Control method of permanent magnet synchronous motor, frequency converter, system and storage medium

Abstract

The invention discloses a permanent magnet synchronous motor control method, a frequency converter, a system and a storage medium. The method comprises the following steps: predicting a next voltage vector angle according to a current voltage vector angle; when the next beat of voltage vector angle passes through the sector center corresponding to the current beat of voltage vector angle, a basic voltage vector is determined according to the sector where the current beat of voltage vector angle is located, and the sector where the current beat of voltage vector angle is located is the same as the sector where the next beat of voltage vector angle is located; determining a compensation voltage vector of the permanent magnet synchronous motor according to the basic voltage vector; and executing a control action of the permanent magnet synchronous motor based on the compensation voltage vector. And the stability and reliability of the permanent magnet synchronous motor control system are improved.

Description

Technical Field

[0001] The present application relates to the field of motor drive technology, and in particular to a control method, a frequency converter, a system and a storage medium for a permanent magnet synchronous motor. Background Art

[0002] Permanent magnet synchronous motors (PMSMs) are increasingly being used in a variety of applications due to their high efficiency, high power density, and high precision. To meet these requirements, PMSM control must address challenges such as wide speed and load ranges, high energy efficiency, and high reliability. This requires PMSMs to have a wider speed control range and load capacity beyond their rated rating.

[0003] In related technologies, overmodulation is often used to increase the DC bus voltage utilization of permanent magnet synchronous motor controllers, thereby achieving a wider speed regulation range and load capacity. When the maximum DC bus voltage utilization is reached, the permanent magnet synchronous motor's speed regulation range and load capacity reach their maximum, and the permanent magnet synchronous motor is now in a six-beat control state.

[0004] However, in the traditional six-beat control scheme, the pulse width modulation (Pulse Width Modulation) control frequency and the motor electrical frequency cannot ensure an integer multiple relationship. As a result, low-frequency harmonics are introduced due to the asymmetry of the three-phase voltage of the permanent magnet synchronous motor, which in turn leads to a decrease in the stability and reliability of the permanent magnet synchronous motor control system. Summary of the Invention

[0005] The embodiments of the present application aim to improve the stability and reliability of a permanent magnet synchronous motor control system by providing a control method, a frequency converter, a system and a storage medium for a permanent magnet synchronous motor.

[0006] An embodiment of the present application provides a control method for a permanent magnet synchronous motor, the control method for a permanent magnet synchronous motor comprising:

[0007] Predict the next beat voltage vector angle based on the current beat voltage vector angle;

[0008] When the next-beat voltage vector angle passes through the center of the sector corresponding to the current-beat voltage vector angle, determining a basic voltage vector according to the sector in which the current-beat voltage vector angle is located, wherein the current-beat voltage vector angle and the next-beat voltage vector angle are located in the same sector;

[0009] Determining a compensation voltage vector of the permanent magnet synchronous motor according to the basic voltage vector;

[0010] A control action of the permanent magnet synchronous motor is performed based on the compensation voltage vector.

[0011] Optionally, before the step of determining the basic voltage vector according to the sector where the current beat voltage vector angle is located when the next beat voltage vector angle passes through the center of the sector corresponding to the current beat voltage vector angle, the method further includes:

[0012] Determining a reference angle according to the sector in which the current beat voltage vector angle is located, wherein different sectors correspond to different reference angles;

[0013] According to the reference angle, the current beat voltage vector angle and the next beat voltage vector angle, it is determined whether the next beat voltage vector angle passes through the center of the sector corresponding to the current beat.

[0014] Optionally, the step of determining whether the voltage vector angle of the next beat passes through the center of the sector corresponding to the current beat according to the reference angle, the current beat voltage vector angle, and the next beat voltage vector angle includes:

[0015] If the current beat voltage vector angle is smaller than the reference angle and the next beat voltage vector angle is larger than the reference angle, determining that the next beat voltage vector angle passes through the sector center;

[0016] Alternatively, if the current beat voltage vector angle is greater than the reference angle and the next beat voltage vector angle is less than the reference angle, it is determined that the next beat voltage vector angle passes through the sector center.

[0017] Optionally, the basic voltage vector includes a first basic voltage vector and a second basic voltage vector, and the step of determining the compensation voltage vector of the permanent magnet synchronous motor according to the basic voltage vector includes:

[0018] Obtaining the current speed frequency of the permanent magnet synchronous motor and the switching frequency of the switch tube;

[0019] Determine a first voltage vector according to the first basic voltage vector, the speed electrical frequency, the switching frequency of the switch tube, and the current beat voltage vector angle;

[0020] Determine a second voltage vector according to the second basic voltage vector, the speed electrical frequency, the switching frequency of the switch tube, and the next-beat voltage vector angle;

[0021] The compensation voltage vector is determined according to the first voltage vector and the second voltage vector.

[0022] Optionally, predicting the next-beat voltage vector angle according to the current-beat voltage vector angle includes:

[0023] Obtaining the current electrical angular velocity of the permanent magnet synchronous motor;

[0024] The next beat voltage vector angle of the permanent magnet synchronous motor is determined according to the electrical angular velocity and the current beat voltage vector angle.

[0025] Optionally, the step of determining the next beat voltage vector angle of the permanent magnet synchronous motor according to the electrical angular velocity and the current beat voltage vector angle includes:

[0026] Determining the electrical frequency of the rotational speed of the permanent magnet synchronous motor according to the electrical angular velocity;

[0027] Determining a first angle according to the rotational speed electrical frequency and the switching frequency of the switch tube;

[0028] A first sum value between the first angle and the current beat voltage vector angle is determined, and the first sum value is used as the next beat voltage vector angle.

[0029] Optionally, the control method of the permanent magnet synchronous motor further includes:

[0030] Get the current DC shaft voltage and AC shaft voltage, as well as the electrical angle of the permanent magnet synchronous motor;

[0031] A current beat voltage vector angle of the permanent magnet synchronous motor is determined according to the DC shaft voltage, the AC shaft voltage, and the electrical angle.

[0032] Optionally, the step of determining a current beat voltage vector angle of the permanent magnet synchronous motor according to the DC shaft voltage, the AC shaft voltage, and the electrical angle includes:

[0033] determining a ratio between the AC shaft voltage and the DC shaft voltage;

[0034] performing an inverse tangent calculation on the ratio to obtain a second angle;

[0035] A second sum value between the second angle and the electrical angle is determined, and the second sum value is used as the current beat voltage vector angle.

[0036] In addition, to achieve the above-mentioned purpose, the present application also provides a frequency converter including: a memory, a processor, and a control program for a permanent magnet synchronous motor stored on the memory and runnable on the processor. When the control program for the permanent magnet synchronous motor is executed by the processor, the steps of the above-mentioned control method for the permanent magnet synchronous motor are implemented.

[0037] In addition, to achieve the above-mentioned purpose, the present application also provides a control system of a permanent magnet synchronous motor, and the control system of the permanent magnet synchronous motor at least includes a frequency converter and a permanent magnet synchronous motor.

[0038] In addition, to achieve the above-mentioned purpose, the present application also provides a computer-readable storage medium on which a control program of a permanent magnet synchronous motor is stored. When the control program of the permanent magnet synchronous motor is executed by a processor, the steps of the above-mentioned control method of the permanent magnet synchronous motor are implemented.

[0039] A technical solution for a control method, inverter, system and storage medium for a permanent magnet synchronous motor provided in the embodiments of the present application adopts a method for predicting the next beat voltage vector angle based on the current beat voltage vector angle. When it is detected that the next beat voltage vector angle crosses the center of the sector corresponding to the current beat, a basic voltage vector is determined according to the sector in which the current beat voltage vector angle is located, and a compensation voltage vector of the permanent magnet synchronous motor is determined according to the basic voltage vector. The technical solution for executing the control action of the permanent magnet synchronous motor based on the compensation voltage vector can perform voltage compensation based on the compensation voltage vector, so that the voltage vector of the next beat is symmetrical with the voltage vector of the current beat, thereby solving the low-frequency harmonics introduced by the asymmetric three-phase voltage of the permanent magnet synchronous motor and improving the stability and reliability of the permanent magnet synchronous motor control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a schematic diagram of the architecture of the control system of the permanent magnet synchronous motor of this application;

[0041] Figure 2 Schematic diagram of sectors for three-phase six-beat control of the permanent magnet synchronous motor of this application;

[0042] Figure 3 This is a flow chart of a first embodiment of a control method for a permanent magnet synchronous motor of the present application;

[0043] Figure 4 This is a detailed flow chart before step S120 of this application;

[0044] Figure 5 This is a detailed flowchart of step S130 of this application;

[0045] Figure 6 This is a detailed flowchart of step S110 of this application;

[0046] Figure 7 This is a flow chart of a fifth embodiment of a control method for a permanent magnet synchronous motor of the present application;

[0047] Figure 8 This is a schematic diagram of the structure of the frequency converter for this application;

[0048] Figure 9 Schematic diagram of the positional relationship between the current beat voltage vector angle and the next beat voltage vector angle.

[0049] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. The above-mentioned drawings are only an embodiment diagram, not the entire invention. DETAILED DESCRIPTION

[0050] To better understand the above technical solutions, exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0051] In related technologies, six-beat control is a special motor control strategy that achieves efficient torque output by precisely controlling the three-phase current of the motor. However, in order to achieve a better control effect, the pulse width modulation control frequency and the motor electrical frequency often need to be selected and adjusted relatively independently to meet the requirements of the control strategy. This also results in them not being able to maintain a strict integer multiple relationship. For example, the pulse width modulation control frequency is a fixed setting, while the motor electrical frequency can be adjusted in real time. This may result in the pulse width modulation control frequency and the motor electrical frequency not being in an integer multiple relationship, thereby introducing low-frequency harmonics due to the asymmetry of the three-phase voltage of the permanent magnet synchronous motor, which in turn leads to a decrease in the stability and reliability of the permanent magnet synchronous motor control system.

[0052] In response to the above problems, this application proposes a control method for a permanent magnet synchronous motor. The main technical solutions include: predicting the next beat voltage vector angle based on the current beat voltage vector angle; when the next beat voltage vector angle crosses the center of the sector corresponding to the current beat voltage vector angle, determining the basic voltage vector based on the sector in which the current beat voltage vector angle is located, wherein the current beat voltage vector angle and the next beat voltage vector angle are in the same sector; determining the compensation voltage vector of the permanent magnet synchronous motor based on the basic voltage vector; and executing the control action of the permanent magnet synchronous motor based on the compensation voltage vector. Since voltage compensation can be performed based on the compensation voltage vector, the voltage vector of the next beat is symmetrical with the voltage vector of the current beat, thereby solving the low-frequency harmonics introduced by the asymmetric three-phase voltage of the permanent magnet synchronous motor and improving the stability and reliability of the permanent magnet synchronous motor control system.

[0053] Before describing the control method of the permanent magnet synchronous motor, the control system of the permanent magnet synchronous motor of the present application is first introduced. Figure 1This is the control system of the permanent magnet synchronous motor of the present application. The control system of the permanent magnet synchronous motor includes a frequency converter and a permanent magnet synchronous motor. The control system of the permanent magnet synchronous motor also includes other modules. The control system of the permanent magnet synchronous motor is a conventional control system in this field. The main improvement of this application is to execute the control method of the permanent magnet synchronous motor of the present application in the frequency converter.

[0054] Optionally, the permanent magnet synchronous motor of the present application may adopt a three-phase six-beat control method. The three-phase six-beat control of the permanent magnet synchronous motor is a basic motor control method used to control the rotor position and speed of the permanent magnet synchronous motor. Figure 2 As shown in the figure, in three-phase six-beat control, each phase of the motor is divided into six equally spaced current states, centered at the vertices of the six hexagons. Specifically, six-beat control drives the motor by varying the phase current. The current in each phase is divided into six different states, which are sequentially applied to the three phases of the motor, generating a rotating magnetic field that drives the motor. In six-beat control, each state persists for a certain period of time before switching to the next state, and so on, forming six equally spaced states. The entire cycle is called a "step," hence the name three-phase six-beat control.

[0055] Specifically, if Figure 3 As shown, in the first embodiment of the present application, the control method of the permanent magnet synchronous motor of the present application includes the following steps:

[0056] Step S110 , predicting the voltage vector angle of the next beat according to the voltage vector angle of the current beat.

[0057] In this embodiment, in a three-phase motor, the current beat and the next beat refer to two consecutive steps in a six-step control cycle. In six-step control, each motor step corresponds to a voltage vector that drives a different phase of the motor. Each step energizes one phase while de-energizing the other two. This allows continuous rotation of the motor through a six-step cycle. Specifically, the current beat refers to the currently executing step, which energizes one phase while de-energizing the other two. For example, if the current beat is the first step, phase A is energized while phases B and C are de-energized. The next beat refers to the step immediately following the current beat, the next step to be executed. The next beat energizes a different phase than the current beat. For example, in the above example, the next beat would be the second step, energizing phase B while phases A and C are de-energized. By repeatedly executing the current beat and the next beat, the motor can rotate continuously at a certain step angle, thereby achieving the desired motion. It should be noted that the current beat and the next beat of a three-phase motor are determined based on a specific control algorithm and sequence; different control algorithms may use different sequences. In specific applications, the order of the current beat and the next beat needs to be determined based on the adopted control strategy and the characteristics of the motor.

[0058] In this embodiment, the voltage vector angle for the next beat depends on the voltage vector angle for the current beat and the control strategy employed. In six-step control, each step excites one phase of the motor, while the other two phases are not excited. Taking the most common three-phase, six-step sinusoidal wave control as an example, the voltage vector angle for the next beat can be calculated as follows: assuming that the phase excited by the current beat is phase A, then the voltage vector angle for the current beat is the phase angle of the voltage of phase A. According to the sequence of six-step control, the phase excited by the next beat is sequentially forward of the phase of the current beat. In other words, the excitation phase for the next beat will be the phase immediately following the excitation phase of the current beat. If the current beat excites phase A, the excitation phase for the next beat will be phase B; if the current beat excites phase B, the excitation phase for the next beat will be phase C; and if the current beat excites phase C, the excitation phase for the next beat will be phase A. Therefore, the voltage vector angle for the next beat can be calculated by determining the excitation phase for the next beat based on the voltage vector angle for the current beat and obtaining the voltage vector angle for that phase.

[0059] Step S120 : When the next-beat voltage vector angle passes through the center of the sector corresponding to the current-beat voltage vector angle, a basic voltage vector is determined according to the sector in which the current-beat voltage vector angle is located, wherein the current-beat voltage vector angle and the next-beat voltage vector angle are located in the same sector.

[0060] In this embodiment, the present application uses one sector as an example. Each sector has a corresponding sector center. In three-phase motor control, determining whether the voltage vector angle in the next cycle will cross the center of the vector sector is necessary to ensure accurate control of the motor's speed and direction of motion. In three-phase motor control, the motor's speed is achieved by changing the position and magnitude of the voltage vector. The position and magnitude of the voltage vector depend on parameters and input signals in the motor control algorithm. Therefore, if the motor control algorithm cannot accurately predict the position and magnitude of the voltage vector, the motor's speed and direction of motion may be affected, resulting in control failure or instability. This can be avoided by determining whether the voltage vector angle in the next cycle will cross the center of the vector sector. If the voltage vector angle in the next cycle will cross the center of the vector sector, the control algorithm can take appropriate measures to adjust the motor's speed and direction of motion to ensure control accuracy and stability. For example, the magnitude and position of the voltage vector can be changed, or the parameters of the control algorithm can be adjusted to suit the current motor state and the desired control objectives. Therefore, in three-phase motor control, determining whether the voltage vector angle in the next cycle will cross the center of the vector sector is a critical step in ensuring accurate, stable, and reliable motor control.

[0061] In this embodiment, the sector in which the current beat voltage vector angle is located is the same as the sector in which the next beat voltage vector angle is located, and the sector center is the sector center of the sector in which the current beat voltage vector angle and the next beat voltage vector angle are located. Each sector has a corresponding base voltage vector, which refers to a reference voltage vector used to represent the voltage magnitude and phase in a three-phase AC circuit. Typically, the magnitude of the base voltage vector is defined as the effective value of the grid voltage, and the phase angle is 0 degrees or an arbitrary fixed value. In motor control systems, for ease of calculation and control, voltage and current are typically represented as vectors, that is, complex numbers consisting of magnitude and phase angle. In this case, the base voltage vector can be used as a reference system to describe the relative magnitudes and phase differences of other voltage vectors. For example, in a space vector modulation control system, the motor controller can calculate and control the magnitude and phase of each voltage vector based on the base voltage vector to achieve precise control of the motor speed and direction.

[0062] Step S130: determining a compensation voltage vector of the permanent magnet synchronous motor according to the basic voltage vector.

[0063] Step S140 : executing a control action of the permanent magnet synchronous motor based on the compensation voltage vector.

[0064] In this embodiment, there are two basic voltage vectors in each sector, namely the first basic voltage vector and the second basic voltage vector. Based on the first basic voltage vector and the second basic voltage vector, the compensation voltage vector calculation formula of the present application can be used to calculate the compensation voltage vector of the permanent magnet synchronous motor, and voltage compensation is performed based on the compensation voltage vector, so that the voltage vector of the next beat is symmetrical with the voltage vector of the current beat, thereby solving the low-frequency harmonics introduced by the asymmetric three-phase voltage of the permanent magnet synchronous motor and improving the stability and reliability of the permanent magnet synchronous motor control system.

[0065] In this embodiment, in the six-beat control of the motor, compensation between the current beat and the next beat is performed in order to maintain the stability and accuracy of the motor operation. Compensation refers to fine-tuning or correcting the control signal of the motor between the current beat and the next beat. This is because in actual applications, due to the influence of various factors (such as load changes, power supply fluctuations, sensor errors, etc.), the speed or position of the motor may slightly cross the expected target value. By compensating between the current beat and the next beat, the control signal can be adjusted according to the actual situation to correct the deviation of the motor and keep it running on the expected trajectory. This can improve the stability and accuracy of the motor system and ensure that the required speed, position or other control parameters are accurately achieved.

[0066] According to the above technical solution, this embodiment adopts a technical solution of predicting the voltage vector angle of the next beat based on the voltage vector angle of the current beat. When it is detected that the voltage vector angle of the next beat crosses the center of the sector corresponding to the current beat, the basic voltage vector is determined according to the sector in which the voltage vector angle of the current beat is located, and the compensation voltage vector of the permanent magnet synchronous motor is determined based on the basic voltage vector. The control action of the permanent magnet synchronous motor is executed based on the compensation voltage vector. Since voltage compensation can be performed based on the compensation voltage vector, the voltage vector of the next beat is symmetrical with the voltage vector of the current beat, thereby solving the low-frequency harmonics introduced by the asymmetric three-phase voltage of the permanent magnet synchronous motor and improving the stability and reliability of the permanent magnet synchronous motor control system.

[0067] Further, based on the first embodiment, in the second embodiment of the present application, referring to Figure 4 Before step S120, the following steps are also included:

[0068] Step S210 : determining a reference angle according to the sector where the current beat voltage vector angle is located, wherein different sectors correspond to different reference angles.

[0069] In this embodiment, the reference angle can be determined according to the formula π / 6+n*π / 3, where n represents the serial number corresponding to the sector, n is greater than or equal to 0 and less than 6, and the reference angles corresponding to different sectors are different. For example, there are the following situations:

[0070] When n is equal to 0, it is located in sector 0, and the corresponding reference angle is 30°.

[0071] When n is equal to 1, it is located in sector 1, and the corresponding reference angle is 90°.

[0072] When n is equal to 2, it is located in sector 2, and the corresponding reference angle is 150°.

[0073] When n is equal to 3, it is located in sector 3, and the corresponding reference angle is 210°.

[0074] When n is equal to 4, it is located in sector 4, and the corresponding reference angle is 270°.

[0075] When n is equal to 5, it is located in sector 5, and the corresponding reference angle is 330°.

[0076] Step S220 , determining whether the voltage vector angle of the next beat passes through the center of the sector corresponding to the current beat according to the reference angle, the current beat voltage vector angle, and the next beat voltage vector angle.

[0077] Optionally, if the current beat voltage vector angle is less than the reference angle and the next beat voltage vector angle is greater than the reference angle, it is determined that the next beat voltage vector angle crosses the center of the sector. If the current beat voltage vector angle is greater than the reference angle and the next beat voltage vector angle is less than the reference angle, it is determined that the next beat voltage vector angle crosses the center of the sector. There are the following situations:

[0078] When n is 0, it is located in sector 0, and the corresponding reference angle is 30°. If the current beat voltage vector angle is less than 30° and the next beat voltage vector angle is greater than 30°, it is determined that the next beat voltage vector angle passes through the center of the sector; or if the current beat voltage vector angle is greater than 30° and the next beat voltage vector angle is less than 30°, it is determined that the next beat voltage vector angle passes through the center of the sector.

[0079] When n is 1, it is located in sector 1, and the corresponding reference angle is 90°. If the current beat voltage vector angle is less than 90° and the next beat voltage vector angle is greater than 90°, it is determined that the next beat voltage vector angle passes through the center of the sector; or if the current beat voltage vector angle is greater than 90° and the next beat voltage vector angle is less than 90°, it is determined that the next beat voltage vector angle passes through the center of the sector.

[0080] When n is 2, it is located in sector 2, and the corresponding reference angle is 150°. If the current beat voltage vector angle is less than 150° and the next beat voltage vector angle is greater than 150°, it is determined that the next beat voltage vector angle passes through the center of the sector; or if the current beat voltage vector angle is greater than 150° and the next beat voltage vector angle is less than 150°, it is determined that the next beat voltage vector angle passes through the center of the sector.

[0081] When n is 3, it is located in sector 3, and the corresponding reference angle is 210°. If the current beat voltage vector angle is less than 210° and the next beat voltage vector angle is greater than 210°, it is determined that the next beat voltage vector angle passes through the center of the sector; or if the current beat voltage vector angle is greater than 210° and the next beat voltage vector angle is less than 210°, it is determined that the next beat voltage vector angle passes through the center of the sector.

[0082] When n is 4, it is located in sector 4, and the corresponding reference angle is 270°. If the current beat voltage vector angle is less than 270° and the next beat voltage vector angle is greater than 270°, it is determined that the next beat voltage vector angle passes through the center of the sector; or if the current beat voltage vector angle is greater than 270° and the next beat voltage vector angle is less than 270°, it is determined that the next beat voltage vector angle passes through the center of the sector.

[0083] When n is 5, it is located in sector 5, and the corresponding reference angle is 330°. If the current beat voltage vector angle is less than 330° and the next beat voltage vector angle is greater than 330°, it is determined that the next beat voltage vector angle passes through the center of the sector; alternatively, if the current beat voltage vector angle is greater than 330° and the next beat voltage vector angle is less than 330°, it is determined that the next beat voltage vector angle passes through the center of the sector.

[0084] According to the above technical solution, this embodiment adopts a technical means of determining whether the voltage vector angle of the next beat crosses the center of the sector corresponding to the current beat based on the reference angle, the current beat voltage vector angle and the next beat voltage vector angle, and judges whether the voltage vector angle of the next beat will cross the center of the vector sector, thereby ensuring that the speed and movement direction of the motor can be accurately controlled.

[0085] In other embodiments, whether the voltage vector angle of the next beat passes through the center of the sector corresponding to the current beat may be determined according to the following method:

[0086] Optionally, the voltage vector with the smallest angle in the current sector is selected as the reference vector, and then the angle between the next voltage vector and the reference vector is calculated. If the next voltage vector angle is within the current sector and far from the reference vector, the next voltage vector angle will not cross the center of the vector sector.

[0087] Optionally, for each voltage vector, calculate its projected length at the center of the voltage vector sector. Then, sum the projected lengths of all voltage vectors to obtain the total projected length at the center of the sector. If the projected length of the next voltage vector is less than half of the total projected length, the next voltage vector will not cross the center of the vector sector.

[0088] Further, based on the first embodiment, in the third embodiment of the present application, referring to Figure 5 In step S130, determining the compensation voltage vector of the permanent magnet synchronous motor according to the basic voltage vector includes:

[0089] Step S131, obtaining the current speed frequency of the permanent magnet synchronous motor and the switching frequency of the switch tube.

[0090] In this embodiment, the permanent magnet synchronous motor's speed frequency, also known as the power supply frequency, is linearly related to the motor's speed: that is, speed frequency = (speed * number of pole pairs in the motor's rotating magnetic field) / 60. The speed frequency can be adjusted in real time. The motor's speed can be measured using an encoder or Hall effect sensor mounted on the motor's output shaft, which can then be used to calculate the motor's current speed frequency.

[0091] In this embodiment, the switching frequency of the switch tube refers to the number of times the switch tube switches per second, usually expressed in Hertz (Hz). In permanent magnet synchronous motor control, the switching frequency of the switch tube is fixed. Fixed switching frequency helps to maintain the stability of the system. By fixing the switching frequency, the dynamic changes in the motor control system can be reduced, the calculation complexity of the controller can be reduced, and the response speed and stability of the control system can be improved. In addition, the fixed setting of the switching frequency can effectively reduce current harmonics. In SVPWM control, the switching operation of the switch tube will introduce some high-order harmonic components, which may have adverse effects on the motor and the power system. By fixing the switching frequency, the frequency and amplitude of these harmonic components can be controlled, thereby reducing the impact of current harmonics.

[0092] Step S132: determining a first voltage vector according to the first basic voltage vector, the speed electrical frequency, the switching frequency of the switch tube, and the current beat voltage vector angle.

[0093] Step S133: determining a second voltage vector according to the second basic voltage vector, the speed electrical frequency, the switching frequency of the switch tube, and the next-beat voltage vector angle.

[0094] Step S134: determining the compensation voltage vector according to the first voltage vector and the second voltage vector.

[0095] Optionally, the compensation voltage vector may be calculated using a compensation voltage vector calculation formula, which is:

[0096]

[0097] Among them, V s_pre is the compensation voltage vector, n is the sector where the current beat voltage vector angle is located, V1 is the first basic voltage vector; V2 is the second basic voltage vector, f Motor f is the electrical frequency of the motor speed; PWM is the switching frequency of the switch tube; θ1 is the current beat voltage vector angle, and θ2 is the next beat voltage vector angle; is the first voltage vector; is the second voltage vector.

[0098] According to the above technical solution, this embodiment adjusts the control signal based on actual conditions by performing compensation between the current beat and the next beat, correcting motor deviations and keeping the motor running on the desired trajectory. This improves the stability and accuracy of the motor system, ensuring that the desired speed, position, or other control parameters are accurately achieved.

[0099] Further, based on the first embodiment, in the fourth embodiment of the present application, referring to Figure 6 , step S110 includes:

[0100] Step S111, obtaining the current electrical angular velocity of the permanent magnet synchronous motor.

[0101] In this embodiment, electrical angular velocity represents the speed of the motor rotor in the electrical coordinate system, measured in radians per second (rad / s). It refers to the speed of the motor's magnetic field and is related to the motor's voltage frequency and pole pair number. Electrical angular velocity is typically estimated or controlled by measuring the motor's winding current and can be used to control the motor's speed and position.

[0102] Alternatively, the electrical angular velocity may be acquired through a position sensor or a position observer.

[0103] Optionally, the three-phase current output by the permanent magnet synchronous motor can be transformed to obtain the current component on the d-axis and the current component on the q-axis in the two-phase rotating coordinate system; the line voltage output by the permanent magnet synchronous motor can be transformed to obtain the voltage component on the d-axis in the two-phase rotating coordinate system; based on the current component on the d-axis, the current component on the q-axis, and the voltage component on the d-axis, the back electromotive force component of the permanent magnet synchronous motor on the d-axis in the two-phase rotating coordinate system is determined, and the specific frequency-doubling component in the back electromotive force component on the d-axis is filtered out; the difference between the target value of the back electromotive force component on the d-axis and the back electromotive force component on the d-axis from which the specific frequency-doubling component is filtered out is input into a PI regulator, and the output of the PI regulator is used as the current electrical angular velocity of the permanent magnet synchronous motor.

[0104] Step S112: determining a next beat voltage vector angle of the permanent magnet synchronous motor according to the electrical angular velocity and the current beat voltage vector angle.

[0105] Optionally, the electrical frequency of the permanent magnet synchronous motor's rotational speed can be determined based on the electrical angular velocity. A first angle can be determined based on the electrical frequency of the rotational speed and the switching frequency of the switch tube. A first sum of the first angle and the current beat voltage vector angle is determined, and the first sum is used as the next beat voltage vector angle.

[0106] Alternatively, the formula Calculate the voltage vector angle of the next beat, where f Motor f is the electrical frequency of the motor speed; PWM is the switching frequency of the switch tube; θ1 is the current beat voltage vector angle, and θ2 is the next beat voltage vector angle. Figure 9 , Figure 9 Schematic diagram of the positional relationship between θ1 and θ2 in the same sector.

[0107] Optionally, when the PWM comparison value adopts single update, i.e., valley or peak update, according to the formula Calculate the voltage vector angle of the next beat; when the PWM comparison value adopts double update, that is, both the trough and the peak are updated, according to the formula The voltage vector angle of the next beat is calculated.

[0108] According to the above technical solution, this embodiment adopts a technical means to determine the next beat voltage vector angle of the permanent magnet synchronous motor based on the electrical angular velocity and the current beat voltage vector angle. The next beat voltage vector angle is obtained by calculation, providing a basis for whether to perform voltage vector compensation subsequently.

[0109] Further, based on the first embodiment, in the fifth embodiment of the present application, referring to Figure 7 , the control method of the permanent magnet synchronous motor of the present application also includes:

[0110] Step S310: Acquire the current DC shaft voltage and AC shaft voltage, and the electrical angle of the permanent magnet synchronous motor.

[0111] In this embodiment, the electrical angle represents the position of the motor rotor in the electrical coordinate system. The electrical angle refers to the electrical angle that the motor rotor passes through during one electrical cycle and is usually expressed in radians. It is an angle relative to a reference point or starting position. The change in the electrical angle is related to the rotation of the motor and can be used to determine the position and direction of the motor rotor. The electrical angle is usually measured by an encoder or sensor and is used to monitor the rotor position of the motor in real time and implement closed-loop control. The electrical angle is one of the important parameters in permanent magnet motor control, and its size is related to the speed and torque of the permanent magnet motor. In permanent magnet motor control, it is usually necessary to measure and control the electrical angle of the rotor to achieve precise torque control and appropriate commutation control.

[0112] Step S320 , determining a current beat voltage vector angle of the permanent magnet synchronous motor according to the DC shaft voltage, the AC shaft voltage, and the electrical angle.

[0113] Optionally, a ratio between the AC shaft voltage and the DC shaft voltage is determined, an arc tangent is calculated on the ratio to obtain a second angle, a second sum between the second angle and the electrical angle is determined, and the second sum is used as the current beat voltage vector angle.

[0114] According to the above technical solution, this embodiment adopts a technical means to determine the current beat voltage vector angle of the permanent magnet synchronous motor based on the DC shaft voltage, the AC shaft voltage and the electrical angle. The current beat voltage vector angle is obtained by calculation, providing a basis for whether to perform voltage vector compensation subsequently.

[0115] The embodiments of the present application provide embodiments of a control method for a permanent magnet synchronous motor. It should be noted that although a logical order is shown in the flow chart, in some cases, the steps shown or described may be performed in an order different from that shown here.

[0116] like Figure 8 As shown, Figure 8 This is a structural diagram of the hardware operating environment of the frequency converter involved in the embodiment of the present application. The frequency converter may include: a processor 1001, such as a CPU, a memory 1005, a user interface 1003, a network interface 1004, and a communication bus 1002. Among them, the communication bus 1002 is used to realize the connection and communication between these components. The user interface 1003 may include a display screen, an input unit such as a keyboard, and the user interface 1003 may optionally include a standard wired interface and a wireless interface. The network interface 1004 may optionally include a standard wired interface and a wireless interface (such as a WI-FI interface). The memory 1005 may be a high-speed RAM memory, or a stable memory, such as a disk memory. The memory 1005 may optionally be a storage device independent of the aforementioned processor 1001.

[0117] Those skilled in the art will understand that Figure 8 The inverter structure shown in the figure does not constitute a limitation to the inverter, and may include more or fewer components than shown in the figure, or combine certain components, or arrange the components differently.

[0118] like Figure 8 As shown, the memory 1005 as a storage medium may include an operating system, a network communication module, a user interface module, and a control program for the permanent magnet synchronous motor. The operating system is a program that manages and controls the hardware and software resources of the inverter, the control program for the permanent magnet synchronous motor, and the operation of other software or programs.

[0119] exist Figure 8 In the inverter shown, the user interface 1003 is mainly used to connect to the terminal and communicate data with the terminal; the network interface 1004 is mainly used for the background server and communicates data with the background server; the processor 1001 can be used to call the control program of the permanent magnet synchronous motor stored in the memory 1005.

[0120] In this embodiment, the frequency converter includes: a memory 1005, a processor 1001, and a control program for a permanent magnet synchronous motor stored in the memory and executable on the processor, wherein:

[0121] When the processor 1001 calls the control program of the permanent magnet synchronous motor stored in the memory 1005, it performs the following operations:

[0122] Predict the next beat voltage vector angle based on the current beat voltage vector angle;

[0123] When the next-beat voltage vector angle passes through the center of the sector corresponding to the current-beat voltage vector angle, determining a basic voltage vector according to the sector in which the current-beat voltage vector angle is located, wherein the current-beat voltage vector angle and the next-beat voltage vector angle are located in the same sector;

[0124] Determining a compensation voltage vector of the permanent magnet synchronous motor according to the basic voltage vector;

[0125] A control action of the permanent magnet synchronous motor is performed based on the compensation voltage vector.

[0126] When the processor 1001 calls the control program of the permanent magnet synchronous motor stored in the memory 1005, it performs the following operations:

[0127] Determining a reference angle according to the sector in which the current beat voltage vector angle is located, wherein different sectors correspond to different reference angles;

[0128] According to the reference angle, the current beat voltage vector angle and the next beat voltage vector angle, it is determined whether the next beat voltage vector angle passes through the center of the sector corresponding to the current beat.

[0129] When the processor 1001 calls the control program of the permanent magnet synchronous motor stored in the memory 1005, it performs the following operations:

[0130] If the current beat voltage vector angle is smaller than the reference angle and the next beat voltage vector angle is larger than the reference angle, determining that the next beat voltage vector angle passes through the sector center;

[0131] Alternatively, if the current beat voltage vector angle is greater than the reference angle and the next beat voltage vector angle is less than the reference angle, it is determined that the next beat voltage vector angle passes through the sector center.

[0132] When the processor 1001 calls the control program of the permanent magnet synchronous motor stored in the memory 1005, it performs the following operations:

[0133] Obtaining the current speed frequency of the permanent magnet synchronous motor and the switching frequency of the switch tube;

[0134] Determine a first voltage vector according to the first basic voltage vector, the speed electrical frequency, the switching frequency of the switch tube, and the current beat voltage vector angle;

[0135] Determine a second voltage vector according to the second basic voltage vector, the speed electrical frequency, the switching frequency of the switch tube, and the next-beat voltage vector angle;

[0136] The compensation voltage vector is determined according to the first voltage vector and the second voltage vector.

[0137] When the processor 1001 calls the control program of the permanent magnet synchronous motor stored in the memory 1005, it performs the following operations:

[0138] Obtaining the current electrical angular velocity of the permanent magnet synchronous motor;

[0139] The next beat voltage vector angle of the permanent magnet synchronous motor is determined according to the electrical angular velocity and the current beat voltage vector angle.

[0140] When the processor 1001 calls the control program of the permanent magnet synchronous motor stored in the memory 1005, it performs the following operations:

[0141] Determining the electrical frequency of the rotational speed of the permanent magnet synchronous motor according to the electrical angular velocity;

[0142] Determining a first angle according to the rotational speed electrical frequency and the switching frequency of the switch tube;

[0143] A first sum value between the first angle and the current beat voltage vector angle is determined, and the first sum value is used as the next beat voltage vector angle.

[0144] When the processor 1001 calls the control program of the permanent magnet synchronous motor stored in the memory 1005, it performs the following operations:

[0145] Get the current DC shaft voltage and AC shaft voltage, as well as the electrical angle of the permanent magnet synchronous motor;

[0146] A current beat voltage vector angle of the permanent magnet synchronous motor is determined according to the DC shaft voltage, the AC shaft voltage, and the electrical angle.

[0147] When the processor 1001 calls the control program of the permanent magnet synchronous motor stored in the memory 1005, it performs the following operations:

[0148] determining a ratio between the AC shaft voltage and the DC shaft voltage;

[0149] performing an inverse tangent calculation on the ratio to obtain a second angle;

[0150] A second sum value between the second angle and the electrical angle is determined, and the second sum value is used as the current beat voltage vector angle.

[0151] Based on the same inventive concept, an embodiment of the present application also provides a computer-readable storage medium, which stores a control program for a permanent magnet synchronous motor. When the control program for the permanent magnet synchronous motor is executed by a processor, it implements the various steps of the control method for the permanent magnet synchronous motor as described above and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0152] Since the storage medium provided in the embodiments of this application is the storage medium used to implement the method of the embodiments of this application, those skilled in the art will be able to understand the specific structure and variations of the storage medium based on the method described in the embodiments of this application, and therefore will not be described in detail here. All storage media used in the method of the embodiments of this application fall within the scope of protection to be provided by this application.

[0153] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or system comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or system. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or system comprising the element.

[0154] The serial numbers of the above embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0155] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus the necessary general hardware platform, and of course can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes a number of instructions for enabling a terminal device (which can be a mobile phone, computer, server, TV, or network device, etc.) to execute the methods described in each embodiment of the present application.

[0156] The above are only preferred embodiments of the present application and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A control method for a permanent magnet synchronous motor, characterized in that: The control method of the permanent magnet synchronous motor includes: Predict the next beat voltage vector angle based on the current beat voltage vector angle; When the next-beat voltage vector angle passes through the center of the sector corresponding to the current-beat voltage vector angle, determining a basic voltage vector according to the sector in which the current-beat voltage vector angle is located, wherein the current-beat voltage vector angle and the next-beat voltage vector angle are located in the same sector; Determining a compensation voltage vector of the permanent magnet synchronous motor according to the basic voltage vector; A control action of the permanent magnet synchronous motor is performed based on the compensation voltage vector.

2. The control method of the permanent magnet synchronous motor according to claim 1, characterized in that: Before the step of determining the basic voltage vector according to the sector where the current beat voltage vector angle is located when the next beat voltage vector angle passes through the center of the sector corresponding to the current beat voltage vector angle, the method further includes: Determining a reference angle according to the sector in which the current beat voltage vector angle is located, wherein different sectors correspond to different reference angles; According to the reference angle, the current beat voltage vector angle and the next beat voltage vector angle, it is determined whether the next beat voltage vector angle passes through the center of the sector corresponding to the current beat.

3. The control method of the permanent magnet synchronous motor according to claim 2, characterized in that: The step of determining whether the voltage vector angle of the next beat passes through the center of the sector corresponding to the current beat according to the reference angle, the current beat voltage vector angle, and the next beat voltage vector angle includes: If the current beat voltage vector angle is smaller than the reference angle and the next beat voltage vector angle is larger than the reference angle, determining that the next beat voltage vector angle passes through the sector center; Alternatively, if the current beat voltage vector angle is greater than the reference angle and the next beat voltage vector angle is less than the reference angle, it is determined that the next beat voltage vector angle passes through the sector center.

4. The control method of the permanent magnet synchronous motor according to claim 1, wherein: The basic voltage vector includes a first basic voltage vector and a second basic voltage vector, and the step of determining the compensation voltage vector of the permanent magnet synchronous motor according to the basic voltage vector includes: Obtaining the current speed frequency of the permanent magnet synchronous motor and the switching frequency of the switch tube; Determine a first voltage vector according to the first basic voltage vector, the speed electrical frequency, the switching frequency of the switch tube, and the current beat voltage vector angle; Determine a second voltage vector according to the second basic voltage vector, the speed electrical frequency, the switching frequency of the switch tube, and the next-beat voltage vector angle; The compensation voltage vector is determined according to the first voltage vector and the second voltage vector.

5. The control method of the permanent magnet synchronous motor according to claim 1, wherein: The predicting of the next beat voltage vector angle according to the current beat voltage vector angle includes: Obtaining the current electrical angular velocity of the permanent magnet synchronous motor; The next beat voltage vector angle of the permanent magnet synchronous motor is determined according to the electrical angular velocity and the current beat voltage vector angle.

6. The control method of the permanent magnet synchronous motor according to claim 5, characterized in that: The step of determining the next beat voltage vector angle of the permanent magnet synchronous motor according to the electrical angular velocity and the current beat voltage vector angle includes: Determining the electrical frequency of the rotational speed of the permanent magnet synchronous motor according to the electrical angular velocity; Determining a first angle according to the rotational speed electrical frequency and the switching frequency of the switch tube; A first sum value between the first angle and the current beat voltage vector angle is determined, and the first sum value is used as the next beat voltage vector angle.

7. The control method of a permanent magnet synchronous motor according to claim 1, wherein: The control method of the permanent magnet synchronous motor further includes: Get the current DC shaft voltage and AC shaft voltage, as well as the electrical angle of the permanent magnet synchronous motor; A current beat voltage vector angle of the permanent magnet synchronous motor is determined according to the DC shaft voltage, the AC shaft voltage, and the electrical angle.

8. The control method of the permanent magnet synchronous motor according to claim 7, characterized in that: The step of determining the current beat voltage vector angle of the permanent magnet synchronous motor according to the DC shaft voltage, the AC shaft voltage and the electrical angle comprises: determining a ratio between the AC shaft voltage and the DC shaft voltage; performing an inverse tangent calculation on the ratio to obtain a second angle; A second sum value between the second angle and the electrical angle is determined, and the second sum value is used as the current beat voltage vector angle.

9. A frequency converter, characterized in that: The frequency converter includes: a memory, a processor, and a control program of the permanent magnet synchronous motor stored in the memory and running on the processor. When the control program of the permanent magnet synchronous motor is executed by the processor, the steps of the control method of the permanent magnet synchronous motor according to any one of claims 1 to 8 are implemented.

10. A control system for a permanent magnet synchronous motor, characterized in that: The control system of the permanent magnet synchronous motor includes at least the frequency converter and the permanent magnet synchronous motor according to claim 9.

11. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a control program of the permanent magnet synchronous motor, and when the control program of the permanent magnet synchronous motor is executed by the processor, the steps of the control method of the permanent magnet synchronous motor according to any one of claims 1 to 8 are implemented.

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