Permanent magnet synchronous motor control system and control method based on field orientation

Abstract

The invention discloses a permanent magnet synchronous motor control system and method based on field orientation, and belongs to the field of motor control. Vector control and direct torque control motor methods have the problem of poor control precision. The invention discloses a permanent magnet synchronous motor control system and control method based on field orientation. The system comprises a power supply module for supplying power to a DSP control module and a motor driving module; the FOC control module is connected with the PWM module, the on-chip ADC and the input capture module; the PWM module is connected with a motor driving chip and a peripheral circuit of the motor driving module, the on-chip ADC is connected with the I-V conversion circuit, and the I-V conversion circuit is connected with the three-phase inverter; the input capture module is connected with the speed measurement encoder; the IIC module is connected with the display driving chip and the nixie tube; and the serial hole communication module is connected with an upper computer. The response speed and stability of the permanent magnet synchronous motor under the dynamic load are improved. By optimizing a motor control strategy, such as maximum torque / ampere control and maximum efficiency control, the energy utilization rate of the motor is improved, and energy consumption is reduced.

Description

Technical Field

[0001] The present invention relates to a control system and method of a permanent magnet synchronous motor, and in particular to a control system and a control method of a permanent magnet synchronous motor based on magnetic field orientation. Background Art

[0002] In industrial production, motors are widely used in various equipment and systems as core components: in the machinery manufacturing industry, motor control is used to drive and control various mechanical equipment, such as machine tools, conveying equipment, aircraft, etc.; in automated production lines, motor control is used to realize the automated assembly, transportation and packaging of products; in the field of transportation, motor control is used for the power systems of vehicles such as automobiles, trains, and ships; in the field of energy, motor control is used for various energy conversion equipment such as wind power generation, solar power generation, and hydropower generation. With the continuous deepening of intelligent manufacturing and industrial automation, motor control technology will usher in more development opportunities and challenges, and become an important force to promote industrial transformation and upgrading. Compared with traditional induction motors, permanent magnet synchronous motors (PMSMs) have the advantages of high efficiency, high power density, high starting torque and a wide speed regulation range. They can replace induction motors and be widely used in electric vehicles, wind power generation and other fields, and can effectively promote energy conservation, emission reduction and environmental protection development. In addition, the permanent magnet synchronous motor control system can achieve high-precision position and speed control, and can be applied to robots, CNC machine tools, automated production lines and other fields to promote the development of industrial automation and intelligent manufacturing.

[0003] In recent years, with the rise of new energy vehicles and smart homes, the demand for permanent magnet synchronous motors has further increased, but the excellent performance of permanent magnet synchronous motors requires the use of advanced control algorithms for speed regulation and positioning control. The system involves all aspects of motor control, including motor model establishment, control algorithm design, hardware implementation, etc. Therefore, studying permanent magnet synchronous motor control systems can also expand the research and application scope of motor control technology and promote the development of motor control technology.

[0004] The optimization of the control system of permanent magnet synchronous motor is an important direction in the study of permanent magnet synchronous motor, with the focus on the study of its control algorithm. In order to better control permanent magnet synchronous motor, researchers are developing new control algorithms and technologies, which can achieve high efficiency and high performance of the motor and adapt to different working conditions and load changes. Vector control and direct torque control are two common control methods to improve system performance. Among them, vector control uses rotor flux for orientation, while direct torque control achieves performance improvement by orienting the stator flux.

[0005] However, the PI controllers in the vector control system are independent of each other and cannot be used together, which has a great impact on the overall optimization of the system. Vector control is difficult to meet the multi-objective control requirements in the application of controlling permanent magnet synchronous motors. It requires multiple coordinate transformations and has the problem of difficulty in satisfying constraints. Therefore, the vector control effect will be subject to certain restrictions, the calculation time will be long, and there will be more complex calculations during the tuning process. These will affect the response speed of the system, so that the dynamic performance of the system cannot achieve the expected purpose. Similarly, due to its nonlinear control characteristics, the direct torque control scheme causes the frequency at the motor output to be unfixed, which ultimately leads to a large amount of calculation and slow calculation speed in highly intensive calculations, especially when the motor rotates at low speed, which reduces the accuracy of the output voltage model, and the optimal vector output by the hysteresis comparator will cause torque fluctuations. Due to the frequent fluctuations in the switching frequency, it is difficult to use in situations with high control requirements.

[0006] Therefore, the above methods will have different effects on the improvement of motor control performance. No matter which control strategy is adopted, there are certain limitations in the control of permanent magnet synchronous motors. For this reason, researchers at home and abroad have studied it for many years and applied the research results to various occasions.

[0007] The present invention focuses on the key points of permanent magnet synchronous motor control systems, mainly studies the precise control of motor rotation speed and position, learns from the advantages and disadvantages of existing permanent magnet synchronous motor control systems, improves the defects, and designs a permanent magnet synchronous motor control system with stable speed control and accurate position control, mainly including the design of the hardware platform and the study of the control algorithm. Summary of the invention

[0008] The purpose of the present invention is to solve the problem of poor control accuracy in existing vector control and direct torque control motor methods, and to propose a permanent magnet synchronous motor control system and method based on magnetic field orientation.

[0009] The above purpose is achieved through the following technical solutions:

[0010] A permanent magnet synchronous motor control system based on magnetic field orientation, which comprises: a power module, a DSP control module, a motor drive module, a display drive chip and a digital tube and a host computer;

[0011] The DSP control module integrates FOC control module, IIC module, serial communication module, PWM module, on-chip ADC and input capture module;

[0012] The motor drive module integrates a motor drive chip, peripheral circuits and a three-phase inverter, and the motor drive chip and the peripheral circuits are connected to the three-phase inverter;

[0013] The power module supplies power to the DSP control module and the motor drive module; the FOC control module is connected to the PWM module, the on-chip ADC and the input capture module; the PWM module is connected to the motor drive chip and peripheral circuits of the motor drive module, the on-chip ADC is connected to the IV conversion circuit, and the IV conversion circuit is connected to the three-phase inverter; the input capture module is connected to the speed encoder; the IIC module is connected to the display driver chip and the digital tube; the serial communication module is connected to the host computer;

[0014] The DSP control module uses a digital signal processor DSP as the main control chip.

[0015] Furthermore, the three-phase inverter includes three groups of MOS tubes, and only one of the upper and lower tubes of each group of MOS tubes is turned on and the other is turned off at the same time.

[0016] A method for controlling a permanent magnet synchronous motor based on magnetic field orientation using the system described in any of the above claims, collecting the three-phase current of the permanent magnet synchronous motor PMSM, the three-phase current is transformed by Clark and Park to obtain an easy-to-process current signal, compared with the set current value, and the error is input into two controllers to obtain a control voltage, and then the voltage for synthesizing a voltage vector is obtained by Park inverse transformation, which is input into a PWM module to obtain the three-phase voltage of the drive motor module through calculation, thereby completing the control process of the current loop; wherein, the set value of the current is obtained by the speed loop, the encoder on the motor measures the motor speed, and compares it with the set speed, the error obtained is input into the speed regulator, and the output result is the set value of the current and is sent to the current loop; similarly, the set value of the speed is obtained by the position loop, and a complete three-loop control process is obtained.

[0017] Furthermore, the Clark transformation is specifically:

[0018] The three current directions of the motor differ by 120° and are non-orthogonal. In the two-dimensional coordinate system, the new rectangular coordinate system is named α-β coordinate, and the three-phase current is orthogonalized to α-β coordinate, and the coordinate projection calculation is performed;

[0019] The current in the α-β coordinate is calculated by the following formula:

[0020]

[0021] I α and I β It is a virtual variable. After a set of currents are calculated, it is transformed back through the inverse transformation formula of the above formula and then applied to the three phases of the motor.

[0022] Furthermore, the Park transformation is specifically:

[0023] Park transformation is the process of coordinate projection. The angle θ is the angle of rotation of the motor rotor. The transformation formula is:

[0024] I D =cos(θ)I α +sin(θ)I β

[0025] I β = -sin(θ)I α +cos(θ)I β

[0026] The transformed DQ coordinate system rotates with the rotor, and the angle is obtained by the encoder input on the motor. After transformation, the uniformly rotating vector becomes a constant value, and both control variables are linearized, with I D and I Q These two values ​​are the objects of feedback control and are implemented through a linear controller.

[0027] Furthermore, the process of the FOC control target is that, in the above Park transformation, the DQ coordinate system follows the rotor rotation to decompose the rotor flux into variables in the radial and tangential directions of the rotor rotation by decoupling, wherein I Q It is the required current, which represents the output of torque. In the three-loop control, the output through the speed loop control is I Q , I D The setting value I D _ R ef is zero during the entire control process.

[0028] The beneficial effects of the present invention are:

[0029] The present invention designs a suitable parameter adjustment strategy in the FOC algorithm to improve the response speed and stability of the permanent magnet synchronous motor under dynamic load. By optimizing the motor control strategy, such as maximum torque / ampere control and maximum efficiency control, the energy utilization rate of the motor is improved and energy consumption is reduced.

[0030] In addition, since different algorithms have different advantages and limitations for the control of permanent magnet synchronous motors, the present invention uses improved algorithms for specific scenarios as a basis in the implementation of the control system, monitors the state of the motor from different angles, and uses a serial port for communication in order to cooperate with other systems, as follows:

[0031] 1. Improve control algorithms to suit specific scenarios

[0032] The present invention focuses on the impact of real-world scenario requirements on the operation of a permanent magnet synchronous motor, and improves and optimizes the original control algorithm structure to make it suitable for certain practical scenarios.

[0033] 2. Multi-angle monitoring of motor control system

[0034] In addition to the parameters that need to be measured for normal closed-loop control, monitoring units are set in the motor, control module, drive module, and host computer to measure parameters such as voltage waveform, current, speed, PWM duty cycle, etc., and the parameters are mapped to the control algorithm structure to facilitate system debugging and optimization. At the same time, when a system failure occurs, the fault scope can be quickly narrowed down and the cause of the failure can be accurately found.

[0035] 3. Enrich communication interface information

[0036] Integrate the motor control system, bring out the communication interface to communicate with other devices, enrich the information that the interface can receive as much as possible, and enable the motor system to read more commands to achieve operation in various scenarios.

[0037] 4. Integrated system, interactive and friendly design

[0038] The algorithm function is transplanted into the DSP chip, a dedicated system board is designed, and a matching shell can also be designed and produced. Under the premise of controlling the size to be small and light, it can have friendly human-computer interaction functions through buttons, screens and other devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a block diagram of a permanent magnet synchronous motor control system based on magnetic field orientation involved in the present invention;

[0040] Figure 2 It is a simplified structural diagram of a permanent magnet synchronous motor and a three-phase inverter involved in the present invention;

[0041] Figure 3 It is a simplified model diagram of the motor involved in the present invention;

[0042] Figure 4 is an equivalent circuit diagram of the present invention;

[0043] Figure 5 It is a diagram showing the direction of current involved in the present invention;

[0044] Figure 6 It is a diagram of the direction of magnetic field generated by three-phase connection with different voltages involved in the present invention;

[0045] Figure 7 is a three-phase waveform of the first sector of the present invention;

[0046] Figure 8 This is a three-loop FOC block diagram of the present invention;

[0047] Fig. 9 It is a demonstration of the Clark transformation process involved in the present invention;

[0048] Fig.10 This is a demonstration of the Park transformation process involved in the present invention. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Specific implementation method one:

[0051] A permanent magnet synchronous motor control system based on magnetic field orientation in this embodiment, such as Figure 1 As shown, its components include: power supply module 1, DSP control module 2, motor drive module 3, display drive chip and digital tube 4 and host computer 5, and control object permanent magnet synchronous motor PMSM;

[0052] The DSP control module 2 integrates a FOC control module 6, an IIC module 7, a serial communication module 8, a PWM module 9, an on-chip ADC (labeled 10 in the figure) and an input capture module 11;

[0053] The motor drive module 3 integrates a motor drive chip and a peripheral circuit 12 and a three-phase inverter 13, and the motor drive chip and the peripheral circuit 12 are connected to the three-phase inverter 13;

[0054] The power supply module 1 supplies power to the DSP control module 2 and the motor drive module 3; the FOC control module 6 is connected to the PWM module 9, the on-chip ADC (numbered 10 in the figure) and the input capture module 11; the PWM module 9 is connected to the motor drive chip and the peripheral circuit 12 of the motor drive module 3, the on-chip ADC (numbered 10 in the figure) is connected to the IV conversion circuit 14, and the IV conversion circuit 14 is connected to the three-phase inverter 13; the input capture module 11 is connected to the speed encoder 15, and the speed encoder is connected to the control object PMSM (numbered 16 in the figure); the IIC module 7 is connected to the display driver chip and the digital tube 4; the serial communication module 8 is connected to the host computer 5;

[0055] The DSP control module 2 uses a digital signal processor DSP (Digital Signal Processor) as the main control chip. DSP is a microprocessor specifically used to perform digital signal processing tasks. Compared with general microprocessors (such as CPUs), DSP is optimized for digital signal processing applications and has higher computing performance and stronger real-time processing capabilities. In addition, external peripherals such as buttons, displays, and serial ports are used outside the DSP to monitor and control the operation of the motor.

[0056] Motor driving requires large current and voltage. DSP, like other main control chips, can only generate small voltage and current. A special conversion circuit is needed to convert the small signal output by DSP into a large signal that can drive the motor. At the same time, the parameters of the motor rotation are obtained and sent back to DSP for processing.

[0057] The controlled object (and the motor) is also the measured object. It is connected to the drive circuit and controlled by the DSP. At the same time, the right speed encoder on the motor can obtain the speed and position of the motor and send it to the DSP to form a closed-loop control.

[0058] Figure 1 The control block diagram of the permanent magnet synchronous motor is shown in FIG. 6. The FOC control module 6 embedded in the DSP control module 2 obtains the rotation position, speed and current used by the permanent magnet synchronous motor PMSM of the current control object, and outputs the duty cycle information required by the PWM module 9. The PWM module 9 generates three pairs of PWM waveforms and inputs them into the motor drive circuit to generate corresponding three-phase voltages to control the rotation of the permanent magnet synchronous motor PMSM of the control object. At the same time, the current magnitude of the current driving motor rotation is obtained and input to the on-chip ADC (numbered 10 in the figure) of the DSP control module 2. The orthogonal waveform generated by the current rotation is obtained by the speed encoder and input to the input capture module 11 of the DSP control module 2 to calculate the current speed and position. At the same time, the IIC module 7 is used to control the display driver chip and the digital tube, and the speed information is displayed on the digital tube. The voltage waveform, current waveform and other information used by the DSP control module 2 for rotation are sent to the host computer 5 through the serial communication module for auxiliary debugging.

[0059] We can draw and produce special system boards and shells that meet the needs, so that the system can be miniaturized and commercialized. Under the premise of being able to work offline, we can ensure the stability of the system and improve its ease of use and human-computer interaction friendliness. Specific implementation method 2:

[0061] Different from the first embodiment, the present embodiment is a permanent magnet synchronous motor control system based on magnetic field orientation, the rotation of the permanent magnet synchronous motor relies on the drive of the three-phase inverter 13, and the simplified structure of the three-phase inverter 13 is as follows: Figure 2As shown, the three-phase inverter 13 includes three groups of MOS tubes. In each group of MOS tubes, only one of the upper and lower tubes is turned on and the other is turned off at the same time. In order to ensure that the MOS tube is not burned, the PWM dead time needs to be designed. When the upper tube is turned on, the corresponding phase outputs a high level, and when the lower tube is turned on, the output is a low level. The simplified model of the motor is as follows Figure 3 As shown, each coil is regarded as a winding with the same resistance and connected in the manner shown in the figure, and the direction of the current in the winding is opposite to the direction of the generated magnetic field.

[0062] There are eight situations for the voltage output by the three-phase inverter 13. Assume that the output high level is 1 and the output low level is 0. Take the output mode 100 as an example, that is, phase a outputs a high level, and phases b and c output low levels. The equivalent circuit and current direction are as follows: Figure 4 and Figure 5 As shown:

[0063] When the motor is connected in this way, the three-phase coil generates current, and the current relationship is i a =i b +i c ,i b =i c , the three currents all generate magnetic fields on the corresponding coils. The above content assumes that the current direction is opposite to the magnetic field direction, so the direction of the magnetic field synthesized by the three magnetic fields is horizontal to the right. By analogy, by judging the current size and direction through the three-phase voltage situation, the direction of the magnetic field under different conditions can be obtained, such as Figure 6 The figure shows the direction of the magnetic field generated by three-phase connection with different voltages.

[0064] By three-phase output high and low levels are generated Figure 6The magnetic field shown is called space voltage vector modulation (SVPWM). These six vectors are the basis vectors of SVPWM. When the three-phase output voltage is 000 and 111, there is no current in the winding, and no magnetic field is generated, which is called the zero vector. The range between the two basis vectors is called the sector. When the voltage is output in the form of these six vectors, the rotor of the motor will point to the corresponding direction due to the direction of the magnetic field, but the motor rotation requires the motor to be able to turn in any direction, that is, to be able to generate a magnetic field in any direction, and in order to make the rotational torque variable, the size of the magnetic field is also required to be variable. To generate a magnetic field of any size and direction based on the above six basis vectors, use the two basis vectors of the corresponding sector to synthesize. Taking the first sector as an example, by adjusting the size of the two vectors U4 and U6, a vector of any size and direction in the first sector can be synthesized, and the same is true for the remaining sectors. The size of the basis vector is fixed. If you want to change the size of the basis vector, you can make the basis vector and the zero vector synthesize it. Taking U1 as an example, the voltage output by the three-phase inverter 13 is 100. If you want to add a certain proportion of zero vector (U0 or U7) to it, you can control the size of the U1 direction vector. At the hardware level, the voltage of the U1 vector and the voltage of the zero vector are output in the three-phase inverter in the form of PWM. This will cause the MOS tube to frequently switch between the on and off states. Therefore, a reasonable PWM generation strategy is needed, which can be applied to each sector and ensure that the MOS tube switches at least the number of times in a PWM cycle.

[0065] With the goal of reducing the number of switching times, the principle of distributing the basic vector action sequence can be selected as changing only the switching state of one phase each time the switching state changes, and the zero vector is evenly distributed in time to make the generated PWM symmetrical, thereby effectively reducing the harmonic components of PWM. It can be found that when U1, U2, and U4 are to cooperate with the zero vector to output PWM, selecting U0 can only switch the state of one MOS tube, and U3, U5, and U6 can select U7. At the same time, when the two vectors of each sector are transformed, only one MOS tube has a state switch. Taking the first sector as an example, the switching sequence is switched in the order of U0-U4-U6-U7-U7-U6-U4-U0, and the MOS tube state is only switched once each time. The specific waveform is as follows Figure 7 As shown;

[0066] In sector 1, the voltage varies in each cycle according to Figure 7The output is performed in the manner shown. By controlling the size of T0, T4, T6, and T7, it can be changed according to the specific situation. For example, when T0=T6=T7, the waveform generates the U4 vector. When T0 and T7 change, the size of the vector in the U4 direction also changes. When T4 and T6 are transformed at different proportions in a cycle, the synthesized vector also changes accordingly. Then, by placing T0 and T7 in the waveform at different proportions, the target vector can be realized in the first sector with any size and direction. The specific ratio of these four times still needs specific calculations to be obtained. In DSP development, it is only necessary to write the corresponding data in the ePMW peripheral of the DSP according to the calculated ratio. The waveforms of the remaining sectors are similar to the first sector. It is only necessary to determine which position the current rotor is pointing to and then output PWM according to the strategy of the sector at the current position. Specific implementation method three:

[0068] This embodiment is a permanent magnet synchronous motor control method based on magnetic field orientation. The FOC algorithm is widely used in the control of AC motors such as permanent magnet synchronous motors and induction motors, especially in high-performance drive systems. It provides an efficient and accurate control method, which makes the motor system have better performance and operation stability. Figure 8 The three-loop control block diagram of FOC is finally aimed at outputting torque, i.e., current. The general process is as follows: the three-phase current of the permanent magnet synchronous motor PMSM is collected, and the three-phase current is transformed by Clark and Park to obtain an easy-to-process current signal, which is compared with the set current value and the error is input into the two controllers to obtain the control voltage, and then the voltage for synthesizing the voltage vector is obtained by Park inverse transformation, which is input into the PWM module 9 and the three-phase voltage of the drive motor module is obtained by calculation to complete the control process of the current loop; wherein, the set value of the current is obtained by the speed loop, the encoder on the motor measures the motor speed, which is compared with the set speed, and the error obtained is input into the speed regulator, and the output result is the set value of the current and is sent to the current loop; similarly, the set value of the speed is obtained by the position loop; in this way, a complete three-loop control process is obtained, and the whole process can be adjusted according to the actual situation. For example, when the required speed is too slow, the accuracy of measuring the motor speed is not high, so the speed loop can be abandoned and the current set value can be obtained directly through the position loop. Specific implementation method four:

[0070] Different from the third specific implementation, the present implementation is a permanent magnet synchronous motor control method based on magnetic field orientation. Specifically, the Clark transformation is that the three current directions of the motor differ by 120° and are non-orthogonal. In two-dimensional coordinates, the use of orthogonal vectors can make calculations easier. The new rectangular coordinate system is named α-β coordinates, and the three-phase currents are orthogonalized to α-β coordinates to perform coordinate projection calculations. The process is as follows: Fig. 9 As shown;

[0071] pass Fig. 9 It can be seen that the current in the α-β coordinate is calculated by the following formula:

[0072]

[0073] It should be noted that I α and I β It is a virtual variable. After a set of currents are calculated, it is transformed back through the inverse transformation formula of the above formula and then applied to the three phases of the motor. Specific implementation method five:

[0075] Different from the fourth embodiment, the present embodiment is a method for controlling a permanent magnet synchronous motor based on magnetic field orientation. The Park transformation is as follows: although one-dimensional variables are lost after Clark transformation, the current when the motor rotates is an AC signal, and the current after Clark transformation is also AC. If the two currents under the α-β coordinates can be linearized, the control process can be greatly simplified. This linearization process is Park transformation, and the process is as follows: Fig.10 As shown:

[0076] Like Clark transformation, Park transformation is also a normal coordinate projection process. The angle θ is the angle of rotation of the motor rotor. The transformation formula is:

[0077] I D =cos(θ)I α +sin(θ)I β

[0078] I β = -sin(θ)I α +cos(θ)I β

[0079] The transformed DQ coordinate system rotates with the rotor, and the angle is obtained by the encoder input on the motor. After this transformation, the uniformly rotating vector becomes a constant, and both control variables are linearized, with I D and I Q These two values ​​are the objects of feedback control and are implemented through a linear controller, such as the PID algorithm most commonly used in industry. Specific implementation method six:

[0081] Different from the fifth embodiment, in the present embodiment, a permanent magnet synchronous motor control method based on magnetic field orientation, the process of the FOC control target is as follows: in the above Park transformation, I D and I QIt has a certain physical meaning, because the DQ coordinate system rotates with the rotor and is also an orthogonal coordinate system. This operation can also be regarded as decomposing the rotor flux into variables in the radial and tangential directions of the rotor rotation through decoupling, where I Q is the required current, which represents the output of torque. Therefore, in the three-loop control, the output through the speed loop control is I Q , while I D The setting value I D _ R ef is directly set to zero in the whole control process. The control process of FOC is roughly as described above, and the specific controller algorithm currently used is the PID algorithm.

[0082] The embodiments of the present invention disclose preferred embodiments, but are not limited thereto. A person skilled in the art can easily understand the spirit of the present invention based on the above embodiments and make different extensions and changes. However, as long as they do not deviate from the spirit of the present invention, they are all within the protection scope of the present invention.

Claims

1. A permanent magnet synchronous motor control system based on magnetic field orientation, characterized in that: Its components include: power module, DSP control module, motor drive module, display driver chip, digital tube and host computer; The DSP control module integrates FOC control module, IIC module, serial communication module, PWM module, on-chip ADC and input capture module; The motor drive module integrates a motor drive chip, peripheral circuits and a three-phase inverter, and the motor drive chip and the peripheral circuits are connected to the three-phase inverter; The power module supplies power to the DSP control module and the motor drive module; the FOC control module is connected to the PWM module, the on-chip ADC and the input capture module; the PWM module is connected to the motor drive chip and peripheral circuits of the motor drive module, the on-chip ADC is connected to the IV conversion circuit, and the IV conversion circuit is connected to the three-phase inverter; the input capture module is connected to the speed encoder; the IIC module is connected to the display driver chip and the digital tube; the serial communication module is connected to the host computer; The DSP control module uses a digital signal processor DSP as the main control chip.

2. A permanent magnet synchronous motor control system based on magnetic field orientation according to claim 1, characterized in that: The three-phase inverter comprises three groups of MOS tubes, and only one of the upper and lower tubes of each group of MOS tubes is turned on and the other is turned off at the same time.

3. A method for controlling a permanent magnet synchronous motor based on magnetic field orientation using the system according to any one of the above claims, characterized in that: The three-phase current of the permanent magnet synchronous motor (PMSM) is collected. The three-phase current is transformed by Clark and Park to obtain an easy-to-process current signal. The error is compared with the set current value and input into the two controllers to obtain the control voltage. The voltage used to synthesize the voltage vector is then transformed by Park inverse transformation. The voltage is input into the PWM module and the three-phase voltage of the drive motor module is obtained after calculation, thus completing the control process of the current loop. Among them, the set value of the current is obtained by the speed loop, and the encoder on the motor measures the motor speed, which is compared with the set speed. The error obtained is input into the speed regulator, and the output result is the set value of the current, which is sent to the current loop. Similarly, the set value of the speed is obtained by the position loop, thus obtaining a complete three-loop control process.

4. The method for controlling a permanent magnet synchronous motor based on magnetic field orientation according to claim 3 is characterized in that: The Clark transformation is specifically: The three current directions of the motor differ by 120° and are non-orthogonal. In the two-dimensional coordinate system, the new rectangular coordinate system is named α-β coordinate, and the three-phase current is orthogonalized to α-β coordinate, and the coordinate projection calculation is performed; The current in the α-β coordinate is calculated by the following formula: I α and I β It is a virtual variable. After a set of currents are calculated, it is transformed back through the inverse transformation formula of the above formula and then applied to the three phases of the motor.

5. The method for controlling a permanent magnet synchronous motor based on magnetic field orientation according to claim 4, characterized in that: The Park transformation is specifically: Park transformation is the process of coordinate projection. The angle θ is the angle of rotation of the motor rotor. The transformation formula is: I D =cos(0)I α +sin(0)I β i β =-sin(0)I α +cos(0)I β The transformed DQ coordinate system rotates with the rotor, and the angle is obtained by the encoder input on the motor. After transformation, the uniformly rotating vector becomes a constant value, and both control variables are linearized, with I D and I Q These two values ​​are the objects of feedback control and are implemented through a linear controller.

6. The method for controlling a permanent magnet synchronous motor based on magnetic field orientation according to claim 5, characterized in that: The process of the FOC control target is that in the above Park transformation, the DQ coordinate system follows the rotor rotation to decompose the rotor flux into the radial and tangential directions of the rotor rotation by decoupling, where I Q It is the required current, which represents the output of torque. In the three-loop control, the output through the speed loop control is I Q , I D The setting value I D _ R ef is zero during the entire control process.

Images