A two-phase terminal voltage detection permanent magnet synchronous motor speed re-throw method

Abstract

This invention belongs to the field of motor control and discloses a method for re-energizing a permanent magnet synchronous motor with speed control based on two-phase terminal voltage detection. The method includes: acquiring arbitrary two-phase terminal voltages to reconstruct the line back electromotive force (EMF) and deriving the phase relationship between the line back EMF and the A-phase back EMF; filtering the reconstructed line back EMF and constructing orthogonal signal pairs of the line back EMF; using the orthogonal signal pairs of the line back EMF as input to a phase-locked loop (PLL) to extract the phase and frequency of the line back EMF and obtain the motor's position and speed; if the amplitude of the line back EMF is less than an amplitude threshold, switching to normal start mode; otherwise, if the motor rotates in reverse, switching to reverse speed control re-energizing mode; if the motor rotates forward, switching to forward speed control re-energizing mode. This invention reduces hardware costs and complexity, and decreases the number of analog sampling pins occupied by the microcontroller's ADC. It reduces noise and dependence on current sampling accuracy, enabling rapid and accurate monitoring of the motor's speed and position information.

Description

Technical Field

[0001] This invention belongs to the field of motor control, specifically relating to a method for re-suspension of a permanent magnet synchronous motor with belt speed based on two-phase terminal voltage detection. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) have wide applications in industry, manufacturing, and consumer appliances. Traditional methods using position sensors to obtain the motor rotor position are costly, thus sensorless control technology has attracted considerable attention. Typical sensorless control starting strategies focus on rapid and reliable starting of the motor from a stationary state. However, in high-inertia applications such as fans and pumps, rapid operation from an initial speed is required. Starting directly without estimating position and speed will inevitably cause a large current surge, easily leading to start-up failure. The traditional strategy of braking to zero speed before starting does not meet the requirement of rapid operation, and high-speed braking results in a large phase current surge, increasing the hardware cost of the switching transistors. Therefore, in practical applications, researching a simple, reliable, and low-cost belt-speed re-start method for PMSM sensorless control is of great significance for improving the functionality and reliability of sensorless control systems.

[0003] Existing technologies, such as the patent with publication number CN109379007A, propose a sensorless control method for belt speed re-switching of a permanent magnet synchronous motor, which reconstructs the speed through a three-phase terminal voltage detection circuit. , The back electromotive force of the shaft is used to observe the speed and position of the motor rotor, enabling belt-driven re-switching. However, this method requires a three-channel voltage divider circuit and occupies three microcontroller (MCU) analog-to-digital converter (ADC) sampling pins, increasing hardware costs and reducing controller pin resources.

[0004] Existing technologies, such as the patent with publication number CN113839596A, propose a method for detecting the initial rotor position and speed of a permanent magnet motor. This method uses an optocoupler to detect and output a zero-crossing pulse signal of the line voltage, calculating the motor's rotor position and speed information to achieve belt-speed re-start. However, this method requires zero-crossing detection circuits such as optocouplers, increasing hardware costs.

[0005] Existing technology, such as the patent with publication number WO2023123741A1, proposes a FULL SPEED RANGEFLYING START METHOD FOR HIGH-SPEED PERMANENT MAGNET SYNCHRONOUS MACHINE. This method injects a test short-circuit pulse to collect the stator winding short-circuit current, calculates the initial speed and rotor initial position angle, and achieves belt-speed re-start. However, this short-circuit pulse method introduces noise when the short-circuit current is large at high speeds and depends on the motor parameters and the signal-to-noise ratio of the current sampling, requiring segmented processing. Summary of the Invention

[0006] The purpose of this invention is to provide a method for speed-based re-starting of a permanent magnet synchronous motor based on two-phase terminal voltage detection, reducing hardware costs and complexity, decreasing the number of analog sampling pins required by the microcontroller's ADC, and supporting applications on microcontrollers with small packages and few pins. Simultaneously, it reduces noise and dependence on current sampling accuracy during speed-based re-starting using current detection methods, enabling rapid and accurate monitoring of the motor's speed and position information.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A method for re-energizing a permanent magnet synchronous motor with belt speed based on two-phase terminal voltage detection includes:

[0009] The three phases of the motors are combined in pairs, and the voltage of two phases in any one of the combinations is collected.

[0010] The line back electromotive force is reconstructed based on the collected two-phase terminal voltages, and the phase relationship between the line back electromotive force and the back electromotive force of phase A is derived.

[0011] The reconstructed line back electromotive force is filtered by a cascaded second-order generalized integral orthogonal signal generator combined with a frequency-locked loop, and an orthogonal signal pair of the line back electromotive force is constructed.

[0012] The quadrature signal pair of the line back electromotive force is used as the input of the phase-locked loop to extract the phase and frequency of the line back electromotive force. Combined with the phase relationship between the line back electromotive force and the back electromotive force of A, the position and speed of the motor are obtained.

[0013] If the amplitude of the back electromotive force is less than the amplitude threshold, the system switches to normal start mode; otherwise, if the motor reverses, the system switches to reverse speed re-start mode based on the motor's position and speed; if the motor rotates forward, the system switches to forward speed re-start mode based on the motor's position and speed.

[0014] Several alternative methods are provided below, but they are not intended as additional limitations on the overall solution above. They are merely further additions or optimizations. Provided there are no technical or logical contradictions, each alternative method can be combined individually with respect to the overall solution above, or multiple alternative methods can be combined with each other.

[0015] Preferably, the phase relationship between the linear back electromotive force and the back electromotive force of A is as follows:

[0016] The phase of the line back electromotive force between phase A and phase B leads the phase of the back electromotive force in phase A by 30 degrees.

[0017] The phase of the back electromotive force between phase B and phase C lags behind the phase of the back electromotive force between phase A by 90 degrees.

[0018] The phase of the line back electromotive force between phase C and phase A lags behind the phase of the back electromotive force in phase A by 210 degrees.

[0019] Preferably, the transfer function of the cascaded second-order generalized integrator quadrature signal generator combined with a frequency-locked loop is as follows:

[0020] The transfer function of the filtered line back electromotive force is as follows:

[0021]

[0022] The transfer function of the orthogonal signal of the line back electromotive force is as follows:

[0023]

[0024] In the formula, Let be the transfer function of the filtered line back electromotive force. For the Laplace operator, The input signal is the reconstructed line back electromotive force. This is the output signal of the second-stage, second-order generalized integrator quadrature signal generator, i.e., the filtered line back electromotive force. For the gain of the first-stage second-order generalized integrator quadrature signal generator, This is the gain of the second-stage second-order generalized integrator quadrature signal generator. The estimated angular frequency of the input signal. Let be the transfer function of the orthogonal signal of the line back electromotive force. It is the orthogonal signal of the output signal of the second-stage second-order generalized integrator orthogonal signal generator, that is, the orthogonal signal of the line back electromotive force.

[0025] Preferably, the phase-locked loop (PLL) is a cascaded second-order generalized integrator (GII), and the transfer function of the PLL is as follows:

[0026]

[0027]

[0028] In the formula, Let be the transfer function of the phase-locked loop. For the Laplace operator, The true line back electromotive force phase angle. To estimate the phase angle of the line back electromotive force, This is the true linear back electromotive force angular frequency. To estimate the angular frequency of the line back electromotive force, The magnitude of the back electromotive force is denoted by . This is the filtered back electromotive force. It is an orthogonal signal of the line back electromotive force. This is the proportionality coefficient. is the integral coefficient.

[0029] Preferably, the position of the motor is obtained by relating the phase relationship between the back electromotive force of the combined line and the back electromotive force of A, as follows:

[0030] When the motor rotates forward, the electrical angle of the motor rotor is equal to the phase of the linear back electromotive force between phases A and B of the motor. The difference, or the electrical angle of the motor rotor, is the phase of the linear back electromotive force between phases B and C of the motor. The sum of, or the electrical angle of the motor rotor, is the phase of the linear back electromotive force between phase C and phase A of the motor. the sum of;

[0031] When the motor reverses, the electrical angle of the motor rotor is... The difference between the electrical angle of the motor rotor and the angle when the motor is rotating forward.

[0032] Preferably, the process for determining whether the motor rotates forward or backward is as follows:

[0033] The first moment when the voltage at the two phase terminals is greater than the voltage at the second phase terminal and also greater than the voltage threshold is recorded as time point 2. And record at the time The voltage value of the two-phase terminal voltage is and ,in For a moment The voltage at the first phase terminal, For a moment The voltage at the second phase terminal;

[0034] The first moment when the voltage at the first phase terminal is less than the voltage at the second phase terminal and the voltage at the second phase terminal is greater than the voltage threshold is denoted as moment 1. And record at the time The voltage value of the two-phase terminal voltage is and ,in For a moment The voltage at the first phase terminal, For a moment The voltage at the second phase terminal;

[0035] If satisfied and If the motor rotates forward, then it will rotate in the correct direction; otherwise, it will rotate in the opposite direction. and If it does, the motor will reverse.

[0036] This invention provides a method for speed-driven restarting of a permanent magnet synchronous motor based on two-phase terminal voltage detection. It reconstructs the back electromotive force (EMF) generated by the motor's rotation based on two-channel terminal voltage sampling. An orthogonal signal of the back EMF is constructed using a two-stage cascaded generalized integrator. The frequency and phase information of the back EMF are then extracted from the orthogonal signal pair via a phase-locked loop (PLL). This invention reduces hardware circuitry, lowers hardware costs and complexity, while improving system reliability. It also reduces the number of ADC sampling pins required by the controller, making it suitable for microcontrollers with limited resources. Furthermore, this invention determines the motor's rotation direction by observing the changing trends of the two-channel terminal voltages. Compensation is achieved based on the phase relationship between the back EMF and the rotor's electrical position, enabling the observation of rotor position and speed. This allows the control system to quickly and seamlessly initiate speed-driven restarting, effectively avoiding the influence of line voltage sampling bias on position estimation and achieving rapid and accurate tracking of the motor's position and speed. Attached Figure Description

[0037] Figure 1 This is a flowchart of a method for speed-driven re-starting of a permanent magnet synchronous motor with two-phase terminal voltage detection according to the present invention;

[0038] Figure 2 This is the terminal voltage sampling circuit of the present invention;

[0039] Figure 3 The waveforms of the opposite electromotive force and line back electromotive force of the motor in forward and reverse rotation of the present invention are shown.

[0040] Figure 4 This is a block diagram of the orthogonal signal generator based on a second-order generalized integrator and a frequency-locked loop according to the present invention.

[0041] Figure 5 This is a block diagram of the cascaded second-order generalized integrator orthogonal signal generator incorporating a frequency-locked loop, as described in this invention.

[0042] Figure 6 This is a block diagram of the phase-locked loop of the cascaded second-order generalized integrator of the present invention;

[0043] Figure 7This is a diagram showing the relationship between the input signal and the phase of the phase-locked loop of the present invention;

[0044] Figure 8 This is a schematic diagram of the judgment points under the forward and reverse rotation conditions of the motor in this invention.

[0045] Figure 9 This is a diagram showing the experimental results of a static start-up in this invention.

[0046] Figure 10 This is a diagram showing the experimental results of forward-rotating belt speed re-throwing in the experiment of this invention;

[0047] Figure 11 This is a diagram showing the experimental results of reversing the belt speed and re-throwing in the experiment of this invention. Detailed Implementation

[0048] 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to limit the invention.

[0050] To overcome the problems of high hardware cost and poor system robustness of existing sensorless speed-based re-switching methods for permanent magnet synchronous motors, this invention provides a method for smooth speed-based re-switching of permanent magnet synchronous motors by only collecting the voltage of two phase terminals. This reduces the number of terminal voltage samples and the corresponding analog-to-digital converter pins of the microcontroller, thereby improving system reliability.

[0051] The two-phase terminal voltage detection method for re-energizing a permanent magnet synchronous motor based on belt speed is specifically a sensorless control method for re-energizing a permanent magnet synchronous motor based on belt speed. Figure 1 As shown, the specific steps are as follows:

[0052] Step 1: Combine the three phases of the motors in pairs and collect the voltage of two phases in any combination.

[0053] First, collect the voltage at any two phase terminals of the motor. and (or and ,or and ),in The voltage of motor A relative to ground. The voltage of motor B relative to ground. This represents the voltage between motor C and ground. When the microcontroller acquires the terminal voltage, since the terminal voltage is much larger than the microcontroller's maximum voltage acquisition range, it needs to be divided into a voltage range that the microcontroller can acquire using a resistor divider circuit before acquisition. The sampling circuit is as follows: Figure 2 As shown, R1~R6 are the voltage divider resistors of the terminal voltage divider circuit.

[0054] Step 2: Reconstruct the line back electromotive force based on the collected two-phase terminal voltages, and derive the phase relationship between the line back electromotive force and the back electromotive force of phase A.

[0055] A PMSM can be equivalent to a three-phase symmetrical load, where N is the motor neutral point. Line voltage refers to the voltage between two phases. The line voltage between any two phases can be constructed by subtracting the terminal voltages of any two phases; this is the line back electromotive force generated when the motor rotates. The formula for reconstructing the line voltage from the terminal voltages is as follows:

[0056]

[0057] In the formula, , and These are the three-phase voltages of motors A, B, and C, respectively. This is the voltage between the neutral point of the motor and ground.

[0058]

[0059] In the formula, , and These are the AB line voltage, BC line voltage, and CA line voltage of the motor, respectively.

[0060] When the motor is running at speed, the amplitude of the line voltage, i.e., the line back electromotive force, is related to the motor's electrical angular frequency:

[0061]

[0062] In the formula, The electric angular frequency of the motor. For permanent magnet flux linkage in motors.

[0063] The expressions for the instantaneous values ​​of the three-phase back electromotive force and the line back electromotive force when the motor rotates forward and reverse are as follows:

[0064]

[0065]

[0066] In the formula, , and These are the three-phase opposite electromotive forces of motors A, B, and C, respectively. , and These are the back electromotive forces (EMFs) of lines AB and BC, and the back EMF of line CA, respectively. For time indexing.

[0067] When the motor rotates forward, the motor's electrical angular frequency is... It is a positive value; when the motor reverses, the motor's electrical angular frequency is... The values ​​are negative. Assuming the rotational speed is constant and non-zero, the waveforms of the opposite electromotive force and line back electromotive force for forward and reverse rotation of the motor are as follows: Figure 3 As shown. The phase relationship between the line back electromotive force and the back electromotive force of phase A can be derived from the above formula and waveform, as follows: Line back electromotive force between phase A and phase B. The phase of phase B leads the phase of the back electromotive force (EMF) of phase C by 30 degrees; the line back EMF between phases B and C The phase of phase C lags behind the phase of the back electromotive force (EMF) of phase A by 90 degrees; the linear back EMF between phase C and phase A... The phase of the back electromotive force (EMF) lags behind the phase of the back EMF by 210 degrees. Therefore, by obtaining the phase information of the back EMF, the position information of the motor rotor can be derived.

[0068] Step 3: Filter the reconstructed line back EMF by combining a cascaded second-order generalized integral orthogonal signal generator with a frequency-locked loop, and construct an orthogonal signal pair of the line back EMF.

[0069] The sampling noise and external interference signals of the terminal voltage sampling signal can cause noise in the reconstructed line back EMF, affecting the signal quality and the accuracy of the estimation results. However, a quadrature signal generator (QSG) based on a second-order generalized integrator (SOGI) and a frequency-locked loop (FLL) can filter high-order harmonics in the signal and has low sensitivity to phase angle jumps. Therefore, the reconstructed line back EMF can be filtered using a quadrature signal generator (SOGI-QSG-FLL) based on a second-order generalized integrator and a frequency-locked loop, constructing an orthogonal signal pair of the line back EMF. The block diagram of SOGI-QSG-FLL is shown below. Figure 4 As shown, the transfer function is as follows:

[0070] The transfer function of the filtered line back electromotive force is as follows:

[0071]

[0072] The transfer function of the orthogonal signal of the line back electromotive force is as follows:

[0073]

[0074] The transfer function of FLL is:

[0075]

[0076] In the formula, Let be the transfer function of the filtered line back electromotive force. For the Laplace operator, The input signal is the reconstructed line back electromotive force. The output signal of the second-order generalized integrator quadrature signal generator (SOGI-QSG) is the filtered line back electromotive force. The gain of the second-order generalized integrator quadrature signal generator. This refers to the orthogonal signal of the output signal of a second-order generalized integrator orthogonal signal generator, specifically the orthogonal signal of the line back electromotive force. The estimated angular frequency of the input signal. To estimate the initial value of the angular frequency, Let be the transfer function of the orthogonal signal of the line back electromotive force. For FLL transfer function, For the error gain of FLL, The amplitude of the input signal.

[0077] This embodiment further considers the DC component introduced by the controller sampling conversion and device parameter differences, which causes errors in the SOGI-QSG, and the output signal generated by the SOGI-QSG. It exhibits significant suppression characteristics against DC components and provides quadrature output signals. Sensitive to input DC offset, a cascaded second-order generalized integrator (CGI) can be used to eliminate DC offset, reduce output error, and construct a symmetrical quadrature signal pair with line back electromotive force. The block diagram of a cascaded second-order generalized integrator-quadrature signal generator (CGI-QSG) combined with a frequency-locked loop is shown below. Figure 5 As shown, its transfer function is as follows:

[0078] The transfer function of the filtered line back electromotive force is as follows:

[0079]

[0080] The transfer function of the orthogonal signal of the line back electromotive force is as follows:

[0081]

[0082] The transfer function of FLL is:

[0083]

[0084] In the formula, Let be the transfer function of the filtered line back electromotive force. For the Laplace operator, The input signal is the reconstructed line back electromotive force. The output signal of the second-stage second-order generalized integrator quadrature signal generator (SOGI-QSG) is the filtered line back electromotive force. For the gain of the first-stage second-order generalized integrator quadrature signal generator, This is the gain of the second-stage second-order generalized integrator quadrature signal generator. The estimated angular frequency of the input signal. To estimate the initial value of the angular frequency, Let be the transfer function of the orthogonal signal of the line back electromotive force. The orthogonal signal of the output signal of the second-stage second-order generalized integrator orthogonal signal generator is the orthogonal signal of the line back electromotive force, where... and This is the orthogonal signal pair of the final constructed line back electromotive force.

[0085] Step 5: Use the quadrature signal pair of the line back EMF as the input of the phase-locked loop, extract the phase and frequency of the line back EMF, and combine the phase relationship between the line back EMF and the back EMF of A to obtain the position and speed of the motor.

[0086] In this embodiment, the quadrature signal pair of the line back electromotive force generated by CGI-QSG is used as the input of the phase-locked loop (PLL) to extract the phase and frequency information of the line back electromotive force, thereby obtaining the position and speed information of the motor. Simultaneously, the amplitude of the line back electromotive force is calculated using the quadrature signal pair. If the motor is initially stationary or its speed is below a certain threshold, the amplitude of its linear back electromotive force (EMF) is almost zero; otherwise, the motor will have a certain amplitude of linear back EMF, which is used to determine whether the motor has started from a standstill. A block diagram of a phase-locked loop (CGI-PLL) incorporating a cascaded generalized integrator-phase-locked loop is shown below. Figure 6 As shown, the transfer function is as follows:

[0087] PLL transfer function:

[0088]

[0089] Calculation of the amplitude of the line back electromotive force:

[0090]

[0091] In the formula, Let be the transfer function of the phase-locked loop. For the Laplace operator, The true line back electromotive force phase angle. To estimate the phase angle of the line back electromotive force, This is the true linear back electromotive force angular frequency. The estimated linear back electromotive force angular frequency is used in conjunction with the number of motor pole pairs. Calculate the motor speed , The magnitude of the back electromotive force is denoted by . This is the filtered back electromotive force. It is an orthogonal signal of the line back electromotive force. This is the proportionality coefficient. The integral coefficient is... The q-axis voltage is the line voltage. This represents the d-axis voltage.

[0092] The correspondence between PLL input signals and phases is as follows: Figure 7 As shown, by combining the phase relationship between the line back EMF and the back EMF at position A, and the relationship between the back EMF at position A and the rotor position, the electrical position information of the rotor can be calculated. The phase of the back electromotive force. Electrical angle with motor rotor The phase relationship between them is shown in Table 2.

[0093] Table 2. Phase of Linear Back Electromotive Force Electrical angle with motor rotor Phase relationship between

[0094]

[0095] Step 6: If the amplitude of the back electromotive force is less than the amplitude threshold, switch to normal start mode; otherwise, if the motor reverses, switch to reverse speed re-start mode based on the motor's position and speed; if the motor rotates forward, switch to forward speed re-start mode based on the motor's position and speed.

[0096] Since the direction of motor rotation cannot be determined by a single-line back electromotive force, it is necessary to determine it based on the instantaneous value changes of the two-phase terminal voltages. This embodiment provides a determination method, taking the acquisition of phase A terminal voltage and phase B terminal voltage as an example. The first phase terminal voltage is the phase A terminal voltage, and the second phase terminal voltage is the phase B terminal voltage. The determination points under forward and reverse rotation conditions are as follows: Figure 8 As shown:

[0097] The first moment when the voltage at the two phase terminals is greater than the voltage at the second phase terminal and also greater than the voltage threshold is recorded as time point 2. And record at the time The voltage value of the two-phase terminal voltage is and ,in For a moment The voltage at the first phase terminal, For a moment The second phase terminal voltage; the first moment when the first phase terminal voltage is less than the second phase terminal voltage and the second phase terminal voltage is greater than the voltage threshold is denoted as moment. And record at the time The voltage value of the two-phase terminal voltage is and ,in For a moment The voltage at the first phase terminal, For a moment The voltage at the second phase terminal; if it satisfies and If the motor rotates forward, then it will rotate in the correct direction; otherwise, it will rotate in the opposite direction. and If the voltage reading is positive, the motor will reverse; otherwise, other cases are considered invalid, and the voltage will be re-acquired to determine the motor's forward and reverse rotation. Phase A is the first phase, and phase B is the second phase; in Phase B is the first phase, and phase C is the second phase; in In the middle, phase C is the first phase, and phase A is the second phase.

[0098] After obtaining the accurate position and speed of the motor, the first step is to determine the back electromotive force (EMF): if the amplitude of the back EMF is less than the amplitude threshold, it indicates that the initial state of the PMSM is stationary or the speed is lower than the set speed threshold for belt speed re-start (close to zero speed). In this case, the normal start mode is directly switched to (usually, the initial rotor position detection of the motor is completed first (such as high-frequency injection positioning), and then the motor is smoothly accelerated from stationary / low speed to the target speed through open-loop / closed-loop control (such as V / F start, direct torque control, etc.); otherwise, the belt speed re-start mode is entered.

[0099] In the belt-speed re-start mode, different belt-speed re-start modes are used depending on the forward and reverse rotation of the motor: When the motor is determined to be rotating in reverse, the reverse belt-speed re-start mode is switched to: at the moment the controller intervenes, the motor rotor position and speed estimated and compensated by CGI-PLL are assigned to the sensorless observer and controller, and the motor is first decelerated to zero, and then accelerated from zero speed to enter forward rotation; when the motor is determined to be rotating in forward rotation, the forward belt-speed re-start mode is switched to: at the moment the controller intervenes, the motor rotor position and speed estimated and compensated by CGI-PLL are assigned to the sensorless observer and controller, and then closed-loop control is directly implemented to ensure that the PMSM system smoothly switches to the normal operating mode. In this way, the system will smoothly run from the state before the controller intervenes to the state after the driver intervenes, and finally reach a stable state. The controller and sensorless observer involved are conventional devices for motor belt-speed re-start, and will not be described in detail in this embodiment.

[0100] Using the method described in this embodiment for motor speed rev-up control, the following experimental results were obtained:

[0101] (1) Start from a standstill: such as Figure 9 As shown, during a standstill start, the motor starts normally after the line voltage amplitude is less than the set value for a certain period of time. The yellow waveform represents the voltage at phase A, the red waveform represents the current at phase A, and the blue waveform represents the estimated electrical angle of the motor rotor.

[0102] (2) Forward rotation with speed re-throw: such as Figure 10 As shown, during the forward-rotating belt-speed re-engagement phase, the motor is in a forward-rotating state. During this phase, the method of this invention can quickly and accurately track the actual position and speed of the motor. After switching into operation, the phase current is smooth and without impact. The estimated position information shows a natural transition during the switching process, proving the accuracy of the estimated position information during the belt-speed re-engagement phase. The yellow waveform represents the voltage at phase A, the red waveform represents the current at phase A, and the blue waveform represents the estimated electrical angle of the motor rotor.

[0103] (3) Reversal and speed-up re-throw: such as Figure 11 As shown, during the reverse belt-speed re-engagement phase, the motor is rotating in the opposite direction. This method can quickly and accurately track the actual position and speed of the motor during this phase. After switching into operation, the current is smooth and without impact, and the estimated position during the switching process is seamless. The yellow waveform represents the voltage at phase A, the red waveform represents the current at phase A, and the blue waveform represents the estimated electrical angle of the motor rotor.

[0104] In summary, the method of the present invention can achieve rapid and accurate tracking of the motor position and speed in the entire speed range of PMSM, enabling the control system to quickly, smoothly, and without impact the speed-up restart.

[0105] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0106] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A method for re-energizing a permanent magnet synchronous motor with belt speed based on two-phase terminal voltage detection, characterized in that, The method for re-energizing a permanent magnet synchronous motor with speed detection of two-phase terminal voltage includes: The three phases of the motors are combined in pairs, and the voltage of two phases in any one of the combinations is collected. The line back electromotive force is reconstructed based on the collected two-phase terminal voltages, and the phase relationship between the line back electromotive force and the back electromotive force of phase A is derived. The reconstructed line back electromotive force is filtered by a cascaded second-order generalized integral orthogonal signal generator combined with a frequency-locked loop, and an orthogonal signal pair of the line back electromotive force is constructed. The quadrature signal pair of the line back electromotive force is used as the input of the phase-locked loop to extract the phase and frequency of the line back electromotive force. Combined with the phase relationship between the line back electromotive force and the back electromotive force of A, the position and speed of the motor are obtained. If the amplitude of the back electromotive force is less than the amplitude threshold, the system switches to normal start mode; otherwise, if the motor reverses, the system switches to reverse speed re-start mode based on the motor's position and speed; if the motor rotates forward, the system switches to forward speed re-start mode based on the motor's position and speed.

2. The method for re-energizing a permanent magnet synchronous motor with belt speed detection based on two-phase terminal voltage detection according to claim 1, characterized in that, The phase relationship between the line back electromotive force and the back electromotive force of A is as follows: The phase of the line back electromotive force between phase A and phase B leads the phase of the back electromotive force in phase A by 30 degrees. The phase of the back electromotive force between phase B and phase C lags behind the phase of the back electromotive force between phase A by 90 degrees. The phase of the line back electromotive force between phase C and phase A lags behind the phase of the back electromotive force in phase A by 210 degrees.

3. The method for re-energizing a permanent magnet synchronous motor with belt speed detection based on two-phase terminal voltage according to claim 1, characterized in that, The transfer function of the cascaded second-order generalized integrator quadrature signal generator combined with a frequency-locked loop is as follows: The transfer function of the filtered line back electromotive force is as follows: The transfer function of the orthogonal signal of the line back electromotive force is as follows: In the formula, Let be the transfer function of the filtered line back electromotive force. For the Laplace operator, The input signal is the reconstructed line back electromotive force. This is the output signal of the second-stage, second-order generalized integrator quadrature signal generator, i.e., the filtered line back electromotive force. For the gain of the first-stage second-order generalized integrator quadrature signal generator, This is the gain of the second-stage second-order generalized integrator quadrature signal generator. The estimated angular frequency of the input signal. Let be the transfer function of the orthogonal signal of the line back electromotive force. It is the orthogonal signal of the output signal of the second-stage second-order generalized integrator orthogonal signal generator, that is, the orthogonal signal of the line back electromotive force.

4. The method for re-energizing a permanent magnet synchronous motor with belt speed detection based on two-phase terminal voltage detection according to claim 1, characterized in that, The phase-locked loop is a phase-locked loop of a cascaded second-order generalized integrator, and the transfer function of the phase-locked loop of the cascaded second-order generalized integrator is as follows: In the formula, Let be the transfer function of the phase-locked loop. For the Laplace operator, The true line back electromotive force phase angle. To estimate the phase angle of the line back electromotive force, This is the true linear back electromotive force angular frequency. To estimate the angular frequency of the line back electromotive force, The magnitude of the back electromotive force is denoted by . This is the filtered back electromotive force. It is an orthogonal signal of the line back electromotive force. This is the proportionality coefficient. is the integral coefficient.

5. The method for re-energizing a permanent magnet synchronous motor with belt speed detection based on two-phase terminal voltage according to claim 2, characterized in that, The position of the motor is obtained by relating the phase relationship between the back electromotive force of the combined line and the back electromotive force of A, as follows: When the motor rotates forward, the electrical angle of the motor rotor is equal to the phase of the linear back electromotive force between phases A and B of the motor. The difference, or the electrical angle of the motor rotor, is the phase of the linear back electromotive force between phases B and C of the motor. The sum of, or the electrical angle of the motor rotor, is the phase of the linear back electromotive force between phase C and phase A of the motor. the sum of; When the motor reverses, the electrical angle of the motor rotor is... The difference between the electrical angle of the motor rotor and the angle when the motor is rotating forward.

6. The method for re-energizing a permanent magnet synchronous motor with belt speed detection based on two-phase terminal voltage detection according to claim 1, characterized in that, The process for determining whether the motor rotates forward or backward is as follows: The first moment when the voltage at the two phase terminals is greater than the voltage at the second phase terminal and also greater than the voltage threshold is recorded as time point 2. And record at the time The voltage value of the two-phase terminal voltage is and ,in For a moment The voltage at the first phase terminal, For a moment The voltage at the second phase terminal; The first moment when the voltage at the first phase terminal is less than the voltage at the second phase terminal and the voltage at the second phase terminal is greater than the voltage threshold is denoted as moment 1. And record at the time The voltage value of the two-phase terminal voltage is and ,in For a moment The voltage at the first phase terminal, For a moment The voltage at the second phase terminal; If satisfied and If the motor rotates forward, then it will rotate in the correct direction; otherwise, it will rotate in the opposite direction. and If it does, the motor will reverse.

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