the PWM wave with the dead time inserted and the PWM duty cycle information; The protection circuit collects overcurrent detection signals and temperature comparison signals, and has overcurrent lockout protection and overtemperature lockout protection.

6. The distributed modular multi-phase motor drive system according to claim 1, characterized in that: The feedback synchronization module calculates the compensation time using the following formula: compen=T2-T1-T3 In the formula, compen is the compensation time; T2 is the second time interval; T1 is the first time interval; and T3 is the third time interval.

7. A distributed modular multi-phase motor drive system according to any one of claims 1 to 6, characterized in that: The control master station communicates with the drive slave station via an SPI bus.

8. A distributed modular multi-phase motor drive system control method, characterized in that: Executed by the system according to any one of claims 1 to 7, the method comprises the following steps: Generate PWM duty cycle information through the control master station; Sending PWM duty cycle information to the driving slave via the SPI bus; The current of the multi-phase motor is collected through the driving slave station and the PWM wave is generated. After receiving the PWM duty cycle information, the power signal for driving the multi-phase motor is generated, wherein the number of the driving slave stations matches the multi-phase motor.

9. A storage medium, characterized in that: It contains a series of instructions for executing the method steps as claimed in claim 8.

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