Instantaneous power control method for permanent magnet synchronous generator without position sensor

Abstract

The invention discloses an instantaneous power control method for a permanent magnet synchronous generator without a position sensor. A direct current power supply system comprises a permanent magnet synchronous motor, a power electronic converter and a control framework. The permanent magnet synchronous motor works in a power generation state, the rotor is driven to rotate through the engine or the transmission device connected to the engine, the stator winding cuts a magnetic field generated by the rotor permanent magnet, and then alternating electromotive force is induced in the stator winding. The control architecture controls the power electronic converter to work in a rectification state and provides stable voltage output for the load. According to the control method provided by the invention, the sliding-mode observer, the phase-locked loop and instantaneous power control are combined, and non-inductive observation of the rotor position and decoupling control of active power and reactive power are realized. Moreover, the size of the permanent magnet synchronous generator is reduced, the problem of signal failure easily occurring under the severe working conditions of vibration, high temperature and the like is effectively avoided, and the reliability of long-term operation of the system is improved.

Description

A sensorless method for instantaneous power control of permanent magnet synchronous generator Technical Field

[0001] This invention relates to the field of permanent magnet synchronous generator control, and more specifically, to a sensorless method for instantaneous power control of a permanent magnet synchronous generator. Background Technology

[0002] In modern ships, aircraft, and special equipment, DC power supply systems have gradually become the core of power and control, undertaking the task of providing stable power to propulsion, control, and various auxiliary systems. These equipment typically operate in harsh environments with limited space, yet place high demands on the performance of the power supply system. In environments with strong electromagnetic interference, traditional rotor position sensors are susceptible to interference, leading to signal distortion and causing inaccurate control of permanent magnet synchronous generators, significantly reducing system reliability and efficiency. Sensorless technology based on sliding mode observers and phase-locked loops can estimate rotor position in environments with strong electromagnetic interference, eliminating reliance on physical sensors. Combined with instantaneous power control, it can accurately decouple active and reactive power, maintain a high power factor, and avoid harmonic losses. Sensorless technology offers strong anti-interference capabilities and high reliability, while instantaneous power control combines high efficiency and rapid dynamic response. The combination of these two technologies enables stable and precise power control and efficient equipment operation even in environments with severe electromagnetic interference.

[0003] Patent CN115296573A discloses a sensorless voltage regulation control method for a permanent magnet synchronous starter generator with high dynamic response. In the voltage regulation generation state, a sliding mode observer algorithm is used to estimate the motor speed and rotor position, and a dual closed-loop structure of voltage outer loop and current inner loop is used for voltage regulation control of the motor. While this method helps improve voltage regulation, it does not offer solutions for improving anti-interference performance or operational stability in harsh environments. Summary of the Invention

[0004] The present invention addresses the technical problems in the prior art by providing a sensorless instantaneous power control method for permanent magnet synchronous generators, thereby overcoming the aforementioned deficiencies in the prior art.

[0005] A sensorless instantaneous power control method for a permanent magnet synchronous generator (PMSG) is applied to DC charging systems in ships, aircraft, and special equipment. The DC power supply system includes a PMSG, a power electronic converter, and a sensorless control architecture. The PMSG operates in generator mode, driving the rotor to rotate via an engine or a transmission device connected to the engine. This causes the stator windings to cut the magnetic field generated by the rotor's permanent magnets, inducing an alternating electromotive force (EMF) in the stator windings. The power electronic converter is a three-phase full-bridge rectifier operating in rectification mode, using a sinusoidal pulse width signal to drive six semiconductor switches, converting the three-phase AC output from the PMSG into stable DC power. The sensorless control architecture includes a control loop and a rotor position estimation section. The rotor position estimation method estimates the back EMF using a sliding mode observer, combined with a phase-locked loop and phase compensation, to calculate the rotor position and speed. The control loop is derived based on instantaneous power theory and can achieve decoupled control of active and reactive power.

[0006] Furthermore, the control loop includes an instantaneous power calculation loop, a rotor angular position and angular velocity calculation loop, an external voltage control loop, and an internal instantaneous power control loop.

[0007] Furthermore, the input to the controller of the voltage control loop is the difference between the output DC voltage setpoint and the feedback value, and the output is the desired current. This current is multiplied by the DC voltage to obtain the active power reference value.

[0008] Furthermore, the instantaneous power control loop includes an active power control loop and a reactive power control loop. The input of the active power control loop is the difference between the active power reference value and the feedback value, and the input of the reactive power control loop is the rated reactive power difference. After decoupling and compensating the outputs of the active power controller and the reactive power controller, the required quadrature and direct axis voltage components can be obtained. After coordinate transformation and space vector pulse width modulation, three sets of PWM drive signals can be obtained.

[0009] Furthermore, based on the quadrature and direct axis components of the three-phase output current of the permanent magnet synchronous generator in the two-phase rotating dq coordinate system and the rotational speed, the active power feedback value and the difference between the rated reactive power can be calculated, thereby achieving instantaneous power control; according to instantaneous power theory, instantaneous active power and instantaneous reactive power can be defined by Formula 1:

[0010] Where P is the instantaneous active power, Q is the instantaneous reactive power, and i α and i β These are the components of the stator current on the α-axis and β-axis, respectively. α and u βThese are the components of the stator terminal voltage along the α-axis and β-axis, respectively; for a permanent magnet synchronous generator, the terminal voltage can be expressed as Equation 2:

[0011] Among them, e α and e β These are the back electromotive force components on the α-axis and β-axis, respectively, L s and R s These are the stator winding inductance and resistance, respectively; the back electromotive force can be expressed as Equation 3:

[0012] Where, ω e It is the electric angular velocity, ψ f It is a permanent magnet flux linkage, θ e This refers to the rotor angular position; substituting Formula 1 and Formula 2 into the formulas for instantaneous active power and instantaneous reactive power, we can obtain Formula 4: .

[0013] Furthermore, if we define the angle between the stator current vector and the rotor flux linkage vector as γ, then the stator current can be expressed as Equation 5:

[0014] Where I s This is the magnitude of the stator current vector in steady state. If the magnitude of the stator current vector and the angle between the stator current vector and the rotor flux vector remain unchanged, then Formula Six can be obtained:

[0015] Substituting Formula 5 and Formula 6 into Formula 4, we obtain Formula 7:

[0016] Furthermore, instantaneous power is a function of speed, stator current amplitude, and stator current phase. When the stator current amplitude is constant and the angle between the stator current and the rotor flux vector is 90 degrees, the instantaneous active power reaches its maximum value, while the instantaneous reactive power reaches its minimum value. At this time, the active power and reactive power can be expressed as Equation 8:

[0017] In the dq coordinate system, the relationship between the magnitude and phase angle of the quadrature and direct axis currents and the stator current vectors can be expressed by Equation Nine:

[0018] Substituting Formula 9 into Formula 7, we obtain Formula 10: .

[0019] Furthermore, Formula 10 can be used for instantaneous power detection. When the reactive power is at its minimum, the system operates at unity power factor. Formula 10 shows that the reactive power is divided into two parts: one part is the reactive power acting on the stator inductor, and the other part is the reactive power exchanged between the rotor flux linkage and the stator flux linkage. When the reactive power acting on the stator inductor is at its minimum, the reactive power can be minimized by controlling the direct-axis current. Therefore, the difference in rated instantaneous reactive power can be expressed as Formula 11:

[0020] When the system is in steady state, Equation 11 is 0.

[0021] Furthermore, a sliding mode observer is used to estimate the back electromotive force of the permanent magnet synchronous generator, and then a phase-locked loop is used to obtain the precise rotor angular position and angular velocity; the state equation of the permanent magnet synchronous generator in the two-phase stationary α-β coordinate system can be expressed as Equation Twelve:

[0022] According to sliding mode observer theory, the mathematical model of the current observer in the α-β coordinate system can be expressed as Equation Thirteen:

[0023] In the formula and It is an estimated value of the stator current in the α-β coordinate system. and It is an estimate of the back electromotive force in the α-β coordinate system, z α and z β It is a control function, which uses a saturation function, and can be expressed as Formula Fourteen:

[0024] In the formula, k is the back electromotive force of the permanent magnet synchronous generator, while the current difference is defined as the sliding surface, as shown in Formula 15:

[0025] Therefore, the relationship between the saturation function and the sliding surface can be transformed into Formula Sixteen:

[0026] In the formula, Δ represents the boundary layer. The current error signal when the system is stable contains back EMF information. By passing through a low-pass filter, the back EMF can be obtained as shown in Formula 17.

[0027] Where ω c It is the resonant frequency of the low-pass filter.

[0028] Furthermore, the angle output by the phase-locked loop is used for coordinate transformation to convert the observed back electromotive force in the α-β coordinate system into a back electromotive force component in the dq coordinate system. By using a PI controller to control the d-axis component of the back electromotive force to be 0, the angular velocity information can be obtained. After integration, the angular position can be obtained.

[0029] Compared with existing technologies, the significant advantages of this invention are as follows: 1. The sliding mode observer phase-locked loop technology has significant advantages in scenarios with strong electromagnetic interference. It does not rely on physical position sensors such as Hall effect sensors and encoders, which saves hardware costs and avoids signal distortion caused by sensor interference, making it extremely robust. At the same time, by estimating the back electromotive force through the sliding mode observer and combining phase-locked loop and phase compensation technology, the rotor position and speed can be accurately obtained, which greatly improves the reliability of the system in harsh environments.

[0030] 2. Instantaneous power control can accurately decouple active and reactive power, maintain high power factor operation of equipment, significantly improve energy conversion efficiency, and avoid additional losses caused by low-frequency harmonics. Combined with sliding mode observer phase-locked loop technology, it can still respond quickly and control power stably under complex operating conditions such as speed fluctuations or electromagnetic interference. It can also achieve constant DC bus voltage, and has excellent dynamic response and robustness. Attached Figure Description

[0031] Figure 1 is a circuit diagram of a preferred embodiment of the permanent magnet synchronous generator control system of the present invention; Figure 2 is a control block diagram of a preferred embodiment of the sensorless control architecture of the permanent magnet synchronous generator of the present invention; Figure 3 is a sliding mode observer phase-locked loop control block diagram of a preferred embodiment of the sensorless control architecture of the permanent magnet synchronous generator of the present invention; Figure 4 is a simulation result diagram of the sliding mode observer phase-locked loop of the sensorless control architecture of the permanent magnet synchronous generator of the present invention; Figure 5 is a software control flowchart of the permanent magnet synchronous generator control system of the present invention. The specific embodiments are described below to clearly illustrate the technical features of the present invention. The invention will be described in detail below through specific embodiments and in conjunction with the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the invention. However, the invention can also be implemented in other ways different from those described herein. Therefore, the scope of protection of the invention is not limited to the specific embodiments disclosed below. In the present invention, unless otherwise expressly specified and limited, the first feature "on" or "below" the second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. In the description of this specification, references to terms such as "an embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that the specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples.

[0032] Example 1 This example provides a permanent magnet synchronous generator control system. Figure 1 is a circuit diagram of a preferred embodiment of the permanent magnet synchronous generator control system of the present invention. The hardware circuit of the permanent magnet synchronous generator control system of the present invention mainly includes three parts: a permanent magnet synchronous generator, a power electronic converter, and an electrical load.

[0033] The permanent magnet synchronous motor described above operates in generator mode. Mechanical power drives the rotor to rotate, causing the stator windings to cut the magnetic field generated by the rotor's permanent magnets, thereby inducing an alternating electromotive force e in the stator windings. x (x=a,b,c). The inductance, resistance, and current flowing through the three-phase windings are respectively L... s R s and i x (x=a,b,c).

[0034] The power electronic converter is a three-phase full-bridge rectifier, operating in rectification mode. The semiconductor switches S used in the upper and lower bridge arms of the same phase are... xp and S xn (x=a,b,c) are complementary conductions. Therefore, only three sets of drive signals S are needed. x (x=a,b,c) can convert the three-phase AC output of the permanent magnet synchronous generator into stable DC power with a voltage value of U. dc .

[0035] The electrical load includes a filter capacitor and a load. The function of the filter capacitor is to filter out the output current i of the power electronic converter. dc High-frequency components i CThis leads to a more stable DC voltage i L .

[0036] Figure 2 is a control block diagram of a preferred embodiment of the sensorless control architecture for a permanent magnet synchronous generator according to the present invention. The control block diagram of the permanent magnet synchronous generator control system of the present invention includes two main parts: dual closed-loop control and rotor position estimation.

[0037] The dual closed-loop control section includes an instantaneous power calculation loop, an external voltage control loop, and an internal instantaneous power control loop.

[0038] The voltage control loop uses a PI controller, whose input is the output DC voltage setpoint U. dc * With feedback value U dc The difference between the two is the desired current output. Multiplying this current by the DC voltage yields the active power reference value P. * .

[0039] The instantaneous power control loop includes an active power control loop and a reactive power control loop. In this example, both instantaneous power control loops use PI controllers. The input to the active power controller is the active power reference value P. * The difference between the feedback value P and the input of the reactive power controller is the rated reactive power difference ΔQ. * .

[0040] After decoupling and compensating the outputs of the active power controller and the reactive power controller, the quadrature and direct axis voltage components U of the stator winding port a, b, and c voltages to be synthesized can be obtained. d * and U q * After inverse Park transform and space vector pulse width modulation, three sets of driving signals S can be obtained. x (x=a,b,c).

[0041] The instantaneous power calculation step, based on instantaneous power theory and the mathematical model of permanent magnet synchronous motor, can be expressed as follows:

[0042] Based on the inductance L of the permanent magnet synchronous generator s Resistance R s , magnetic flux ψ f The quadrature and direct axis components of the three-phase current in the dq coordinate system q i q and electric angular velocity ω e By calculating the difference between the active power feedback value and the rated reactive power, instantaneous power control can be achieved.

[0043] Figure 3 is a sliding mode observer phase-locked loop control block diagram of a preferred embodiment of the sensorless control architecture for a permanent magnet synchronous generator according to the present invention. The electrical angle θ of the generator is required in the control loop. e and electric angular velocity ω e Used for coordinate transformation and instantaneous power calculation. The permanent magnet synchronous generator control system of this invention uses a sliding mode observer to estimate the back electromotive force, combined with a phase-locked loop and phase compensation, to calculate the rotor position and speed.

[0044] The sliding mode observer is derived based on sliding mode theory, and the input of the PMSG observer is the α-β axis component U of the stator winding port voltage. α and U β α-β axis components of the back electromotive force estimate and and z α and z β The output is the α-β axis components of the stator current estimate. and , can be represented as:

[0045] In the diagram, k represents the back electromotive force of the permanent magnet synchronous generator. The control function uses a saturation function and can be expressed as follows:

[0046] The current error signal when the system is stable contains back electromotive force (EMF) information. By using a low-pass filter, the α-β axis components of the estimated back EMF can be obtained. and .

[0047] The phase-locked loop performs a Park transformation on the α-β axis components of the back EMF estimate to obtain the dq axis components of the back EMF estimate. and .in, The electric angular velocity information can be obtained through PI control. The electric angle can be obtained by integrating the electric angular velocity with respect to time and taking the remainder with respect to 2π. .

[0048] Figure 4 is a schematic diagram of the simulation results of the sliding mode observer phase-locked loop of the sensorless control architecture for permanent magnet synchronous generators of the present invention. The sliding mode observer phase-locked loop can effectively detect the rotor position with a maximum error of no more than 0.3 rad.

[0049] Figure 5 is a software control flowchart of the permanent magnet synchronous generator control system of the present invention. The control flow of the permanent magnet synchronous generator control system is as follows: Step 501, sample the generator stator current I. a I bI c and the output voltage U of the power electronic converter dc .

[0050] Step 502: Obtain the α-β axis components i of the stator current through coordinate transformation. α and i β The α-β axis components of the back electromotive force e are estimated using a sliding diaphragm observer. α and e β .

[0051] Step 503: Obtain the dq-axis component e of the back electromotive force through coordinate transformation. d and e q The electric angular velocity ω is obtained by PI control of the d-axis component of the back electromotive force. e Integrating the angular velocity yields the electrical angle θ. e .

[0052] Step 504, give the output voltage reference value U dc * The difference between this value and the output voltage feedback value is used for PI control to obtain the given current reference value, which is then multiplied by the output voltage feedback value to obtain the active power reference value P*.

[0053] Step 505: Obtain the dq-axis component i of the stator current through coordinate transformation. d and i q Instantaneous power calculations are performed to obtain the active power feedback value P and the rated reactive power difference ΔQ*.

[0054] Step 506: Perform PI control on the given active power value and the difference between active power and rated reactive power, respectively, and decouple the controller output to obtain the dq-axis component u of the stator winding terminal voltage. d and u q .

[0055] Step 507: The stator winding terminal voltage dq axis component is subjected to coordinate transformation and space vector pulse width modulation to obtain a drive signal, which is then sent to the semiconductor switching transistor.

[0056] Example 2: A method for instantaneous power control of a sensorless permanent magnet synchronous generator. The permanent magnet synchronous motor operates in a power generation state, and drives the rotor to rotate through an engine or a transmission device connected to the engine, so that the stator winding cuts the magnetic field generated by the rotor permanent magnet, thereby inducing an alternating electromotive force in the stator winding.

[0057] The power electronic converter is a three-phase full-bridge rectifier that operates in rectification mode. It uses a sinusoidal pulse width signal to drive six semiconductor switches to convert the three-phase AC power output from the permanent magnet synchronous generator into stable DC power.

[0058] The sensorless control architecture includes a control loop and a rotor position estimation part. The rotor position estimation method estimates the back electromotive force through a sliding mode observer, and then calculates the rotor position and speed by combining a phase-locked loop and phase compensation. The control loop is derived based on instantaneous power theory and can achieve decoupled control of active power and reactive power.

[0059] The control loop includes an instantaneous power calculation stage, a rotor angular position and angular velocity calculation stage, an external voltage control loop, and an internal instantaneous power control loop. The voltage control loop's controller input is the difference between the output DC voltage setpoint and the feedback value; the output is the desired current, which is multiplied by the DC voltage to obtain the active power reference value. The instantaneous power control loop includes an active power control loop and a reactive power control loop. The active power control loop's input is the difference between the active power reference value and the feedback value, while the reactive power control loop's input is the rated reactive power difference. After decoupling and compensating the outputs of the active power controller and the reactive power controller, the required synthesized quadrature and direct-axis voltage components can be obtained. Through coordinate transformation and space vector pulse width modulation, three sets of PWM drive signals can be obtained.

[0060] Based on the quadrature and direct axis components of the three-phase output current of the permanent magnet synchronous generator in the two-phase rotating dq coordinate system and the rotational speed, the active power feedback value and the difference between the rated reactive power are calculated, thereby achieving instantaneous power control. According to instantaneous power theory, instantaneous active power and instantaneous reactive power can be defined as follows: (1) Where P is the instantaneous active power, Q is the instantaneous reactive power, and i α and i β These are the components of the stator current on the α-axis and β-axis, respectively. α and u β These are the components of the stator terminal voltage along the α-axis and β-axis, respectively; for a permanent magnet synchronous generator, the terminal voltage can be expressed as: (2) Where, e α and e β These are the back electromotive force components on the α-axis and β-axis, respectively, L s and R s These are the stator winding inductance and resistance, respectively; the back electromotive force can be expressed as: (3) Where, ω e It is the electric angular velocity, ψ f It is a permanent magnet flux linkage, θ e It is the rotor angular position; substituting equations (2) and (3) into equation (1), we can obtain (4) If the angle between the stator current vector and the rotor flux linkage vector is set as γ, then the stator current can be expressed as: (5) Where Is is the magnitude of the stator current vector in steady state. If the magnitude of the stator current vector and the angle between the stator current vector and the rotor flux vector remain unchanged, then the following equation can be obtained: (6) Substituting equations (5) and (6) into equation (4), we can obtain (7) Instantaneous power is a function of speed, stator current amplitude, and stator current phase. When the stator current amplitude is constant and the angle between the stator current and the rotor flux vector is 90 degrees, the instantaneous active power reaches its maximum value, while the instantaneous reactive power reaches its minimum value. At this time, the active power and reactive power can be expressed as: (8) In the dq coordinate system, the relationship between the magnitude and phase angle of the quadrature and direct axis currents and the stator current vectors can be expressed as: (9) Substituting equation (9) into equation (7), we get: (10) The above formula can be used for instantaneous power detection. When the reactive power is at its minimum, the system operates with a unity power factor. Equation (10) shows that the reactive power is divided into two parts: one part is the reactive power acting on the stator inductor, and the other part is the reactive power exchanged between the rotor flux linkage and the stator flux linkage. When the reactive power acting on the stator inductor is at its minimum, the reactive power can be minimized by controlling the direct-axis current. The rated instantaneous reactive power difference can be expressed as: (11) When the system is in steady state, equation (11) is 0.

[0061] The back electromotive force of the permanent magnet synchronous generator is estimated using a sliding mode observer, and then the precise rotor angular position and angular velocity are obtained through a phase-locked loop. The state equation of the permanent magnet synchronous generator in the two-phase stationary α-β coordinate system can be expressed as: (12) According to the sliding mode observer theory, the mathematical model of the current observer in the α-β coordinate system can be expressed as: In equation (13) and It is an estimated value of the stator current in the α-β coordinate system. and It is an estimate of the back electromotive force in the α-β coordinate system, z α and z β It is a control function, which uses a saturation function, and can be expressed as: (14) In the formula, k is the back electromotive force of the permanent magnet synchronous generator, and the current difference is defined as the sliding surface: (15) Therefore, the relationship between the saturation function and the sliding surface can be transformed into: In equation (16), Δ represents the boundary layer. The current error signal when the system is stable contains back EMF information. By passing a low-pass filter, the back EMF can be obtained as follows: (17) where ωc It is the resonant frequency of the low-pass filter.

[0062] The coordinate transformation is performed using the angle output by the phase-locked loop, converting the observed back electromotive force in the α-β coordinate system into a back electromotive force component in the dq coordinate system. By using a PI controller to control the d-axis component of the back electromotive force to be 0, the angular velocity information can be obtained. After integration, the angular position can be obtained.

[0063] Example 3 This example provides an application of a sensorless permanent magnet synchronous generator instantaneous power control method. This method is applied to DC charging systems in ships, aircraft, and special equipment. The DC power supply system includes a permanent magnet synchronous motor, a power electronic converter, and a sensorless control architecture.

[0064] Obviously, the embodiments described above are merely examples for clearly illustrating the present invention and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for instantaneous power control of a sensorless permanent magnet synchronous generator, characterized in that, A DC charging system for use in ships, aircraft, and special equipment includes a permanent magnet synchronous motor (PMSM), a power electronic converter, and a sensorless control architecture. The PMSM operates in generator mode, driving the rotor to rotate via an engine or a transmission connected to the engine. This causes the stator windings to cut the magnetic field generated by the rotor's permanent magnets, inducing an alternating electromotive force (EMF) in the stator windings. The power electronic converter is a three-phase full-bridge rectifier operating in rectification mode. It uses a sinusoidal pulse-width signal to drive six semiconductor switches, converting the three-phase AC output from the PMSM into stable DC power. The sensorless control architecture includes a control loop and a rotor position estimation section. The rotor position estimation method estimates the back EMF using a sliding mode observer, combined with a phase-locked loop and phase compensation, to calculate the rotor position and speed. The control loop is derived based on instantaneous power theory, enabling decoupled control of active and reactive power.

2. The instantaneous power control method for a sensorless permanent magnet synchronous generator according to claim 1, characterized in that, The control loop includes an instantaneous power calculation loop, a rotor angular position and angular velocity calculation loop, an external voltage control loop, and an internal instantaneous power control loop.

3. The instantaneous power control method for a sensorless permanent magnet synchronous generator according to claim 1, characterized in that, The input to the controller of the voltage control loop is the difference between the output DC voltage setpoint and the feedback value, and the output is the desired current. This current is multiplied by the DC voltage to obtain the active power reference value.

4. The instantaneous power control method for a sensorless permanent magnet synchronous generator according to claim 1, characterized in that, The instantaneous power control loop includes an active power control loop and a reactive power control loop. The input of the active power control loop is the difference between the active power reference value and the feedback value, and the input of the reactive power control loop is the rated reactive power difference. After decoupling and compensating the outputs of the active power controller and the reactive power controller, the required quadrature and direct axis voltage components can be obtained. After coordinate transformation and space vector pulse width modulation, three sets of PWM drive signals can be obtained.

5. The instantaneous power control method for a sensorless permanent magnet synchronous generator according to claim 1, characterized in that, Based on the quadrature and direct axis components of the three-phase output current of the permanent magnet synchronous generator in the two-phase rotating dq coordinate system and the rotational speed, the active power feedback value and the difference between the rated reactive power can be calculated, thereby achieving instantaneous power control. According to instantaneous power theory, instantaneous active power and instantaneous reactive power can be defined as Equation 1: Where P is the instantaneous active power, Q is the instantaneous reactive power, and i α and i β These are the components of the stator current on the α-axis and β-axis, respectively. α and u β These are the components of the stator terminal voltage along the α-axis and β-axis, respectively; for a permanent magnet synchronous generator, the terminal voltage can be expressed as Equation 2: Among them, e α and e β These are the back electromotive force components on the α-axis and β-axis, respectively, L s and R s These are the stator winding inductance and resistance, respectively; the back electromotive force can be expressed as Equation 3: Where, ω e It is the electric angular velocity, ψ f It is a permanent magnet flux linkage, θ e This refers to the rotor angular position; substituting Formula 1 and Formula 2 into the formulas for instantaneous active power and instantaneous reactive power, we can obtain Formula 4: 。 6. The instantaneous power control method for a sensorless permanent magnet synchronous generator according to claim 5, characterized in that, If the angle between the stator current vector and the rotor flux linkage vector is set as γ, then the stator current can be expressed as Equation 5: Where I s This is the magnitude of the stator current vector in steady state. If the magnitude of the stator current vector and the angle between the stator current vector and the rotor flux vector remain unchanged, then Formula Six can be obtained: Substituting Formula 5 and Formula 6 into Formula 4, we obtain Formula 7: 。 7. The instantaneous power control method for a sensorless permanent magnet synchronous generator according to claim 6, characterized in that, Instantaneous power is a function of speed, stator current amplitude, and stator current phase. When the stator current amplitude is constant and the angle between the stator current and the rotor flux vector is 90 degrees, the instantaneous active power reaches its maximum value, while the instantaneous reactive power reaches its minimum value. At this time, the active power and reactive power can be expressed by Formula 8: In the dq coordinate system, the relationship between the magnitude and phase angle of the quadrature and direct axis currents and the stator current vectors can be expressed by Equation Nine: Substituting Formula 9 into Formula 7, we obtain Formula 10: 。 8. The instantaneous power control method for a sensorless permanent magnet synchronous generator according to claim 7, characterized in that, Formula 10 can be used for instantaneous power detection. When the reactive power is at its minimum, the system operates at unity power factor. Formula 10 shows that the reactive power is divided into two parts: one part is the reactive power acting on the stator inductor, and the other part is the reactive power exchanged between the rotor flux linkage and the stator flux linkage. When the reactive power acting on the stator inductor is at its minimum, the reactive power can be minimized by controlling the direct-axis current. Therefore, the difference in rated instantaneous reactive power can be expressed as Formula 11: When the system is in steady state, Equation 11 is 0.

9. The permanent magnet synchronous generator control system according to claim 1, characterized in that, The back electromotive force of the permanent magnet synchronous generator is estimated using a sliding mode observer, and then the precise rotor angular position and angular velocity are obtained through a phase-locked loop; the state equation of the permanent magnet synchronous generator in the two-phase stationary α-β coordinate system can be expressed as Equation Twelve: According to sliding mode observer theory, the mathematical model of the current observer in the α-β coordinate system can be expressed as Equation Thirteen: In the formula and It is an estimated value of the stator current in the α-β coordinate system. and It is an estimate of the back electromotive force in the α-β coordinate system, z α and z β It is a control function, which uses a saturation function, and can be expressed as Formula Fourteen: In the formula, k is the back electromotive force of the permanent magnet synchronous generator, while the current difference is defined as the sliding surface, as shown in Formula 15: Therefore, the relationship between the saturation function and the sliding surface can be transformed into Formula Sixteen: In the formula, Δ represents the boundary layer. The current error signal when the system is stable contains back EMF information. By passing through a low-pass filter, the back EMF can be obtained as shown in Formula 17. Where ω c It is the resonant frequency of the low-pass filter.

10. The permanent magnet synchronous generator control system according to claim 9, characterized in that, The coordinate transformation is performed using the angle output by the phase-locked loop, converting the observed back electromotive force in the α-β coordinate system into a back electromotive force component in the dq coordinate system. By using a PI controller to control the d-axis component of the back electromotive force to be 0, the angular velocity information can be obtained. After integration, the angular position can be obtained.

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