Motor and control method, device, controller, storage medium and program product thereof

Abstract

The application belongs to the technical field of electric machines, and discloses an electric machine and a control method, device, controller, storage medium and computer program product thereof, the method comprising: before starting the electric machine, injecting a preset voltage signal to the d-axis voltage of the speed loop; obtaining the initial position of the rotor in the electric machine; based on the initial position of the rotor in the electric machine, setting the d-axis target current of the current loop, setting the target speed of the electric machine, and setting the position observation algorithm of the speed loop, controlling the zero-speed closed-loop starting and running of the electric machine; obtaining the speed of the electric machine; according to the speed of the electric machine, switching the d-axis target current of the current loop and the position observation algorithm of the speed loop, and continuing to control the closed-loop running of the electric machine. According to the scheme, the zero-speed closed-loop starting of the electric machine is controlled when the electric machine starts, and the observation algorithm is smoothly switched during the process of the electric machine from static to speed-up, so that mechanical reverse rotation caused when the electric machine starts is avoided, and the reliability of the electric machine is improved.

Description

Technical Field

[0001] This invention belongs to the field of motor technology, specifically relating to a motor control method, device, motor controller, motor, storage medium, and computer program product, and particularly to a sensorless zero-speed closed-loop start and full-speed-range control method, device, motor controller, motor, storage medium, and computer program product for a motor (such as a permanent magnet synchronous motor). Background Technology

[0002] Electric motors (such as permanent magnet synchronous motors, PMSMs) have become the mainstream choice for modern drive systems due to their advantages such as high power density, high efficiency, and large starting torque. However, high-performance motor control systems have extremely stringent requirements for the accuracy of motor speed and rotor position angle. While mechanical sensors can provide reliable signals, they also introduce bottlenecks such as space occupation, increased cost, reduced reliability, and limited application. Sensorless control methods estimate speed and position through electrical signals, effectively avoiding hardware dependence and significantly improving the reliability of motor control systems while reducing costs. However, in related solutions, sensorless control methods in motor control systems are prone to mechanical reversal during motor startup, affecting motor reliability.

[0003] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Summary of the Invention

[0004] The purpose of this invention is to provide a motor control method, device, motor controller, motor, storage medium, and computer program product to solve the problem that sensorless control methods in motor (such as permanent magnet synchronous motor) control systems in related solutions are prone to mechanical reversal during motor startup, affecting motor reliability. This invention achieves efficient sensorless control of the entire motor speed range by controlling the motor to start at zero speed in a closed-loop manner and smoothly switching the observation algorithm during the motor's acceleration from standstill. This avoids mechanical reversal during motor startup and improves motor reliability. The motor controller relates to the manufacture of power electronic components.

[0005] This invention provides a motor control method, wherein the motor control system has a current loop and a speed loop; the motor control method includes: injecting a preset voltage signal into the d-axis voltage of the speed loop before the motor starts; obtaining the initial position of the rotor in the motor; based on the initial position of the rotor in the motor, setting the d-axis target current of the current loop, setting the target speed of the motor, and setting the position observation algorithm of the speed loop, controlling the motor to start and run in a zero-speed closed loop; obtaining the speed of the motor; and according to the speed of the motor, switching the d-axis target current of the current loop and switching the position observation algorithm of the speed loop, continuing to control the closed-loop operation of the motor.

[0006] In some implementations, a preset voltage signal is included, including: a square wave voltage signal V. inj Injecting a preset voltage signal into the d-axis voltage of the speed loop includes: injecting a square wave voltage signal V into the d-axis voltage of the speed loop when the motor is stationary. inj This is to generate the three-phase current of the motor at the three-phase windings of the motor.

[0007] In some embodiments, obtaining the initial position of the rotor in the motor includes: obtaining the three-phase current of the motor based on a preset voltage signal injected into the d-axis voltage of the speed loop; and determining the rotational speed and angle of the rotor in the motor through the current loop based on the three-phase current of the motor, as the initial position of the rotor in the motor.

[0008] In some embodiments, the position observation algorithm of the speed loop includes: a preset first observation algorithm; based on the initial position of the rotor in the motor, setting the d-axis target current of the current loop, setting the target speed of the motor, and setting the position observation algorithm of the speed loop to control the motor to start and run at zero speed, including: setting the d-axis target current of the current loop to a positive value, setting the target speed of the motor in the speed loop, and setting the position observation algorithm of the speed loop to observe using the preset first observation algorithm; based on the initial position of the rotor in the motor, controlling the motor to start at zero speed in the closed loop when the speed of the motor is zero.

[0009] In some implementations, setting the d-axis target current of the current loop to a positive value includes: setting the d-axis target current i of the current loop. dref A starting current i is given to the d-axis of the motor. dstart And the starting current i of the d-axis of the motor dstart >0.

[0010] In some implementations, setting the d-axis target current of the current loop to a positive value further includes: calculating the d-axis starting current i of the motor using the following formula.dstart : where i dstart =k1*i rated k1 is a preset calculation coefficient, and 0 < k1 < 1; i rated The rated current of the motor is given.

[0011] In some implementations, the target d-axis current of the current loop is switched and the position observation algorithm of the speed loop is switched according to the speed of the motor, and the closed-loop operation of the motor is continued to be controlled. This includes: determining whether the speed of the motor is greater than or equal to a preset first speed threshold; if it is determined that the speed of the motor is greater than or equal to the preset speed threshold, then the target d-axis current of the current loop is switched and the position observation algorithm of the speed loop is switched, and the closed-loop operation of the motor is continued to be controlled.

[0012] In some implementations, switching the d-axis target current of the current loop and switching the position observation algorithm of the speed loop to continue controlling the closed-loop operation of the motor includes: switching the d-axis target current of the current loop from a positive value to a zero value, and smoothly switching the position observation algorithm of the speed loop from a preset first observation algorithm to a preset second observation algorithm to continue controlling the closed-loop operation of the motor.

[0013] In some embodiments, the position observation algorithm of the speed loop includes: a preset first observation algorithm and a preset second observation algorithm; smoothly switching the position observation algorithm of the speed loop from the preset first observation algorithm to the preset second observation algorithm includes: determining whether the speed of the motor is less than a preset second speed threshold; wherein the preset second speed threshold is greater than the preset first speed threshold; if it is determined that the speed of the motor is less than the preset second speed threshold, then the preset first observation algorithm and the preset second observation algorithm are weighted and fused to obtain a fused observation algorithm, which is used as the position observation algorithm of the speed loop; if it is determined that the speed of the motor is greater than or equal to the preset second speed threshold, then the preset second observation algorithm is used as the position observation algorithm of the speed loop.

[0014] In some implementations, a weighted fusion of a preset first observation algorithm and a preset second observation algorithm is performed to obtain a fused observation algorithm, including: weighted fusion of the preset first observation algorithm and the preset second observation algorithm using a weighted average method to obtain the fused observation algorithm; and using the fused observation algorithm, the fused estimated speed of the motor is calculated according to the following formula:

[0015] ω e =k2*ω magnetic +(1-k2)*ω sliding ;

[0016] Where, ω e The fusion estimated speed of the motor is given by k2, which is a preset weighting coefficient and 0 ≤ k2 ≤ 1; ω magnetic To obtain the first estimated speed of the motor using a preset first observation algorithm, ω sliding The second estimated speed of the motor is obtained by using a preset first observation algorithm.

[0017] In some implementations, the preset first observation algorithm includes a flux linkage observer algorithm; and the preset second observation algorithm includes a synovial observer algorithm.

[0018] In conjunction with the above method, another aspect of the present invention provides a motor control device, wherein the motor control system has a current loop and a speed loop; the motor control device includes: a control unit configured to inject a preset voltage signal into the d-axis voltage of the speed loop before the motor starts; an acquisition unit configured to acquire the initial position of the rotor in the motor; the control unit is further configured to set a target current of the d-axis of the current loop, a target speed of the motor, and a position observation algorithm of the speed loop based on the initial position of the rotor in the motor, and control the motor to start and run in a zero-speed closed loop; the acquisition unit is further configured to acquire the speed of the motor; the control unit is further configured to switch the target current of the d-axis of the current loop and switch the position observation algorithm of the speed loop according to the speed of the motor, and continue to control the closed-loop operation of the motor.

[0019] In conjunction with the above-described device, the present invention further provides a motor controller and a motor, comprising: the motor control device described above.

[0020] In conjunction with the above-described device, the present invention further provides a motor, comprising: the motor control device described above, or the motor controller described above.

[0021] In conjunction with the above method, the present invention further provides a storage medium comprising a stored program, wherein, when the program is executed, the device on which the storage medium is located executes the steps of the motor control method described above.

[0022] In conjunction with the above method, the present invention further provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the motor control method described above.

[0023] The present invention addresses a motor (e.g., a permanent magnet synchronous motor) control system. The control system includes a current loop and a speed loop. Before starting the motor, a preset voltage signal is injected into the d-axis voltage of the speed loop to generate three-phase currents in the motor's three-phase windings. The initial position of the rotor is obtained. Based on this initial rotor position, a target d-axis current and a target speed of the motor are set, along with a position observation algorithm for the speed loop. This allows for zero-speed closed-loop startup and operation of the motor. The motor speed is then acquired. Based on the motor speed, the target d-axis current and the position observation algorithm of the speed loop are switched to continue controlling the motor's closed-loop operation. Thus, by controlling the motor to start at zero speed in a closed loop when starting the motor (e.g., a permanent magnet synchronous motor), such as detecting the initial rotor position by injecting a voltage vector (e.g., a square wave voltage vector) when the motor is stationary, and setting the d-axis current i at zero speed... d The value is positive; and the observation algorithm is smoothly switched during the motor's acceleration from standstill. Different observation algorithms (such as flux linkage observer algorithm and sliding mode observation algorithm) are used for different speed ranges, and a speed transition zone is set to achieve efficient sensorless control of the motor (such as a permanent magnet synchronous motor) across the entire speed range, avoiding mechanical reversal during motor startup and improving motor reliability. This motor controller relates to the manufacturing of power electronic components.

[0024] Specifically, in the solution of this invention, for the motor (such as a permanent magnet synchronous motor) control system, the motor control system is a dual closed-loop control system with a current loop and a speed loop; when the motor is stationary before starting, a preset voltage signal (such as injecting a square wave voltage signal V) is injected into the d-axis voltage of the speed loop. inj After that, the three-phase current of the motor is detected, and the position of the motor rotor is calculated as the initial position of the motor rotor; after obtaining the initial position of the motor rotor, while the motor is still stationary (i.e., the motor is at zero speed), the target value of the d-axis current i of the current loop is set. dref =The given current i during the motor starting phase dstart (i dstart >0), given the reference speed n of the motor rotor ref The position observation algorithm uses a flux linkage observer to control the motor in a closed-loop operation. During the closed-loop operation of the motor, the motor speed n observed by the flux linkage observer is obtained. e The motor speed n observed by the flux linkage observer e Greater than or equal to the preset speed threshold n th In this case, let the target value of the d-axis current of the current loop be i. dref =0, in the preset speed transition zone [minimum speed ω]th Maximum speed ω high Within, the observed electric angular velocity ω is determined by the magnetic flux observer algorithm. magnetic The observed electric angular velocity ω of the sliding mode observation algorithm sliding The estimated motor speed ω is obtained by weighted average calculation. e The position observation algorithm employs the sliding diaphragm observer algorithm, based on the estimated motor speed ω. e The motor speed n is obtained through speed calculation. e This participates in the calculation of the speed loop, enabling efficient sensorless control of the permanent magnet synchronous motor across its entire speed range. Thus, by detecting the initial rotor position of the motor (such as a permanent magnet synchronous motor) through the injection of a voltage vector (such as a square wave voltage vector) when the motor (such as a permanent magnet synchronous motor) starts and when the motor is stationary, the d-axis current i is set at zero speed. d To achieve a positive value, a flux linkage observer algorithm and a sliding mode observer algorithm are used as observation algorithms for different speed ranges, and a speed transition zone is set to realize efficient sensorless control of the motor (such as a permanent magnet synchronous motor) across the entire speed range. This avoids mechanical reversal during motor startup and improves motor reliability. This motor controller relates to the manufacturing of power electronic components.

[0025] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention.

[0026] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0027] Figure 1 This is a flowchart illustrating an embodiment of the motor control method of the present invention;

[0028] Figure 2 This is a flowchart illustrating an embodiment of the method of the present invention for obtaining the initial position of the rotor in the motor;

[0029] Figure 3 This is a flowchart illustrating an embodiment of the method of the present invention for controlling the zero-speed closed-loop start-up and operation of the motor;

[0030] Figure 4 This is a flowchart illustrating an embodiment of the method of the present invention that continues to control the closed-loop operation of the motor;

[0031] Figure 5 This is a flowchart illustrating an embodiment of the method of the present invention in which the position observation algorithm of the rotational speed ring is smoothly switched from a preset first observation algorithm to a preset second observation algorithm;

[0032] Figure 6This is a schematic diagram of a structure of an embodiment of the motor control device of the present invention;

[0033] Figure 7 A schematic diagram of the sensorless vector control process for a permanent magnet synchronous motor;

[0034] Figure 8 This is a schematic flowchart of an embodiment of a sensorless zero-speed closed-loop start and full-speed-domain control method for a motor (such as a permanent magnet synchronous motor);

[0035] Figure 9 A schematic diagram of the sensorless vector control process for a permanent magnet synchronous motor that injects a high-frequency square wave signal at zero speed.

[0036] Figure 10 In sensorless vector control of a permanent magnet synchronous motor that injects a high-frequency square wave signal at zero speed, a voltage signal V is injected. inj PWM signal, injected voltage signal V inj and stator current harmonic signal I ripple A schematic diagram of the curve;

[0037] Figure 11 This is a schematic diagram of the phase-locked loop's working process;

[0038] Figure 12 This is a schematic diagram of the sensorless vector control process for a permanent magnet synchronous motor using a position observer based on magnetic flux linkage.

[0039] Referring to the accompanying drawings, the reference numerals in the embodiments of the present invention are as follows:

[0040] 102 - Acquisition unit; 104 - Control unit. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0042] Considering that the sensorless control method in the motor (such as permanent magnet synchronous motor) control system of the relevant scheme is prone to mechanical reversal during motor startup, affecting motor reliability. Specifically, the sensorless scheme in the relevant scheme has a fatal flaw in the zero-speed load startup stage - it is prone to mechanical reversal, switching jitter and startup failure due to position observation error, which seriously restricts its practical application in high reliability scenarios.

[0043] For example, when a permanent magnet synchronous motor is used in an industrial metal drawing machine or spinning machine, reverse rotation can easily break the fine filaments. Industrial high-speed air suspension motors rely on forward rotation to establish a gas hydrodynamic pressure effect to form an air film. Reverse rotation will disrupt the gas flow direction, causing the air film to fail to form, resulting in initial collision damage between the shaft and the bearing, and even causing the bearing foil to break. Therefore, the fewer times the air suspension bearing reverses during zero-speed start-up, the better. This requires the drive system to identify the rotor's initial position as accurately as possible.

[0044] The three-stage starting method is a common approach in motor control systems. After the rotor position is determined when the motor is stationary, an external synchronous starting method is used. The motor windings are energized sequentially according to a set order. At this time, the motor rotor is dragged up in the rotating magnetic field generated by the windings. Because the zero-speed stage relies on open-loop starting and the position observer is not activated, mechanical reversal is prone to occur when starting under load. Furthermore, the sudden change in control strategy during closed-loop switching causes severe jitter and oscillation. At the same time, the starting efficiency is low, the load-carrying capacity is weak, and the robustness to load changes is poor.

[0045] Therefore, the present invention proposes a motor control method, specifically a sensorless zero-speed closed-loop start and full-speed domain control method for a motor (such as a permanent magnet synchronous motor). This method employs a square wave voltage vector injection method to detect the rotor's initial position and uses the target value i of the d-axis current calculated by the motor controller. dref =The given current i during the motor starting phase dstart (i dstart >0) Provide flux compensation, using flux observer algorithm and sliding mode observation algorithm as observation algorithms for different speed ranges, and use weighted average method to achieve fusion of speed transition zone, thereby avoiding mechanical reversal when the motor starts and improving motor reliability.

[0046] According to an embodiment of the present invention, a method for controlling a motor is provided, such as... Figure 1 The diagram shows a flowchart of an embodiment of the method of the present invention. The control system of the motor has a current loop and a speed loop, and the motor is such as a permanent magnet synchronous motor; the speed observation algorithm of the motor in the control system includes: a preset flux linkage observer algorithm and a preset sliding film observer algorithm; the motor has a rotor and a stator, and the stator has three-phase windings. Figure 7 This is a schematic diagram of the sensorless vector control process for a permanent magnet synchronous motor. (Example:) Figure 7 As shown in the block diagram of sensorless vector control, vector control of a permanent magnet synchronous motor generally requires the acquisition of three-phase current i. a i b and i cSimultaneously, the three-phase currents obey Kirchhoff's current law, meaning the sum of the three-phase currents is zero. The sampled current is transformed to a two-phase stationary coordinate system via Clark transformation. The current i in the two-phase stationary coordinate system... α and i β High-performance decoupled control of the permanent magnet synchronous motor is achieved by transforming to a synchronous rotating coordinate system via Park transformation. The reference speed n of the speed loop... ref The estimated electric rotational speed ω by the position observer algorithm e The calculated rotational speed n e This constitutes a feedback error, which, after passing through a PI controller, outputs a quadrature-axis current (i.e., the q-axis current i). q Reference value i qref Reference value i for quadrature-axis current. qref and the sampled value i of the quadrature axis current q This constitutes the q-axis feedback error and the direct-axis current (i.e., the d-axis current i). d Reference value i dref and the sampled value i of the direct-axis current d The d-axis feedback error is constructed, and the feedback error is used to form a current loop via a PI controller. The current loop outputs a command voltage U in a synchronous rotating coordinate system. d and U q Command voltage value U in synchronous rotating coordinate system d and U q Converted to voltage value U in two-phase stationary coordinate system via inverse Park transform α and U β Voltage value U in a two-phase stationary coordinate system α and U β The input is a space vector pulse width modulation (SVPWM) module. The SVPWM module outputs the three-phase duty cycle, which, through an inverter module, enables dual closed-loop control of the speed and current of the permanent magnet synchronous motor. The electrical angle input θ of the Park converter module and the Park inverse converter module is... e The location is observed and output online by a position observer. In the solution of this invention, as... Figure 1 As shown, the motor control method includes steps S110 to S150.

[0047] In step S110, when the motor needs to be started, before the motor starts, a preset voltage signal is injected into the d-axis voltage of the speed loop to generate the three-phase current of the motor in the three-phase windings; wherein, the preset voltage signal is such as a square wave voltage signal V. inj .

[0048] In step S120, the initial position of the rotor in the motor is obtained.

[0049] In step S130, based on the initial position of the rotor in the motor, the d-axis target current of the current loop is set, the target speed of the motor is set, and the position observation algorithm of the speed loop is set to control the zero-speed closed-loop start-up and operation of the motor; wherein, the d-axis target current of the current loop is as shown in the d-axis current target value i. dref The target speed of the motor is as given by the reference speed n. ref The position observation algorithm of the speed loop is used to observe and obtain the estimated speed ω of the motor. e Then, based on the estimated speed ω of the motor e The rotational speed n of the motor can be calculated. e .

[0050] In step S140, the rotational speed of the motor is obtained; the rotational speed of the motor is, for example, the estimated rotational speed ω of the motor observed by the flux linkage observer. e The calculated motor speed n e .

[0051] At step S150, the target current of the d-axis of the current loop is switched according to the speed of the motor, and the position observation algorithm of the speed loop is switched to continue controlling the closed-loop operation of the motor.

[0052] In the present invention, the control system of the motor has a current loop and a speed loop, and the motor is such as a permanent magnet synchronous motor. When the motor needs to be started, before the motor starts, a preset voltage signal is injected into the d-axis voltage of the speed loop to generate the three-phase current of the motor in the three-phase windings; the initial position of the rotor in the motor is obtained; based on the initial position of the rotor in the motor, the target current of the d-axis of the current loop is set, the target speed of the motor is set, and the position observation algorithm of the speed loop is set to control the motor to start and run in a zero-speed closed loop; the speed of the motor is obtained; according to the speed of the motor, the target current of the d-axis of the current loop is switched, and the position observation algorithm of the speed loop is switched to continue to control the closed-loop operation of the motor. Thus, by controlling the motor to start in a zero-speed closed loop when the motor (such as a permanent magnet synchronous motor) starts, such as detecting the initial position of the motor rotor by injecting a voltage vector (such as a square wave voltage vector) when the motor is stationary, and setting the d-axis current i when the motor is at zero speed. d The value is positive; and the observation algorithm is smoothly switched during the process of the motor from standstill to speed-up. For example, different observation algorithms (such as flux linkage observer algorithm and sliding mode observation algorithm) are used as observation algorithms for different speed ranges and speed transition zones are set to achieve efficient sensorless control of the motor (such as permanent magnet synchronous motor) across the entire speed range, avoid mechanical reversal when the motor starts, and improve motor reliability.

[0053] In some implementations, a preset voltage signal is included, including: a square wave voltage signal V. inj .

[0054] In step S110, injecting a preset voltage signal into the d-axis voltage of the rotational speed ring includes:

[0055] With the motor stationary, a square wave voltage signal V is injected into the d-axis voltage of the speed loop. inj This is to generate the three-phase current of the motor at the three-phase windings of the motor.

[0056] Figure 8 This is a flowchart illustrating an embodiment of a sensorless zero-speed closed-loop start and full-speed-domain control method for a motor (such as a permanent magnet synchronous motor). Figure 8 As shown, the sensorless zero-speed closed-loop start and full-speed domain control logic for a motor (such as a permanent magnet synchronous motor) includes:

[0057] Step 1 (i.e., Step 1) detects the initial position of the motor rotor to obtain the initial position of the motor rotor, and then proceeds to Step 2.

[0058] In step 1, when the motor is stationary, a square wave voltage signal V is injected into the direct axis (i.e., the d-axis). inj Since the rotor position affects the inductance, the current response will change with the rotor position. By detecting the DC component or harmonics of the motor stator current, the initial position of the motor rotor can be calculated.

[0059] In the solution of this invention, in the control of zero-speed load start and closed-loop start of the motor (such as permanent magnet synchronous motor), the square wave voltage vector injection method is used to detect the initial position of the rotor, which effectively avoids the mechanical reversal problem caused by inaccurate initial position angle and eliminates shaking and reversal.

[0060] In the scheme of this invention, a direct position closed-loop start method based on flux linkage observation is adopted: when the motor is stationary, a square wave voltage signal V is injected into the d-axis voltage of the speed loop. inj This method generates three-phase current in the three-phase windings of the motor. The initial rotor angle is obtained using a square wave injection method. With a positive direct-axis current and the starting speed determined by flux linkage observation, the motor can be directly started in a closed-loop manner. This solves the problems of initial angle uncertainty caused by flux linkage observation and DC bias caused by integral accumulation in related schemes.

[0061] In some implementations, the specific process of obtaining the initial position of the rotor in the motor in step S120 is described in the following exemplary description.

[0062] The following is combined with Figure 2The schematic diagram shown is a flowchart of an embodiment of the method of the present invention for obtaining the initial position of the rotor in the motor. The specific process of obtaining the initial position of the rotor in the motor in step S120 is further explained, including steps S210 to S220.

[0063] Step S210: Based on the preset voltage signal injected into the d-axis voltage of the speed ring, the three-phase current of the motor is obtained, specifically, the three-phase current generated at the three-phase windings of the motor is obtained.

[0064] Step S220: Based on the three-phase current of the motor, determine the rotational speed and angle of the rotor in the motor through the current loop, and use them as the initial position of the rotor in the motor.

[0065] Figure 9 A schematic diagram of the sensorless vector control process for a permanent magnet synchronous motor that injects a high-frequency square wave signal at zero speed. Figure 9 In this context, HFI stands for High-Frequency Signal Injection, and BPF stands for Bandpass Filter. BPF refers to bandpass filtering of the sampled q-axis current; HFI refers to high-frequency injection control measurement. Figure 9 Simplified Chinese illustration. Figure 10 In sensorless vector control of a permanent magnet synchronous motor that injects a high-frequency square wave signal at zero speed, a voltage signal V is injected. inj PWM signal, injected voltage signal V inj and stator current harmonic signal I ripple A schematic diagram of the curve. V inj To inject a square wave voltage signal along the d-axis, the voltage level flips between positive and negative values ​​each PWM cycle (in up-down mode, the count increases and then decreases each cycle), thus obtaining the stator current signal I. ripple .like Figure 9 and Figure 10 At zero speed, a high-frequency square wave signal V is injected to create positive and negative injection voltage signals. inj Inject voltage signal V inj The injection frequency is increased to half the PWM switching frequency, and the injected voltage signal V inj This is superimposed on the d-axis voltage. This results in significant current ripples in the stator current, which carry positional information as the inductance of the stator windings changes. The sampled three-phase currents are then transformed to obtain the q-axis current I. q High-frequency injection demodulation is performed to obtain the motor rotor speed and angle, thereby obtaining the initial position of the motor rotor.

[0066] like Figure 8As shown, the sensorless zero-speed closed-loop start and full-speed domain control logic for a motor (such as a permanent magnet synchronous motor) also includes: in step 1, transforming the sampled three-phase current to obtain the q-axis current I. q The derivation process of obtaining the motor rotor speed and angle through high-frequency injection demodulation:

[0067] Injected voltage signal V inj As shown in the following formula:

[0068] (1);

[0069] Therefore:

[0070] (2);

[0071] (3).

[0072] in, This represents the actual position of the motor rotor. The difference between the sampling times. This represents the difference between the moment before and the moment after sampling the high-frequency current. High-frequency components injected along the d and q axes, respectively, V inj V represents the amplitude of the injected square wave voltage. squ L is the amplitude constant of the injected square wave voltage. s This is the inductance of the motor stator.

[0073] When the frequency of the injected high-frequency signal is much higher than the rated frequency of the motor, the stator resistance will be much smaller than the high-frequency inductive reactance. The impedance voltage drop can be ignored in the high-frequency voltage model, and the speed will be zero. In summary, we can conclude... The equations in the coordinate system are:

[0074] (4).

[0075] in, The average inductance of the motor stator winding, It is the half-differential inductance of the motor stator winding. For the actual rotating coordinate system, To estimate the coordinate system, the high-frequency voltage component u and the high-frequency current component i are also values ​​in the estimated coordinate system. This represents the actual position of the motor rotor. Estimate the position of the motor rotor. This represents the positional angle deviation. To estimate the change in high-frequency ripple current along the d-axis in the coordinate system, To estimate the change in high-frequency ripple current along the q-axis in the coordinate system. To estimate the high-frequency ripple voltage variation along the d-axis in the coordinate system, To estimate the high-frequency ripple voltage change along the q-axis in the coordinate system.

[0076] Substituting equation (3) into equation (4), we get:

[0077]

[0078] (5).

[0079] In the scheme of this invention, the position observation method is as follows: From the above formula, it can be deduced that when a high-frequency square wave voltage signal is injected into the d-axis of the estimated coordinate system, a current signal twice the angle deviation can be obtained from the q-axis of the estimated coordinate system. This q-axis current can then be used to establish a loop, continuously correcting the position of the estimated coordinate system until the q-axis current is zero. At this point, the estimated coordinate system coincides with the actual coordinate system. The position observer can be a phase-locked loop. After obtaining the rotor angle, polarity determination is required, i.e., the d-axis direction determination. This can be achieved by detecting the different peak values ​​of the current response generated by equal-width voltage pulses, thus determining the positive direction of the d-axis. That is, injecting +V pulses of equal duration into the d-axis... inj and -V inj The corresponding real-time d-axis current id is obtained respectively. se (+) and id se (-), determine the absolute value of the two injected currents, if id se (+) > id se If (-), then the angle of observation at the rising position needs to be increased by 180°; otherwise, the observation angle can be used directly.

[0080] In step 1, the rotor position angle in the stationary state before startup can be directly obtained through the above method. Specifically, it is based on the preset voltage signal injected into the d-axis voltage of the speed loop to obtain the three-phase current of the motor, specifically the three-phase current generated at the three-phase windings of the motor. Based on the three-phase current of the motor, the rotational speed and angle of the rotor in the motor are determined through the current loop as the initial position of the rotor in the motor. This ensures that the motor starts at its actual angle, avoiding possible reverse starting problems caused by unknown position angle at the moment of startup.

[0081] In some embodiments, the position observation algorithm of the rotational speed ring includes: a preset first observation algorithm, such as a flux linkage observer observation algorithm.

[0082] In step S130, based on the initial position of the rotor in the motor, the target current of the d-axis of the current loop is set, the target speed of the motor is set, and the position observation algorithm of the speed loop is set. The specific process of controlling the zero-speed closed-loop start-up and operation of the motor is described in the following exemplary description.

[0083] The following is combined with Figure 3 The flowchart shown is a schematic diagram of an embodiment of the method of the present invention for controlling the zero-speed closed-loop start and operation of the motor. It further illustrates the specific process of controlling the zero-speed closed-loop start and operation of the motor in step S130, including steps S310 to S320.

[0084] Step S310: Set the target current of the d-axis of the current loop to a positive value, give the target speed of the motor in the speed loop, and set the position observation algorithm of the speed loop to use a preset first observation algorithm.

[0085] Step S320: Based on the initial position of the rotor in the motor, and with the motor speed at zero, control the motor to start in a zero-speed closed loop.

[0086] like Figure 8 As shown, the sensorless zero-speed closed-loop start and full-speed domain control logic for a motor (such as a permanent magnet synchronous motor) also includes: Step 2, after obtaining the initial position of the motor rotor, setting the target value i of the d-axis current calculated by the motor controller when the motor is at zero speed. dref =The given current i during the motor starting phase dstart (i dstart >0), given the target speed of the motor rotor, i.e., the given reference speed n ref The position observation algorithm uses a flux linkage observer to control the motor in closed-loop operation until the motor speed n e ≥ a certain speed threshold n th Next, proceed to step 3.

[0087] The injected voltage is along the d-axis, and since this voltage is relatively small, it doesn't generate a rotational force field and therefore won't cause the motor to rotate. Thus, the motor reaches zero speed after the square wave voltage is injected. Speed ​​threshold n th It is generally set to 0.1 to 0.2 times the rated speed of the motor.

[0088] In the solution of this invention, in the control of zero-speed load start-up and closed-loop start-up of a motor (such as a permanent magnet synchronous motor), based on the initial position of the rotor in the motor, the target current of the d-axis of the current loop is set, the target speed of the motor is set, and the position observation algorithm of the speed loop is set to control the zero-speed closed-loop start-up and operation of the motor. The initial angle of the motor rotor is obtained by the square wave injection method, and the direct-axis current is given a positive value. The starting speed is obtained by flux linkage observation as the position, thereby realizing the direct closed-loop start-up of the motor. Furthermore, the flux linkage observer algorithm and the sliding mode observation algorithm are used as observation algorithms for different speed ranges, which effectively improves the observation accuracy of the motor rotor position information, improves the efficiency at medium and high speeds, and achieves high-efficiency operation.

[0089] In some implementations, step S310, setting the d-axis target current of the current loop to a positive value, includes:

[0090] Set the d-axis target current i of the current loop. dref A starting current i is given to the d-axis of the motor. dstart And the starting current i of the d-axis of the motor dstart >0.

[0091] In the solution of this invention, in the control of zero-speed load start-up and closed-loop start-up of a motor (such as a permanent magnet synchronous motor), the target value i of the d-axis current calculated by the motor controller is used. dref =The given current i during the motor starting phase dstart (i dstart >0) Provides flux compensation, generating a more stable starting torque, helping the motor to start smoothly under load at zero speed, and enhancing the stability of the motor control system; that is:

[0092] ;

[0093] In the dq rotating coordinate system of a three-phase motor, the d-axis is typically defined as the direction coinciding with the magnetic field of the rotor's permanent magnet, while the q-axis leads the d-axis by 90 electrical degrees. According to motor principles, electromagnetic torque is primarily generated by the q-axis current iq (quadrature-axis current), while the d-axis current id (direct-axis current) is mainly used to control the magnetic flux. dref This is the target d-axis current value calculated by the motor controller, i.e., the desired current value flowing through the motor on the d-axis; i dstart It is the given current during the motor startup phase.

[0094] The present invention addresses the problem that most sensorless position observation algorithms in motor control systems are prone to mechanical reversal during zero-speed load start-up and closed-loop start-up of motors (such as permanent magnet synchronous motors). It proposes a sensorless zero-speed closed-loop start-up and full-speed-domain control scheme for motors (such as permanent magnet synchronous motors). This scheme uses a square wave voltage vector injection method to detect the rotor's initial position and employs the target value i of the d-axis current calculated by the motor controller. dref =The given current i during the motor starting phase dstart (i dstart >0) Provides flux compensation, uses flux observer algorithm and sliding mode observation algorithm as observation algorithms for different speed ranges, and uses weighted average method to realize the fusion of speed transition zone, realizes efficient sensorless control of motor (such as permanent magnet synchronous motor) across the entire speed range, avoids mechanical reversal when the motor starts, and improves motor reliability.

[0095] In some implementations, step S310, setting the d-axis target current of the current loop to a positive value, further includes: calculating the d-axis starting current i of the motor according to the following formula. dstart :

[0096] Among them, i dstart =k1*i rated ;

[0097] k1 is a preset calculation coefficient, and 0 < k1 < 1; i rated The rated current of the motor is given.

[0098] like Figure 8 As shown, the sensorless zero-speed closed-loop start and full-speed domain control logic for a motor (such as a permanent magnet synchronous motor) further includes: in step 2, after obtaining the initial position of the motor rotor, at zero speed, based on vector control, setting the direct-axis current reference value to a positive value, i.e., the target value i of the d-axis current calculated by the motor controller. dref =The given current i during the motor starting phase dstart (i dstart >0), normally, setting i dstart =0.1*i rated Among them, i dref i is the reference value for the direct-axis current. dstart For the direct-axis starting current, i rated This is the rated current of the motor. A reference speed n is given. ref The observed electrical angular velocity and observed position angle, obtained by the flux linkage observer algorithm, are used as feedback for the velocity loop and electrical angle inputs for the Park transform and inverse Park transform modules, respectively, to control the closed-loop operation of the motor and allow the motor speed n to reach its maximum. e From 0 to a certain speed threshold n th .

[0099] Control the motor to operate in a closed loop until the motor speed n e ≥ a certain speed threshold n th The derivation process:

[0100] Flux linkage estimation process: The stator voltage equation in the coordinate system is:

[0101] (6).

[0102] in, , , , It is the specific mapping of voltage and current on the α and β axes, R s D represents the stator resistance component, and D is the differential operator. For inductance (subscript) (representing the direct axis and quadrature axis components respectively). ω is the permanent magnet flux linkage, ω is the rotor electric angular frequency, and θ is the rotor angle.

[0103] Formula (6) can be simplified as:

[0104] (6-1).

[0105] Formula (6-1) is a simplified version of formula (6), which is a matrix-vector relationship. , , , These represent the stator flux linkages mapped onto the α and β coordinate systems, respectively.

[0106] in:

[0107] (7).

[0108] have:

[0109] (8);

[0110] (9).

[0111] In the formula: This is the stator flux linkage vector.

[0112] Based on equations (6-1) and (8), the state-space expression with the extended flux linkage as the state variable is constructed as follows:

[0113] (10).

[0114] In the formula, This is the output vector.

[0115] Within the electrical time constant range, equation (10) can be considered as a steady system, so the expression for constructing the extended flux linkage state observer is:

[0116] (11).

[0117] In the formula: and They are respectively and The observed values, and All are actual values; Here is the feedback gain matrix, where and These are coefficients to be determined.

[0118] Comparing equations (10) and (11), the extended flux linkage observation error equation can be obtained as follows:

[0119] (12).

[0120] I is the identity matrix.

[0121] To improve the stability and robustness of the observer, the poles of the differential equation shown in equation (12) can be configured to be the same negative real number, such as -ρ (i.e., negative ρ), thus obtaining the feedback gain matrix as:

[0122] (13).

[0123] If the observer structure is designed directly according to the form of equation (11), then the stator current needs to be differentiated, which can easily cause noise. Therefore, an intermediate variable is introduced:

[0124] (14);

[0125] Right now:

[0126] (14-1).

[0127] There are multiple methods for observing flux linkage; the derivation above is just one example. Besides the methods mentioned above, flux linkage can also be observed using a full-dimensional flux linkage observer, a flux linkage integrator, or other methods. The key is to substitute the flux linkage obtained from the observer into the current flux linkage equation below and lock in the phase to determine the angle.

[0128] Substituting the flux linkage obtained from the above observer into the following current flux linkage equation, the motor speed is obtained by phase-locking the angle. The workflow equation of the state observer is as follows:

[0129] (15).

[0130] Figure 11 This is a schematic diagram of the phase-locked loop's (PLL) workflow. Figure 11 The block diagram of phase-locked loop principle shown: The motor rotor angle is orthogonally demodulated into a proportional error signal, and then PI is applied to obtain the motor rotor speed.

[0131] like Figure 11 As shown, , , , It is the specific mapping of voltage and current on the α and β axes, where Ls represents the stator inductance. , These represent the stator flux linkage components mapped to the α and β coordinate systems, respectively. The flux linkage in the α and β coordinate systems is obtained through the flux linkage observer. , Then, substituting this into the current equation for the magnetic flux linkage, we obtain the angled equation. , Then, phase locking of the angle is performed to obtain... ,because The angle difference can be obtained by performing PI (i.e., Kp + Ki / s) processing on the angle difference to obtain the angular frequency ω. ω is then passed through an integrator (i.e., 1 / s) to obtain the angle θ. The PI controller acts as a loop filter, and the integrator acts as a voltage-controlled oscillator. This is the classic PLL phase-locked loop control process.

[0132] Figure 12 This is a schematic diagram of the sensorless vector control process for a permanent magnet synchronous motor using a flux linkage-based position observer. After obtaining the initial rotor position (via HFI), at zero motor speed, based on... Figure 12 The vector control block diagram shown sets the direct axis (d-axis) current reference value to a positive value, i.e., where, This is a reference value for the direct-axis current. For direct-axis starting current, The rated current of the motor is used. The flux linkage position observation algorithm obtains the observed electrical angular velocity and observed position angle, which are used as feedback for the speed loop and electrical angle inputs for the Park transform and inverse Park transform modules, respectively, to control the closed-loop operation of the motor, allowing the motor speed to increase from 0 to a certain speed threshold. In the vector control of this invention, the angle directly using the position observation algorithm at zero speed is the velocity, and a current needs to be directly superimposed on the d-axis to achieve startup.

[0133] like Figure 12 As shown, the initial rising angle θ uses the angle signal obtained in the first step, and during the startup process, a d-axis current with a positive reference value needs to be given on the d-axis of the estimated coordinates, that is:

[0134] .

[0135] In the solution of this invention, the target value i of the d-axis current calculated by the motor controller is used. dref =The given current i during the motor starting phase dstart (i dstart >0) Provides flux linkage compensation, specifically based on i dstart =k1*i rated The starting current i of the motor's d-axis is calculated. dstart k1 is a preset calculation coefficient, and 0 < k1 < 1; i ratedThe rated current of the motor is given; thus, the initial angle of the motor rotor is obtained by square wave injection method, and the direct axis current is given a positive value. The starting speed is obtained by magnetic flux observation, thereby realizing the direct closed-loop starting of the motor.

[0136] In this invention, a high-frequency injection method is used to obtain the initial angle. A position observer based on magnetic flux is applied to observe the motor rotor position. This observation, independent of back electromotive force, enables accurate position observation at low speeds. Simultaneously, it avoids potential control instability caused by directly injecting a high-frequency signal and superimposing it with a high-frequency current during startup, which would result in additional current ripple and torque fluctuations after high-frequency injection startup. Furthermore, since the initial angle is known, direct startup without reverse rotation can be achieved, avoiding the positioning reversal problem and the failure to switch from open-loop to closed-loop operation caused by the three-stage positioning + open-loop + closed-loop method in related solutions.

[0137] In some implementations, in step S150, the target current of the d-axis of the current loop is switched according to the speed of the motor, and the position observation algorithm of the speed loop is switched to continue controlling the closed-loop operation of the motor. For details, please refer to the following exemplary description.

[0138] The following is combined with Figure 4 The schematic diagram shown is a flowchart of an embodiment of the method of the present invention for continuing to control the closed-loop operation of the motor. It further illustrates the specific process of continuing to control the closed-loop operation of the motor in step S150, including steps S410 to S420.

[0139] Step S410: Determine whether the motor speed is greater than or equal to a preset first speed threshold; wherein, the motor speed is as follows: motor speed n e A preset first speed threshold, such as a certain speed threshold n. th .

[0140] Step S420: If it is determined that the motor speed is greater than or equal to a preset speed threshold, then the d-axis target current of the current loop is switched, and the position observation algorithm of the speed loop is switched, continuing to control the motor to operate in closed loop. If it is determined that the motor speed is not greater than or equal to the preset speed threshold, then the d-axis target current of the current loop is not switched, and the position observation algorithm of the speed loop is not switched; that is, based on the initial position of the rotor in the motor, the d-axis target current of the current loop is set, the target speed of the motor is set, and the position observation algorithm of the speed loop is set, controlling the motor to start and run in zero-speed closed loop.

[0141] like Figure 8 As shown, the sensorless zero-speed closed-loop start and full-speed domain control logic for a motor (such as a permanent magnet synchronous motor) also includes: Step 3, which controls the motor to run in closed loop until the motor speed n...e ≥ a certain speed threshold n th Then, the target value i of the d-axis current calculated by the motor controller is... dref =0, the weighted average method is used to achieve the fusion of the speed transition zone, the observation algorithm is switched to the sliding diaphragm observer algorithm, and the motor is controlled to operate in closed loop.

[0142] In the solution of this invention, in the control of zero-speed load start and closed-loop start of a motor (such as a permanent magnet synchronous motor), a square wave high-frequency pulse is first injected to detect the initial angle of the motor, and then the closed-loop start is directly achieved through the flux linkage observation method. For example, according to the speed of the motor, the d-axis target current of the current loop is switched, and the position observation algorithm of the speed loop is switched to continue controlling the closed-loop operation of the motor. At this time, it is necessary to compensate the positive direct axis current for flux linkage compensation to enhance the stability of the low-speed magnetic field. The method of smoothly switching to the sliding mode observer at medium and high speeds solves the problem of sensorless control being prone to step loss due to weak signal at zero speed load, and achieves the technical effect of accurate phase tracking, smooth dynamic acceleration and no step loss in the entire speed range of sensorless control.

[0143] In some implementations, in step S420, if it is determined that the motor speed is greater than or equal to a preset speed threshold, the d-axis target current of the current loop is switched, and the position observation algorithm of the speed loop is switched to continue controlling the closed-loop operation of the motor, including:

[0144] If it is determined that the speed of the motor is greater than or equal to a preset speed threshold, the d-axis target current of the current loop is switched from being positive to being zero, and the position observation algorithm of the speed loop is smoothly switched from a preset first observation algorithm to a preset second observation algorithm, so as to continue to control the closed-loop operation of the motor.

[0145] This invention proposes a sensorless zero-speed closed-loop start and full-speed domain control scheme for motors (such as permanent magnet synchronous motors). It solves the problem that most sensorless position observation algorithms in related schemes are prone to mechanical reversal during zero-speed load start and closed-loop start of permanent magnet synchronous motors. The main steps include: 1) Initial rotor position detection: Detecting the initial rotor position by injecting a square wave voltage vector; 2) At zero speed, based on vector control, setting the direct-axis current (i.e., the d-axis current i). d The value is positive, meaning it represents the target value of the d-axis current i calculated by the motor controller. dref =The given current i during the motor starting phase dstart (i dstart >0), given a reference rotational speed n refThe observed electric angular velocity and observed position angle are obtained by the flux linkage observer algorithm and used as feedback for the velocity loop and current loop to control the closed-loop operation of the motor, allowing the motor speed to increase from 0 to a certain speed threshold n. th 3) Determine whether the observed electric angular velocity has reached the rotational speed threshold n. th If satisfied, then set the target value i of the d-axis current calculated by the motor controller to... dref =0, switch the standard d-axis current i d =0 control, the position observer algorithm is switched from the flux observer algorithm suitable for zero and low speed to the sliding mode observer algorithm suitable for medium and high speed; 4) Due to the differences between the two control methods, direct switching will cause motor jitter problem. The weighted average method is used to realize the fusion of the speed transition zone; thereby realizing the purpose of the motor to start smoothly and directly from the stationary zero speed state and start under load.

[0146] In the solution of this invention, in the control of zero-speed load start and closed-loop start of a motor (such as a permanent magnet synchronous motor), when it is determined that the speed of the motor is greater than or equal to a preset speed threshold, the d-axis target current of the current loop is switched, and the position observation algorithm of the speed loop is switched to continue controlling the closed-loop operation of the motor. In this way, a control scheme for zero-speed sensorless direct closed-loop start is adopted, which solves the mechanical reversal problem caused by inaccurate initial position angle of the motor, realizes the smooth start of the motor in a strictly predetermined direction, eliminates the risk of start-up jitter and reversal, and improves the reliability of the motor.

[0147] In some embodiments, the position observation algorithm of the rotational speed ring includes: a preset first observation algorithm and a preset second observation algorithm, wherein the preset first observation algorithm is such as a flux linkage observer observation algorithm and the preset second observation algorithm is such as a sliding membrane observer observation algorithm.

[0148] In step S420, when it is determined that the speed of the motor is greater than or equal to a preset speed threshold, the specific process of smoothly switching the position observation algorithm of the speed loop from a preset first observation algorithm to a preset second observation algorithm is described in the following exemplary description.

[0149] The following is combined with Figure 5 The flowchart shown is a schematic diagram of an embodiment of the method of the present invention in which the position observation algorithm of the speed ring is smoothly switched from a preset first observation algorithm to a preset second observation algorithm. The specific process of smoothly switching the position observation algorithm of the speed ring from the preset first observation algorithm to the preset second observation algorithm in step S420 is further explained, including steps S510 to S530.

[0150] Step S510: If it is determined that the motor speed is less than a preset speed threshold, a preset first observation algorithm is used as the position observation algorithm for the speed loop; if it is determined that the motor speed is greater than or equal to the preset speed threshold, it is determined whether the motor speed is less than a preset second speed threshold; wherein, the preset second speed threshold is greater than the preset first speed threshold; the preset first speed threshold is based on the estimated motor speed ω. th The determined motor speed, and a preset second speed threshold such as based on the estimated motor speed ω. high The determined motor speed.

[0151] Step S520: If it is determined that the motor speed is greater than or equal to a preset speed threshold, and if it is determined that the motor speed is less than a preset second speed threshold, then if it is determined that the motor speed is greater than or equal to a preset first speed threshold and less than a preset second speed threshold, then the preset first observation algorithm and the preset second observation algorithm are weighted and fused to obtain a fused observation algorithm, which is used as the position observation algorithm of the speed loop.

[0152] Step S530: If it is determined that the motor speed is greater than or equal to a preset speed threshold, and if it is determined that the motor speed is greater than or equal to a preset second speed threshold, then a preset second observation algorithm is used as the position observation algorithm for the speed loop.

[0153] In the solution of this invention, in the control of zero-speed load start and closed-loop start of a motor (such as a permanent magnet synchronous motor), a weighted average method is used to achieve the fusion of the speed transition zone. For example, when it is determined that the speed of the motor is greater than or equal to a preset speed threshold, the position observation algorithm of the speed loop is smoothly switched from a preset first observation algorithm to a preset second observation algorithm. The transition is smoother, suppressing the oscillation of motor current and torque, which can better meet the actual engineering requirements and achieve efficient sensorless control of the motor across the entire speed range.

[0154] In some implementations, step S520 involves weighted fusion of a preset first observation algorithm and a preset second observation algorithm to obtain a fused observation algorithm, including:

[0155] Based on the weighted average method, a weighted fusion of the preset first observation algorithm and the preset second observation algorithm is obtained to obtain a fused observation algorithm; using the fused observation algorithm, the fused estimated speed of the motor is calculated according to the following formula:

[0156] ω e =k2*ω magnetic +(1-k2)*ω sliding ;

[0157] Where, ω e The fusion estimated speed of the motor is given by k2, which is a preset weighting coefficient and 0 ≤ k2 ≤ 1; ω magnetic To obtain the first estimated speed of the motor using a preset first observation algorithm, ω sliding The second estimated speed of the motor is obtained by observing using a preset first observation algorithm. The preset weighting coefficient k2 is similar to the weighting coefficient α(ω).

[0158] like Figure 8 As shown, the sensorless zero-speed closed-loop start and full-speed domain control logic for a motor (such as a permanent magnet synchronous motor) also includes: in step 3, determining whether the observed electrical angular velocity of the motor rotor (i.e., the motor speed n) is satisfied. e ) Reaching this speed threshold n th If satisfied, then set the target value i of the d-axis current calculated by the motor controller to... dref =0, switch the standard d-axis current i d =0 control: The position observer algorithm is switched from the flux linkage observer algorithm suitable for zero-low speed to the sliding mode observer algorithm suitable for medium-high speed. The observed electrical angular velocity and observed position angle obtained by the sliding mode observation algorithm are used as feedback for the speed loop and electrical angle inputs for the Park transform and inverse Park transform modules, respectively. The smooth switching between the flux linkage observer algorithm in the zero-low speed region and the sliding mode observation algorithm in the medium-high speed region is crucial for the smooth operation of the motor across its entire speed range. When switching between the two different position estimation methods, the rotor speed and rotor position estimation values ​​must remain consistent before and after the switch; otherwise, a current surge may occur during the switching instant. Therefore, a weighted average method is used to achieve fusion in the speed transition region.

[0159] The weighted average method is used to achieve the fusion of the speed transition zone, including:

[0160] Define the speed range ω of the speed transition zone. transition =[Minimum RPM ω th Maximum speed ω high The estimated rotational speed ω in this range e The observed electric angular velocity ω by the flux linkage observer algorithm magnetic The observed electric angular velocity ω of the sliding mode observation algorithm sliding The weighted average is calculated as follows:

[0161] (16).

[0162] Wherein, the weighting coefficient α(ω) satisfies:

[0163] When ω≤ω th When α(ω) = 1, we use magnetic flux linkage for observation. th =nth *2π / 60.

[0164] ω is a given electrical angular frequency, which is also a given rotational speed; ω e It is the real-time electrical angular frequency.

[0165] Thus, at low speeds, due to the low back EMF of the motor, the position observation methods in related schemes rely on the magnitude of the back EMF, which is prone to inaccurate observation. Therefore, the flux linkage observation method is adopted, which mainly relies on the resistance R of the motor windings. s and the inductance L of the motor windings d L q Therefore, this method is more suitable for low-speed applications.

[0166] When ω≥ω high When α(ω) = 0, sliding mode observation is used entirely. Thus, at high speeds, better motor stability is required; therefore, a robust sliding mode observer is employed to achieve full-range speed and position observation.

[0167] In the solution of this invention, a weighted average method is used to perform weighted fusion of a preset first observation algorithm and a preset second observation algorithm to obtain a fused observation algorithm. In this way, in the control of zero-speed load start-up and closed-loop start-up of a motor (such as a permanent magnet synchronous motor), the weighted average method is used to achieve fusion of the speed transition zone, resulting in a smoother transition, suppressing the oscillation of motor current and torque, and realizing efficient sensorless control of the motor across the entire speed range.

[0168] This invention proposes a sensorless zero-speed closed-loop start and full-speed-range control scheme for motors (such as permanent magnet synchronous motors), which is versatile and applicable to other industries using permanent magnet synchronous motors. The sensorless zero-speed closed-loop start and full-speed-range control scheme for motors (such as permanent magnet synchronous motors) proposed in this invention effectively solves the problem of zero-speed load start-up of permanent magnet synchronous motors. It effectively avoids mechanical reversal caused by inaccurate initial position angles, eliminates jitter and reversal, and provides the initial angle required for start-up. The rotor operates in a closed-loop state throughout the entire process, from precise pre-positioning from rest, optimized acceleration, to smooth switching to the sliding mode observer algorithm. This ensures accurate commutation of the rotor during acceleration, preventing loss of steps or start-up failure. It exhibits good dynamic acceleration performance and adjustment capability, with a smoother transition, better meeting practical engineering needs and achieving efficient sensorless control of permanent magnet synchronous motors across the entire speed range.

[0169] In some implementations, the preset first observation algorithm includes a flux linkage observer algorithm; and the preset second observation algorithm includes a synovial observer algorithm.

[0170] In the solution of this invention, it is determined that the observed electrical angular velocity of the motor rotor (i.e., the motor speed n) is satisfied. e ) Reaching this speed threshold n th In this case, let the target value of the d-axis current i calculated by the motor controller be... dref =0, switch the standard d-axis current i d =0 control, the position observer algorithm is switched from the flux observer algorithm suitable for zero and low speed to the sliding mode observer algorithm suitable for medium and high speed. In this way, the flux observer algorithm in the zero and low speed region and the sliding mode observer algorithm in the medium and high speed region are switched smoothly, so that the rotor speed and rotor position estimates before and after the switch are consistent. Otherwise, it is easy to cause current surge at the moment of switching. To this end, a weighted average method is used to achieve the fusion of the speed transition region, the transition is relatively smooth, the oscillation of motor current and torque is suppressed, and efficient sensorless control of the motor across the entire speed range is achieved.

[0171] In this invention, addressing the problem that most sensorless position observation algorithms in related solutions are prone to mechanical reversal during zero-speed load start-up and closed-loop start-up of permanent magnet synchronous motors, a sensorless zero-speed closed-loop start-up and full-speed-range control scheme for motors (such as permanent magnet synchronous motors) is proposed. This scheme effectively solves the problem of zero-speed load-bearing permanent magnet synchronous motors, effectively avoids mechanical reversal caused by inaccurate initial position angles, eliminates jitter and reversal, provides the initial angle required for start-up, and ensures that the rotor operates in a closed-loop state throughout the entire process from precise pre-positioning at rest, optimized acceleration, and smooth switching to the sliding mode observer algorithm. This ensures accurate commutation of the rotor during acceleration, preventing step loss or start-up failure. It exhibits better dynamic acceleration performance and adjustment capability, with a smoother transition, better meeting practical engineering needs and achieving efficient sensorless control of permanent magnet synchronous motors across the entire speed range.

[0172] The technical solution of this embodiment addresses a motor (such as a permanent magnet synchronous motor) control system. The control system has a current loop and a speed loop. The motor, such as a permanent magnet synchronous motor, is used in this embodiment. Before starting the motor, a preset voltage signal is injected into the d-axis voltage of the speed loop to generate three-phase current in the motor's three-phase windings. The initial position of the rotor is obtained. Based on the initial rotor position, a target d-axis current of the current loop is set, a target speed of the motor is set, and a position observation algorithm for the speed loop is configured to control the motor to start and run in a zero-speed closed-loop manner. The motor speed is obtained. Based on the motor speed, the target d-axis current of the current loop is switched, and the position observation algorithm for the speed loop is switched to continue controlling the motor's closed-loop operation. Thus, by controlling the motor to start in a zero-speed closed-loop manner when the motor (such as a permanent magnet synchronous motor) starts, for example, detecting the initial rotor position by injecting a voltage vector (such as a square wave voltage vector) when the motor is stationary, and setting the d-axis current i at zero speed... d The value is positive; and the observation algorithm is smoothly switched during the motor's acceleration from standstill. Different observation algorithms (such as flux linkage observer algorithm and sliding mode observation algorithm) are used for different speed ranges, and a speed transition zone is set to achieve efficient sensorless control of the motor (such as a permanent magnet synchronous motor) across the entire speed range, avoiding mechanical reversal during motor startup and improving motor reliability. This motor controller relates to the manufacturing of power electronic components.

[0173] Specifically, in the solution of this invention, for the motor (such as a permanent magnet synchronous motor) control system, the motor control system is a dual closed-loop control system with a current loop and a speed loop; when the motor is stationary before starting, a preset voltage signal (such as injecting a square wave voltage signal V) is injected into the d-axis voltage of the speed loop. inj After that, the three-phase current of the motor is detected, and the position of the motor rotor is calculated as the initial position of the motor rotor; after obtaining the initial position of the motor rotor, while the motor is still stationary (i.e., the motor is at zero speed), the target value of the d-axis current i of the current loop is set. dref =The given current i during the motor starting phase dstart (i dstart >0), given the reference speed n of the motor rotor ref The position observation algorithm uses a flux linkage observer to control the motor in a closed-loop operation. During the closed-loop operation of the motor, the motor speed n observed by the flux linkage observer is obtained. e The motor speed n observed by the flux linkage observer e Greater than or equal to the preset speed threshold n th In this case, let the target value of the d-axis current of the current loop be i. dref =0, in the preset speed transition zone [minimum speed ω]th Maximum speed ω high Within, the observed electric angular velocity ω is determined by the magnetic flux observer algorithm. magnetic The observed electric angular velocity ω of the sliding mode observation algorithm sliding The estimated motor speed ω is obtained by weighted average calculation. e The position observation algorithm employs the sliding diaphragm observer algorithm, based on the estimated motor speed ω. e The motor speed n is obtained through speed calculation. e This participates in the calculation of the speed loop, enabling efficient sensorless control of the permanent magnet synchronous motor across its entire speed range. Thus, by detecting the initial rotor position of the motor (such as a permanent magnet synchronous motor) through the injection of a voltage vector (such as a square wave voltage vector) when the motor (such as a permanent magnet synchronous motor) starts and when the motor is stationary, the d-axis current i is set at zero speed. d To achieve a positive value, a flux linkage observer algorithm and a sliding mode observer algorithm are used as observation algorithms for different speed ranges, and a speed transition zone is set to realize efficient sensorless control of the motor (such as a permanent magnet synchronous motor) across the entire speed range. This avoids mechanical reversal during motor startup and improves motor reliability. This motor controller relates to the manufacturing of power electronic components.

[0174] According to an embodiment of the present invention, a motor control device corresponding to the motor control method is also provided. See also Figure 6 The diagram shows a structural schematic of an embodiment of the device of the present invention. This motor controller relates to the manufacture of power electronic components. The motor control device includes a current loop and a speed loop, and the motor is, for example, a permanent magnet synchronous motor. The speed observation algorithm in the motor control system includes a preset flux linkage observer algorithm and a preset sliding film observer algorithm. The motor has a rotor and a stator, and the stator has three-phase windings. In the solution of the present invention, as shown... Figure 6 As shown, the control device for the motor includes: an acquisition unit and a control unit.

[0175] The control unit is configured to inject a preset voltage signal into the d-axis voltage of the speed loop before the motor starts, when the motor needs to be started, so as to generate the three-phase current of the motor in the three-phase windings; wherein the preset voltage signal is, for example, a square wave voltage signal V. inj For the specific functions and processing of this control unit, please refer to step S110.

[0176] The acquisition unit is configured to acquire the initial position of the rotor in the motor. The specific functions and processing of this acquisition unit are described in step S120.

[0177] The control unit is further configured to set the d-axis target current of the current loop, set the target speed of the motor, and set the position observation algorithm of the speed loop based on the initial position of the rotor in the motor, thereby controlling the motor to start and run in a zero-speed closed loop; wherein, the d-axis target current of the current loop is such as the d-axis current target value i. dref The target speed of the motor is as given by the reference speed n. ref The position observation algorithm of the speed loop is used to observe and obtain the estimated speed ω of the motor. e Then, based on the estimated speed ω of the motor e The rotational speed n of the motor can be calculated. e For details on the specific functions and processing of this control unit, please refer to step S130.

[0178] The acquisition unit is further configured to acquire the rotational speed of the motor; the rotational speed of the motor, such as the estimated rotational speed ω of the motor observed by the flux linkage observer. e The calculated motor speed n e For details on the specific functions and processing of this acquisition unit, please refer to step S140.

[0179] The control unit is further configured to switch the d-axis target current of the current loop and switch the position observation algorithm of the speed loop according to the rotational speed of the motor, and continue to control the closed-loop operation of the motor. The specific functions and processing of this control unit are further described in step S150.

[0180] In the present invention, the control system of the motor has a current loop and a speed loop, and the motor is such as a permanent magnet synchronous motor. When the motor needs to be started, before the motor starts, a preset voltage signal is injected into the d-axis voltage of the speed loop to generate the three-phase current of the motor in the three-phase windings; the initial position of the rotor in the motor is obtained; based on the initial position of the rotor in the motor, the target current of the d-axis of the current loop is set, the target speed of the motor is set, and the position observation algorithm of the speed loop is set to control the motor to start and run in a zero-speed closed loop; the speed of the motor is obtained; according to the speed of the motor, the target current of the d-axis of the current loop is switched, and the position observation algorithm of the speed loop is switched to continue to control the closed-loop operation of the motor. Thus, by controlling the motor to start in a zero-speed closed loop when the motor (such as a permanent magnet synchronous motor) starts, such as detecting the initial position of the motor rotor by injecting a voltage vector (such as a square wave voltage vector) when the motor is stationary, and setting the d-axis current i when the motor is at zero speed. dThe value is positive; and the observation algorithm is smoothly switched during the process of the motor from standstill to speed-up. For example, different observation algorithms (such as flux linkage observer algorithm and sliding mode observation algorithm) are used as observation algorithms for different speed ranges and speed transition zones are set to achieve efficient sensorless control of the motor (such as permanent magnet synchronous motor) across the entire speed range, avoid mechanical reversal when the motor starts, and improve motor reliability.

[0181] Since the processing and functions implemented by the device in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in the description of this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0182] According to an embodiment of the present invention, a motor controller corresponding to a control device for a motor is also provided. This motor controller may include the motor control device described above. This motor controller relates to the manufacture of power electronic components.

[0183] Since the processing and functions implemented by the motor controller in this embodiment are basically the same as those in the embodiments, principles and examples of the aforementioned device, any details not covered in this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0184] According to an embodiment of the present invention, a motor corresponding to a control device for a motor is also provided. The motor may include: the motor control device described above, or the motor controller described above. The motor controller relates to the manufacture of power electronic components.

[0185] Since the processing and functions implemented by the motor in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned device, any details not covered in this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0186] According to an embodiment of the present invention, a computer program product corresponding to the motor control method is also provided, including a computer program that, when executed by a processor, implements the steps of the motor control method described above.

[0187] Since the processing and functions implemented by the product in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in the description of this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0188] According to an embodiment of the present invention, a storage medium corresponding to a motor control method is also provided, the storage medium including a stored program, wherein, when the program is executed, the device where the storage medium is located executes the steps of the motor control method described above.

[0189] Since the processing and functions implemented by the storage medium in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0190] In summary, it is readily understood by those skilled in the art that, without conflict, the aforementioned advantageous methods can be freely combined and superimposed.

[0191] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A method for controlling an electric motor, characterized in that, The control system of the motor has a current loop and a speed loop; the control method of the motor includes: Before the motor starts, a preset voltage signal is injected into the d-axis voltage of the speed ring; Obtain the initial position of the rotor in the motor; Based on the initial position of the rotor in the motor, the target current of the current loop on the d-axis is set, the target speed of the motor is set, and the position observation algorithm of the speed loop is set to control the motor to start and run at zero speed in a closed loop. Obtain the rotational speed of the motor; Based on the motor's rotational speed, the target current of the d-axis of the current loop is switched, and the position observation algorithm of the rotational speed loop is switched to continue controlling the motor's closed-loop operation.

2. The motor control method according to claim 1, characterized in that, Preset voltage signals, including: square wave voltage signal V inj ; Injecting a preset voltage signal into the d-axis voltage of the rotational speed ring includes: With the motor stationary, a square wave voltage signal V is injected into the d-axis voltage of the speed loop. inj This is to generate the three-phase current of the motor at the three-phase windings of the motor.

3. The motor control method according to claim 1, characterized in that, Obtaining the initial position of the rotor in the motor includes: The three-phase current of the motor is obtained based on the preset voltage signal injected into the d-axis voltage of the speed loop; Based on the three-phase current of the motor, the rotational speed and angle of the rotor in the motor are determined through the current loop, which serves as the initial position of the rotor in the motor.

4. The motor control method according to claim 1, characterized in that, The position observation algorithm of the rotational speed ring includes: a preset first observation algorithm; Based on the initial position of the rotor in the motor, the target current of the current loop on the d-axis is set, the target speed of the motor is set, and the position observation algorithm of the speed loop is set to control the zero-speed closed-loop start-up and operation of the motor, including: The target current of the d-axis of the current loop is set to a positive value, the target speed of the motor is given in the speed loop, and the position observation algorithm of the speed loop is set to adopt a preset first observation algorithm. Based on the initial position of the rotor in the motor, the motor is controlled to start at zero speed in a closed loop when the motor speed is zero.

5. The motor control method according to claim 4, characterized in that, Setting the d-axis target current of the current loop to a positive value includes: Set the d-axis target current i of the current loop. dref A starting current i is given to the d-axis of the motor. dstart And the starting current i of the d-axis of the motor dstart >0.

6. The motor control method according to claim 5, characterized in that, Setting the d-axis target current of the current loop to a positive value also includes: The starting current i of the motor's d-axis is calculated using the following formula. dstart : Among them, i dstart =k1*i rated ; k1 is a preset calculation coefficient, and 0 < k1 < 1; i rated The rated current of the motor is given.

7. The motor control method according to any one of claims 1 to 6, characterized in that, Based on the motor's rotational speed, the target current of the current loop on the d-axis is switched, and the position observation algorithm of the rotational speed loop is switched to continue controlling the motor's closed-loop operation, including: Determine whether the motor speed is greater than or equal to a preset first speed threshold. If it is determined that the motor speed is greater than or equal to a preset speed threshold, the d-axis target current of the current loop is switched, and the position observation algorithm of the speed loop is switched to continue controlling the closed-loop operation of the motor.

8. The motor control method according to claim 7, characterized in that, Switching the d-axis target current of the current loop and switching the position observation algorithm of the speed loop to continue controlling the closed-loop operation of the motor includes: The target d-axis current of the current loop is switched from being positive to being zero, and the position observation algorithm of the speed loop is smoothly switched from a preset first observation algorithm to a preset second observation algorithm, so as to continue controlling the closed-loop operation of the motor.

9. The motor control method according to claim 8, characterized in that, The position observation algorithm of the rotational speed ring includes: a preset first observation algorithm and a preset second observation algorithm; Smoothly switching the position observation algorithm of the rotational speed ring from a preset first observation algorithm to a preset second observation algorithm includes: Determine whether the motor speed is less than a preset second speed threshold; wherein the preset second speed threshold is greater than a preset first speed threshold; If it is determined that the motor speed is less than a preset second speed threshold, then the preset first observation algorithm and the preset second observation algorithm are weighted and fused to obtain a fused observation algorithm, which is used as the position observation algorithm of the speed loop. If it is determined that the motor speed is greater than or equal to a preset second speed threshold, then a preset second observation algorithm is used as the position observation algorithm for the speed loop.

10. The motor control method according to claim 9, characterized in that, The first and second preset observation algorithms are weighted and fused to obtain a fused observation algorithm, which includes: Based on the weighted average method, a weighted fusion of the preset first observation algorithm and the preset second observation algorithm is obtained to obtain a fused observation algorithm; using the fused observation algorithm, the fused estimated speed of the motor is calculated according to the following formula: oh e =k2*ω magnetic +(1-k2)*ω sliding ; Where, ω e The fusion estimated speed of the motor is given by k2, which is a preset weighting coefficient and 0 ≤ k2 ≤ 1; ω magnetic To obtain the first estimated speed of the motor using a preset first observation algorithm, ω sliding The second estimated speed of the motor is obtained by using a preset first observation algorithm.

11. The motor control method according to claim 9 or 10, characterized in that, in, The preset first observation algorithm includes: a magnetic flux observer algorithm; the preset second observation algorithm includes: a synovial observer algorithm.

12. A control device for an electric motor, characterized in that, The control system of the motor has a current loop and a speed loop; the control device of the motor includes: The control unit is configured to inject a preset voltage signal into the d-axis voltage of the speed ring before the motor starts; The acquisition unit is configured to acquire the initial position of the rotor in the motor; The control unit is also configured to set the d-axis target current of the current loop, set the target speed of the motor, and set the position observation algorithm of the speed loop based on the initial position of the rotor in the motor, and control the motor to start and run in a zero-speed closed loop. The acquisition unit is further configured to acquire the rotational speed of the motor; The control unit is also configured to switch the d-axis target current of the current loop according to the rotational speed of the motor, and switch the position observation algorithm of the rotational speed loop to continue controlling the closed-loop operation of the motor.

13. A motor controller, characterized in that, include: The motor control device as described in claim 12.

14. An electric motor, characterized in that, include: The motor control device as described in claim 12, or the motor controller as described in claim 13.

15. A storage medium, characterized in that, The storage medium includes a stored program, wherein, when the program is executed, the device containing the storage medium is controlled to perform the motor control method according to any one of claims 1 to 11.

16. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the motor control method according to any one of claims 1 to 11.

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