Speed tracking method and device based on zero current control

Abstract

The application discloses a kind of zero current control-based rotational speed tracking method and device, it is related to motor control technical field.Under the condition of zero current control to permanent magnet synchronous motor, call PR regulator to obtain the initial stator voltage value of permanent magnet synchronous motor;According to the value range of virtual resistance, the initial stator voltage value is updated to obtain the target stator voltage value;When target stator voltage value meets preset condition, the rotational speed and position angle of permanent magnet synchronous motor are determined according to target stator voltage value.By using PR regulator, the problem that PI regulator converges slowly for AC signal is overcome, so that the motor speed is quickly estimated;The way of introducing virtual resistance makes the motor current in a controllable state, so that the motor generates smaller braking torque, solves the problem of dc side bus voltage overvoltage.By accurately estimating motor speed and direction, the frequency converter is smoothly transitioned from speed tracking state without current impact to normal operating state.

Description

Technical Field

[0001] This invention relates to the field of motor control technology, and in particular to a speed tracking method and apparatus based on zero-current control. Background Technology

[0002] During the re-energization process of a permanent magnet synchronous motor, the motor will generate an unloaded back electromotive force due to the presence of permanent magnets. In order to ensure that there is no current surge at the re-energization time, the inverter output needs to be consistent with the amplitude and phase of the unloaded back electromotive force.

[0003] In the current inverter speed tracking process, under zero-current control, the current loop setpoint and angle setpoint are both zero, resulting in an AC quantity. The current closed-loop proportional-integral (PI) regulator is slow in regulating this AC quantity. The back electromotive force of the permanent magnet synchronous motor is the only voltage source in the control loop, causing energy to flow from the motor side to the inverter side. This puts the motor in a braking state, leading to a large stator current and high braking torque, causing a surge in bus voltage and potentially resulting in a bus overvoltage fault. Furthermore, the feedback current in the two-phase stationary coordinate system is sinusoidal; the slow regulation of this AC quantity by the current closed-loop PI regulator leads to stator current overcurrent faults.

[0004] Therefore, how to overcome the problems of slow AC convergence, stator current overcurrent, and DC bus voltage overvoltage urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a speed tracking method and device based on zero-current control to solve the technical problems of slow AC convergence, stator current overcurrent, and DC bus voltage overvoltage in current frequency converter speed tracking.

[0006] To solve the above-mentioned technical problems, the present invention provides a speed tracking method based on zero-current control, comprising:

[0007] When performing zero-current control on a permanent magnet synchronous motor, the initial stator voltage value of the permanent magnet synchronous motor is obtained by calling the PR regulator.

[0008] Obtain the value range of the virtual resistor, update the initial stator voltage value according to the value range of the virtual resistor, and obtain the target stator voltage value;

[0009] When the target stator voltage value meets the preset conditions, the rotational speed and position angle of the permanent magnet synchronous motor are determined based on the target stator voltage value.

[0010] The speed and position angle of the permanent magnet synchronous motor are used as the initial values ​​for vector control to achieve speed tracking of the permanent magnet synchronous motor.

[0011] Preferably, the step of calling the PR regulator to obtain the initial stator voltage value of the permanent magnet synchronous motor includes:

[0012] In the zero-current control of the permanent magnet synchronous motor, the first axis current and the second axis current corresponding to the two-phase stationary coordinate system are obtained;

[0013] Closed-loop control is performed on the first shaft current and the second shaft current to obtain current feedback values, wherein the reference value of the first shaft current is given as 0, and the reference value of the second shaft current is given as 0.

[0014] The PR regulator is invoked, and the initial stator voltage value of the permanent magnet synchronous motor is obtained based on the current feedback value.

[0015] Preferably, the current feedback value includes a first current feedback value corresponding to the first shaft current and a second current feedback value corresponding to the second shaft current. The step of calling the PR regulator and obtaining the initial stator voltage value of the permanent magnet synchronous motor based on the current feedback value includes:

[0016] Invoke the PR regulator to obtain the adjustment formula of the PR regulator;

[0017] The first axis component of the initial stator voltage value is determined based on the adjustment formula, the first current feedback value, and the reference value of the first axis current.

[0018] The second axis component of the initial stator voltage value is determined based on the adjustment formula, the second current feedback value, and the reference value of the second axis current.

[0019] Preferably, updating the initial stator voltage value according to the range of the virtual resistance to obtain the target stator voltage value includes:

[0020] The amplitude range of the stator current of the permanent magnet synchronous motor is determined based on the virtual resistance.

[0021] Obtain the amplitude reference value and amplitude feedback value of the stator current;

[0022] The maximum virtual resistance value is determined based on the range of values ​​for the virtual resistance.

[0023] The current virtual resistance value is determined based on the maximum virtual resistance value, the stator current amplitude reference value, and the amplitude feedback value.

[0024] The target stator voltage value is determined based on the current virtual resistance value, the amplitude feedback value of the stator current, and the initial stator voltage value.

[0025] Preferably, determining the target stator voltage value based on the current virtual resistance value, the stator current amplitude feedback value, and the initial stator voltage value includes:

[0026] The amplitude feedback value of the stator current is multiplied by the current virtual resistance value to determine the first voltage component value;

[0027] The first axis component of the target stator voltage value is determined by performing difference processing between the first axis component of the initial stator voltage value and the first voltage component value.

[0028] The second axis component of the initial stator voltage value is determined by performing difference processing between the second axis component of the initial stator voltage value and the first voltage component value.

[0029] Preferably, determining the rotational speed and position angle of the permanent magnet synchronous motor based on the target stator voltage value includes:

[0030] The phase of the back electromotive force of the permanent magnet synchronous motor is determined by performing arctangent processing on the first axis component and the second axis component of the target stator voltage value.

[0031] The rotational speed of the permanent magnet synchronous motor is determined based on the phase of its back electromotive force.

[0032] Obtain the rotor flux linkage amplitude of the permanent magnet synchronous motor;

[0033] The back electromotive force amplitude of the permanent magnet synchronous motor is determined based on the rotational speed of the permanent magnet synchronous motor and the rotor flux linkage amplitude.

[0034] The position angle is determined based on the direction of rotation of the permanent magnet synchronous motor, the rotational speed, and the sampling frequency.

[0035] Preferably, the preset condition is that the amplitude feedback value of the stator current is less than a preset multiple of the rated current of the permanent magnet synchronous motor.

[0036] Preferably, the process of determining the value range of the virtual resistor includes:

[0037] Obtain the sampling frequency, direct-axis inductance, and quadrature-axis inductance of the permanent magnet synchronous motor;

[0038] The minimum value between the direct-axis inductance and the quadrature-axis inductance is selected as the stator inductance of the permanent magnet synchronous motor;

[0039] The critical value within the range of values ​​is determined based on the stator inductance of the permanent magnet synchronous motor and the sampling frequency.

[0040] Preferably, before determining the speed and position angle of the permanent magnet synchronous motor based on the target stator voltage value, the method further includes:

[0041] When the target stator voltage value meets the preset condition, the operating time of the permanent magnet synchronous motor after the target stator voltage value is determined is obtained;

[0042] When the operating time reaches the preset operating time, the process proceeds to the step of determining the speed and position angle of the permanent magnet synchronous motor based on the target stator voltage value.

[0043] To solve the above-mentioned technical problems, the present invention provides a speed tracking device based on zero-current control, comprising:

[0044] The module is used to call the PR regulator to obtain the initial stator voltage value of the permanent magnet synchronous motor in the case of zero-current control of the permanent magnet synchronous motor.

[0045] The first determining module is used to obtain the value range of the virtual resistor, update the initial stator voltage value according to the value range of the virtual resistor, and obtain the target stator voltage value.

[0046] The second determining module is used to determine the speed and position angle of the permanent magnet synchronous motor based on the target stator voltage value when the target stator voltage value meets the preset conditions.

[0047] The speed and position angle of the permanent magnet synchronous motor are used as the initial values ​​for vector control to achieve speed tracking of the permanent magnet synchronous motor.

[0048] This invention provides a speed tracking method based on zero-current control, comprising: when performing zero-current control on a permanent magnet synchronous motor (PMSM), calling a PR regulator to obtain the initial stator voltage value of the PMSM; obtaining the value range of a virtual resistor, updating the initial stator voltage value according to the virtual resistor value range to obtain a target stator voltage value; when the target stator voltage value meets preset conditions, determining the speed and position angle of the PMSM based on the target stator voltage value, and using the speed and position angle as the initial values ​​for vector control to achieve speed tracking of the PMSM. This invention overcomes the slow convergence problem of PI regulators for AC signals by employing a PR regulator, enabling it to quickly estimate the motor speed; simultaneously, by introducing a virtual resistor, the motor current is kept under control, thereby generating a smaller braking torque to solve the problem of DC bus voltage overvoltage. Furthermore, through accurate estimation of the motor speed and direction, the inverter smoothly transitions from speed tracking state to normal operation state without current impact, thus solving the problem of stator current overcurrent.

[0049] In addition, the present invention also provides a speed tracking device based on zero current control, which has the same beneficial effects as the speed tracking method based on zero current control described above. Attached Figure Description

[0050] To more clearly illustrate the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0051] Figure 1 A flowchart illustrating a speed tracking method based on zero-current control, provided as an embodiment of the present invention;

[0052] Figure 2 An equivalent circuit diagram with virtual resistance is provided for an embodiment of the present invention;

[0053] Figure 3 A flowchart of another speed tracking method based on zero-current control provided in an embodiment of the present invention;

[0054] Figure 4 A schematic diagram of a speed tracking method based on zero-current control provided for an embodiment of the present invention;

[0055] Figure 5 This is a structural diagram of a speed tracking device based on zero-current control, provided in an embodiment of the present invention. Detailed Implementation

[0056] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present invention.

[0057] The core of this invention is to provide a speed tracking method and device based on zero-current control, so as to solve the technical problems of slow AC convergence, stator current overcurrent and DC bus voltage overvoltage in current frequency converter speed tracking.

[0058] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0059] To quickly start a rotating motor, it's necessary to obtain the motor's current speed, enabling the frequency converter to perform speed tracking in many situations. In current speed tracking schemes, the feedback current in a two-phase stationary coordinate system is sinusoidal. However, using a current closed-loop PI regulator to adjust the AC quantity results in a slow adjustment process, potentially leading to stator current overcurrent faults. With both the current loop and angle setpoints at zero, the back electromotive force of the permanent magnet synchronous motor becomes the only voltage source in the control loop. Energy flows from the motor side to the inverter side, putting the motor in a braking state. The large stator current generates high braking torque, causing a surge in bus voltage and resulting in bus overvoltage faults. The speed tracking method based on zero-current control provided by this invention solves the above-mentioned technical problems.

[0060] Figure 1 A flowchart of a speed tracking method based on zero-current control provided for an embodiment of the present invention is shown below. Figure 1 As shown, the method includes:

[0061] S11: When performing zero-current control on a permanent magnet synchronous motor, call the PR regulator to obtain the initial stator voltage value of the permanent magnet synchronous motor.

[0062] S12: Obtain the value range of the virtual resistor, update the initial stator voltage value according to the value range of the virtual resistor, and obtain the target stator voltage value;

[0063] S13: If the target stator voltage value meets the preset conditions, determine the speed and position angle of the permanent magnet synchronous motor based on the target stator voltage value;

[0064] The speed and position angle of the permanent magnet synchronous motor are used as the initial values ​​for vector control to achieve speed tracking of the permanent magnet synchronous motor.

[0065] Specifically, zero-current control is performed on the permanent magnet synchronous motor (PMSM) using a dual-current closed-loop control system, injecting zero current into the freely rotating PMSM. A proportional resonant (PR) regulator is used to obtain the initial stator voltage value of the PMSM. In this embodiment, considering that the feedback current is an AC quantity, and based on the mathematical model of the PMSM in the synchronous rotating coordinate system, both the d-axis and q-axis currents are DC quantities. Therefore, a PI regulator is generally sufficient to achieve error-free regulation of the dq-axis current. However, due to the limited bandwidth of the PI regulator, it cannot effectively track AC signals, meaning it cannot achieve error-free regulation of AC signals. The PR regulator, on the other hand, can achieve error-free control of AC quantities; therefore, this embodiment uses a PR regulator to obtain the stator voltage value.

[0066] In some embodiments, calling the PR regulator to obtain the initial stator voltage value of the permanent magnet synchronous motor includes:

[0067] In zero-current control of a permanent magnet synchronous motor, the first axis current and the second axis current corresponding to the two-phase stationary coordinate system are obtained.

[0068] Closed-loop control is performed on the first-axis current and the second-axis current to obtain current feedback values, wherein the reference value of the first-axis current is given as 0, and the reference value of the second-axis current is given as 0.

[0069] The PR regulator is invoked, and the initial stator voltage value of the permanent magnet synchronous motor is obtained based on the current feedback value.

[0070] Specifically, zero current is injected into the freely rotating permanent magnet synchronous motor under dual-current closed-loop control. Simultaneously, closed-loop control is performed based on the currents of the first axis α and the second axis β in a two-phase stationary coordinate system. The reference value for the current of the first axis α (first axis current) is given as 0, i.e. Additionally, the reference value for the first-axis current is the same as the reference value for the excitation current. The reference value for the second-axis (β-axis) current (second-axis current) is given as 0, i.e.

[0071] The output motor terminal voltage, i.e., the initial stator voltage value, is adjusted using a PR regulator. Based on the current regulation of the PR regulator, the current components of the first axis α and the second axis β in a two-phase stationary coordinate system are tracked without steady-state error to obtain the first axis component of the initial stator voltage value. Second axis component In this embodiment, the adjustment process of the corresponding regulator is not limited. It can be adjusted according to the existing regulator or a new adjustment method can be used.

[0072] In some embodiments, the current feedback value includes a first current feedback value corresponding to the first axis current and a second current feedback value corresponding to the second axis current. The PR regulator is invoked, and based on the current feedback value, the initial stator voltage value of the permanent magnet synchronous motor is obtained, including:

[0073] Call the PR regulator to obtain the PR regulator's adjustment formula;

[0074] The first axis component of the initial stator voltage value is determined based on the adjustment formula, the first current feedback value, and the reference value of the first axis current.

[0075] The second axis component of the initial stator voltage value is determined based on the adjustment formula, the second current feedback value, and the reference value of the second axis current.

[0076] Specifically, the adjustment formula, or equation, for the PR regulator is:

[0077]

[0078] Among them, K p For proportional gain, K i For the integral gain, ω c ω0 is the cutoff frequency of the resonant controller, ω0 is the resonant frequency, and s is the Laplace operator.

[0079] The current feedback value includes the first current feedback value i corresponding to the first axis current in the two-phase stationary coordinate system. αf The second current feedback value i corresponding to the second axis current βf The formulas for the first and second axis components are as follows:

[0080]

[0081] Among them, K p For proportional gain, K i For the integral gain, ω c Let ω0 be the cutoff frequency of the resonant controller, ω0 be the resonant frequency, and s be the Laplace operator. For the first axis component, For the second axis component, For the first axis current, For the second-axis current, i αf i is the first current feedback value. βf This is the second current feedback value.

[0082] In step S12, the range of values ​​for the virtual resistance is obtained. During the belt-speed reconnection process, since the rotor position angle is unknown, coordinate transformation of the three-phase sampling current and command voltage cannot be achieved. To prevent current surges and bus voltage rises, a virtual resistance R is added in the two-phase stationary coordinate system. v The target stator voltage value is updated by dynamically adjusting the current in the equivalent circuit of the permanent magnet synchronous motor through virtual resistance. Specifically, the voltage component of the back electromotive force of the permanent magnet synchronous motor is adjusted to reduce the braking torque of the motor.

[0083] Figure 2 An equivalent circuit diagram with virtual resistance is provided for an embodiment of the present invention, such as... Figure 2 As shown, the virtual resistance R v When connected in series with a permanent magnet synchronous motor, the permanent magnet synchronous motor is equivalent to the L and R in the equivalent circuit. s respectively with e α e β The resulting series circuit.

[0084] When the target stator voltage value meets preset conditions, the speed and position angle of the permanent magnet synchronous motor can be determined based on the target stator voltage value. That is, after regulation by the dual closed-loop current, the back electromotive force of the permanent magnet synchronous motor serves as the sole voltage source in the control loop. The amplitude and phase of the target stator voltage value and the back electromotive force are equal, and the position angle and speed can be determined based on the motor's direction of rotation. It should be noted that the preset conditions in this embodiment are not limited and can be set according to actual conditions. These conditions could include meeting a certain threshold or maintaining the target stator voltage value for a period of time until it stabilizes.

[0085] After the inverter blocks the pulse, the current speed, back EMF amplitude and rotor position angle of the permanent magnet synchronous motor are obtained and used as the initial values ​​for vector control to achieve speed tracking of the permanent magnet synchronous motor.

[0086] This invention provides a speed tracking method based on zero-current control, comprising: when performing zero-current control on a permanent magnet synchronous motor (PMSM), calling a PR regulator to obtain the initial stator voltage value of the PMSM; obtaining the value range of a virtual resistor, updating the initial stator voltage value according to the value range of the virtual resistor to obtain a target stator voltage value; when the target stator voltage value meets preset conditions, determining the speed and position angle of the PMSM based on the target stator voltage value, and using the speed and position angle as the initial values ​​for vector control to achieve speed tracking of the PMSM. This invention overcomes the slow convergence problem of the PI regulator for AC signals by employing a PR regulator, enabling it to quickly estimate the motor speed; simultaneously, by introducing a virtual resistor, the motor current is kept under control, thereby generating a smaller braking torque to solve the problem of DC bus voltage overvoltage. Furthermore, through accurate estimation of the motor speed and direction, the inverter smoothly transitions from speed tracking state to normal operation state without current impact, thus solving the stator current overcurrent fault.

[0087] In some embodiments, the process of determining the value range of the virtual resistor in step S12 includes:

[0088] Obtain the sampling frequency, direct-axis inductance, and quadrature-axis inductance of the permanent magnet synchronous motor;

[0089] Choose the minimum value between the direct-axis inductance and the quadrature-axis inductance as the stator inductance of the permanent magnet synchronous motor;

[0090] Based on the stator inductance and sampling frequency of the permanent magnet synchronous motor, the critical value within the range is determined.

[0091] Specifically, the range of values ​​is:

[0092] Where, L=min{L d ,Lq} represents the stator inductance, L d L is the direct-axis inductance of a permanent magnet synchronous motor. q T is the quadrature axis inductance of a permanent magnet synchronous motor. s The sampling frequency.

[0093] Here, the critical values ​​of the range include a first critical value and a second critical value. The first critical value is... The second critical value is 0, which means that the first critical value is greater than the second critical value.

[0094] This allows us to determine the virtual resistance R. v The range of values ​​for .

[0095] In this embodiment, the range of virtual resistance values ​​is determined by the direct-axis inductance and quadrature-axis inductance of the permanent magnet synchronous motor and the sampling rate, making the virtual resistance values ​​reasonable and improving the accuracy of adjustment.

[0096] In some embodiments, updating the initial stator voltage value according to the range of virtual resistance values ​​in step S12 to obtain the target stator voltage value includes:

[0097] The amplitude range of the stator current of the permanent magnet synchronous motor is determined based on the virtual resistance.

[0098] Obtain the reference value and feedback value of the stator current amplitude;

[0099] The maximum virtual resistance value is determined based on the range of virtual resistance values.

[0100] The current virtual resistance value is determined based on the maximum virtual resistance value, the stator current amplitude reference value, and the amplitude feedback value.

[0101] The target stator voltage value is determined based on the current virtual resistance value, the amplitude feedback value of the stator current, and the initial stator voltage value.

[0102] Specifically, the amplitude range of the stator current of the permanent magnet synchronous motor is determined based on the virtual resistance, using the following formula:

[0103]

[0104] Among them, E m R is the maximum amplitude of the back electromotive force. vm I is the maximum virtual resistance value. s R is the amplitude of the stator current. s This is the stator resistance value of the permanent magnet synchronous motor.

[0105] Obtain the reference value I of stator current amplitude. sref and amplitude feedback value I sfed Dynamically adjust the resistance value R of the virtual resistor.v This adjusts the initial stator voltage values ​​corresponding to the α-axis and β-axis components of the back electromotive force of the permanent magnet synchronous motor, thereby reducing the braking torque of the motor.

[0106] The current virtual resistance value is determined based on the maximum virtual resistance value, the stator current amplitude reference value, and the amplitude feedback value. The specific formula is as follows:

[0107]

[0108] Among them, R vm K is the maximum virtual resistance value. p For proportional gain, K i Let be the integral gain, s be the Laplace operator, and I be the integral gain. sref I is the reference value for the amplitude of the stator current. sfed This refers to the amplitude feedback value of the stator current. I α I is the first axis current component of the stator current amplitude feedback value. β The second-axis current component is the amplitude feedback value of the stator current.

[0109] Determining the target stator voltage value based on the current virtual resistance value, the stator current amplitude feedback value, and the initial stator voltage value, in some embodiments specifically includes:

[0110] The first voltage component value is determined by multiplying the amplitude feedback value of the stator current with the current virtual resistance value.

[0111] The first axis component of the initial stator voltage value is determined by performing difference processing on the first voltage component value and the first axis component value.

[0112] The second axis component of the initial stator voltage value is determined by performing difference processing between the second axis component and the first voltage component value.

[0113] The specific formula is as follows:

[0114]

[0115] Among them, I sref I is the reference value for the amplitude of the stator current. sfed This is the amplitude feedback value of the stator current. For the first axis component, For the second axis component, u α The first axis component after adjustment, i.e., the first axis component of the target stator voltage value, u β R is the adjusted second-axis component, i.e., the second-axis component of the target stator voltage value. v This is a virtual resistor.

[0116] The embodiment provides a dynamically adjustable virtual resistor to reduce the braking torque of the motor, thereby solving the problem of DC bus voltage overvoltage.

[0117] Based on the above embodiments, in some embodiments, the rotational speed and position angle of the permanent magnet synchronous motor are determined according to the target stator voltage value, including:

[0118] The phase of the back electromotive force of the permanent magnet synchronous motor is determined by performing arctangent processing on the first axis component and the second axis component of the target stator voltage value.

[0119] The speed of the permanent magnet synchronous motor is determined based on the phase of its back electromotive force.

[0120] Obtain the rotor flux linkage amplitude of a permanent magnet synchronous motor;

[0121] The back electromotive force amplitude of the permanent magnet synchronous motor is determined based on its rotational speed and rotor flux linkage amplitude.

[0122] The position angle is determined based on the direction of rotation, speed, and sampling frequency of the permanent magnet synchronous motor.

[0123] Specifically, since the target stator voltage and the back electromotive force have equal amplitude and phase, the formula for the phase of the back electromotive force is as follows:

[0124]

[0125] Among them, u α u is the first axis component of the target stator voltage value. β θ is the second axis component of the target stator voltage value. e This represents the phase of the back electromotive force.

[0126] The process for determining the speed of a permanent magnet synchronous motor is illustrated by the following formula:

[0127]

[0128] Where, θ e ω is the phase of the back electromotive force. r This refers to the rotational speed of the permanent magnet synchronous motor.

[0129] The process for determining the back electromotive force amplitude of a permanent magnet synchronous motor is illustrated by the following formula:

[0130] u m =ω r *ψ f ;

[0131] Where, ψ f ω represents the rotor flux linkage amplitude of the permanent magnet synchronous motor. r This refers to the rotational speed of the permanent magnet synchronous motor.

[0132] The process for determining the position angle is illustrated by the following formula:

[0133]

[0134] Where, θ e ω is the phase of the back electromotive force. r T is the rotational speed of the permanent magnet synchronous motor. s The sampling frequency.

[0135] In some embodiments, the preset condition is that the amplitude feedback value of the stator current is less than a preset multiple of the rated current of the permanent magnet synchronous motor.

[0136] The preset conditions in this embodiment are designed to facilitate the subsequent output of the speed and position angle of the permanent magnet synchronous motor. If the preset conditions are met, the output is performed; otherwise, the resistance value of the virtual resistor is adjusted.

[0137] In some embodiments, it also includes:

[0138] If the target stator voltage value does not meet the preset conditions, return to the step of updating the initial stator voltage value according to the range of virtual resistance values ​​to obtain the target stator voltage value, until the target stator voltage value meets the preset conditions.

[0139] Based on the above embodiments, before determining the speed and position angle of the permanent magnet synchronous motor according to the target stator voltage value, the method further includes:

[0140] When the target stator voltage value meets the preset conditions, obtain the running time of the permanent magnet synchronous motor after the target stator voltage value is determined;

[0141] When the operating time reaches the preset operating time, the process proceeds to the step of determining the speed and position angle of the permanent magnet synchronous motor based on the target stator voltage value.

[0142] To improve the stability of output speed and position angle, a certain preset operating time is required after the target stator voltage value meets the preset conditions before the output speed and position angle can be stabilized.

[0143] Figure 3 A flowchart of another speed tracking method based on zero-current control provided in an embodiment of the present invention is shown below. Figure 3 As shown, the method includes:

[0144] S21: Inject zero current into the permanent magnet synchronous motor in a free-rotating state;

[0145] S22: PR regulator control;

[0146] S23: Obtain the first and second axis components of the initial stator voltage value;

[0147] S24: Obtain the first axis component and the second axis component of the target stator voltage value;

[0148] S25: Judgment If yes, proceed to step S26; otherwise, return to step S24 to continue adjustment.

[0149] S26: Determine whether the waiting time is greater than the preset time. If yes, proceed to step S27; otherwise, return to step S26 and continue waiting.

[0150] S27: Obtain the speed and position of the permanent magnet synchronous motor.

[0151] In step S25, I rate This is the rated current of the permanent magnet synchronous motor, and 10 is a preset multiple.

[0152] Figure 4 A schematic diagram of speed tracking based on zero-current control is provided as an embodiment of the present invention, as shown below. Figure 4 As shown, the permanent magnet synchronous motor (PMSM) generates three-phase voltages. This embodiment only focuses on the current i in two phases. v and i w The output current i in the two-phase stationary coordinate system α and i β The current reference value of the first axis α (first axis current) and the output current i α The reference value of the second axis β-axis current (second axis current) and the output current i β The superposition of these components, followed by PR adjustment, yields the first axis component of the stator voltage. Second axis component Then through the virtual resistor R v The adjustment yields the first axis component u of the target stator voltage value. α The adjusted second axis component u β Then, the inverter's modulated voltage u is obtained through space vector pulse width modulation (SVPWM). s It passes through the bus voltage v dc , to the permanent magnet synchronous motor.

[0153] For a description of another speed tracking method based on zero current control and a schematic diagram of speed tracking based on zero current control provided in this application, please refer to the above method embodiments. This application will not repeat the description here, as it has the same beneficial effects as the speed tracking method based on zero current control described above.

[0154] The foregoing has described in detail various embodiments of the speed tracking method based on zero-current control. Based on this, the present invention also discloses a speed tracking device based on zero-current control corresponding to the above method. Figure 5 This is a structural diagram of a speed tracking device based on zero-current control, provided in an embodiment of the present invention.

[0155] like Figure 5 As shown, the speed tracking device based on zero-current control includes:

[0156] Module 11 is invoked to call the PR regulator to obtain the initial stator voltage value of the permanent magnet synchronous motor in the case of zero-current control of the permanent magnet synchronous motor.

[0157] The first determining module 12 is used to obtain the value range of the virtual resistor, update the initial stator voltage value according to the value range of the virtual resistor, and obtain the target stator voltage value.

[0158] The second determining module 13 is used to determine the speed and position angle of the permanent magnet synchronous motor based on the target stator voltage value when the target stator voltage value meets the preset conditions.

[0159] The speed and position angle of the permanent magnet synchronous motor are used as the initial values ​​for vector control to achieve speed tracking of the permanent magnet synchronous motor.

[0160] Since the embodiments of the device part correspond to the embodiments described above, please refer to the embodiments described in the method part for the embodiments of the device part, and will not be repeated here.

[0161] For an introduction to the speed tracking device based on zero-current control provided in this application, please refer to the above method embodiments. This application will not repeat the details here, but it has the same beneficial effects as the speed tracking method based on zero-current control described above.

[0162] The foregoing has provided a detailed description of a speed tracking method and apparatus based on zero-current control provided by the present invention. The various embodiments in the specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principle of the invention, and these improvements and modifications also fall within the protection scope of the present invention.

[0163] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A speed tracking method based on zero-current control, characterized in that, include: When performing zero-current control on a permanent magnet synchronous motor, the initial stator voltage value of the permanent magnet synchronous motor is obtained by calling the PR regulator. Obtain the value range of the virtual resistance, obtain the reference value and amplitude feedback value of the stator current; determine the maximum virtual resistance value based on the value range of the virtual resistance; The current virtual resistance value is determined based on the maximum virtual resistance value, the stator current amplitude reference value, and the amplitude feedback value. The target stator voltage value is determined based on the current virtual resistance value, the amplitude feedback value of the stator current, and the initial stator voltage value. When the target stator voltage value meets the preset conditions, the rotational speed and position angle of the permanent magnet synchronous motor are determined based on the target stator voltage value. The speed and position angle of the permanent magnet synchronous motor are used as the initial values ​​for vector control to achieve speed tracking of the permanent magnet synchronous motor.

2. The speed tracking method based on zero-current control according to claim 1, characterized in that, The step of calling the PR regulator to obtain the initial stator voltage value of the permanent magnet synchronous motor includes: In the zero-current control of the permanent magnet synchronous motor, the first axis current and the second axis current corresponding to the two-phase stationary coordinate system are obtained; Closed-loop control is performed on the first shaft current and the second shaft current to obtain current feedback values, wherein the reference value of the first shaft current is given as 0, and the reference value of the second shaft current is given as 0. The PR regulator is invoked, and the initial stator voltage value of the permanent magnet synchronous motor is obtained based on the current feedback value.

3. The speed tracking method based on zero-current control according to claim 2, characterized in that, The current feedback value includes a first current feedback value corresponding to the first shaft current and a second current feedback value corresponding to the second shaft current. The step of calling the PR regulator and obtaining the initial stator voltage value of the permanent magnet synchronous motor based on the current feedback value includes: Invoke the PR regulator to obtain the adjustment formula of the PR regulator; The first axis component of the initial stator voltage value is determined based on the adjustment formula, the first current feedback value, and the reference value of the first axis current. The second axis component of the initial stator voltage value is determined based on the adjustment formula, the second current feedback value, and the reference value of the second axis current.

4. The speed tracking method based on zero-current control according to any one of claims 1 to 3, characterized in that, The amplitude range of the stator current of the permanent magnet synchronous motor is determined based on the virtual resistance.

5. The speed tracking method based on zero-current control according to claim 4, characterized in that, Determining the target stator voltage value based on the current virtual resistance value, the stator current amplitude feedback value, and the initial stator voltage value includes: The amplitude feedback value of the stator current is multiplied by the current virtual resistance value to determine the first voltage component value; The first axis component of the target stator voltage value is determined by performing difference processing between the first axis component of the initial stator voltage value and the first voltage component value. The second axis component of the initial stator voltage value is determined by performing difference processing between the second axis component of the initial stator voltage value and the first voltage component value.

6. The speed tracking method based on zero-current control according to claim 5, characterized in that, The step of determining the speed and position angle of the permanent magnet synchronous motor based on the target stator voltage value includes: The phase of the back electromotive force of the permanent magnet synchronous motor is determined by performing arctangent processing on the first axis component and the second axis component of the target stator voltage value. The rotational speed of the permanent magnet synchronous motor is determined based on the phase of its back electromotive force. Obtain the rotor flux linkage amplitude of the permanent magnet synchronous motor; The back electromotive force amplitude of the permanent magnet synchronous motor is determined based on the rotational speed of the permanent magnet synchronous motor and the rotor flux linkage amplitude. The position angle is determined based on the direction of rotation of the permanent magnet synchronous motor, the rotational speed, and the sampling frequency.

7. The speed tracking method based on zero-current control according to claim 4, characterized in that, The preset condition is that the amplitude feedback value of the stator current is less than a preset multiple of the rated current of the permanent magnet synchronous motor.

8. The speed tracking method based on zero-current control according to any one of claims 1 to 3, characterized in that, The process of determining the value range of the virtual resistor includes: Obtain the sampling frequency, direct-axis inductance, and quadrature-axis inductance of the permanent magnet synchronous motor; The minimum value between the direct-axis inductance and the quadrature-axis inductance is selected as the stator inductance of the permanent magnet synchronous motor; The critical value within the range of values ​​is determined based on the stator inductance of the permanent magnet synchronous motor and the sampling frequency.

9. The speed tracking method based on zero-current control according to claim 1, characterized in that, Before determining the speed and position angle of the permanent magnet synchronous motor based on the target stator voltage value, the method further includes: When the target stator voltage value meets the preset condition, the operating time of the permanent magnet synchronous motor after the target stator voltage value is determined is obtained; When the operating time reaches the preset operating time, the process proceeds to the step of determining the speed and position angle of the permanent magnet synchronous motor based on the target stator voltage value.

10. A speed tracking device based on zero-current control, characterized in that, include: The module is used to call the PR regulator to obtain the initial stator voltage value of the permanent magnet synchronous motor in the case of zero-current control of the permanent magnet synchronous motor. The first determining module is used to obtain the value range of the virtual resistance, obtain the amplitude reference value and amplitude feedback value of the stator current; and determine the maximum virtual resistance value according to the value range of the virtual resistance. The current virtual resistance value is determined based on the maximum virtual resistance value, the stator current amplitude reference value, and the amplitude feedback value. The target stator voltage value is determined based on the current virtual resistance value, the amplitude feedback value of the stator current, and the initial stator voltage value. The second determining module is used to determine the speed and position angle of the permanent magnet synchronous motor based on the target stator voltage value when the target stator voltage value meets the preset conditions. The speed and position angle of the permanent magnet synchronous motor are used as the initial values ​​for vector control to achieve speed tracking of the permanent magnet synchronous motor.

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