Method and system for output voltage balance control of double-winding induction motor generating system

Abstract

This invention provides a method and system for output voltage balance control in a dual-winding induction motor power generation system, aiming to solve the problem of low output voltage balance caused by uncertain and asymmetrical load disturbances in aircraft variable frequency AC power generation systems. It belongs to the technical field of variable frequency AC power generation. This invention achieves active suppression of output voltage imbalance, improving power supply quality. It can estimate and compensate for unbalanced voltage on the power winding side in real time, thereby effectively suppressing output voltage imbalance, ensuring the symmetry and stability of the three-phase voltage, and improving the power quality of the dual-winding induction motor power generation system. It decomposes the three-phase unbalanced voltage into positive-sequence and negative-sequence components, and uses an orthogonal signal acquisition device to accurately separate the negative-sequence component in the power winding side voltage in real time, judging the voltage imbalance by the magnitude of the negative-sequence voltage. This invention can be used in independent power supply applications such as aircraft and ships, and has high versatility.

Description

Technical Field

[0001] This invention relates to the technical field of variable frequency AC power generation, specifically to a method and system for output voltage balance control of a dual-winding induction motor power generation system. Background Technology

[0002] Variable frequency AC power systems represent the current development trend of power systems for multi-electric / all-electric aircraft. These systems primarily utilize variable frequency AC power while also incorporating DC buses to meet the diverse electrical load requirements of the aircraft. However, with the increasing electrification of aircraft, the power consumption of multi-electric aircraft is growing, and the types of loads are becoming more numerous. These loads exhibit imbalance and asymmetry, severely impacting the stability of the power generation system.

[0003] Dual-winding induction motors are a new type of induction motor that emerged at the beginning of this century. They inherit the core advantages of traditional single-winding induction motors, such as brushless squirrel-cage rotors, simple and robust structure, and high operational reliability. At the same time, they overcome the shortcomings of traditional models, such as large converter capacity requirements, lag in excitation regulation response, and easy degradation of power quality under unbalanced operating conditions. In independent operating scenarios such as ships and aircraft, load imbalance is common. Unbalanced loads can cause negative-sequence components in the motor output voltage, leading to increased equipment vibration and noise, accelerated insulation aging, and other problems. Therefore, negative-sequence voltage suppression technology has become a research focus. Tennessee Institute of Technology (TITEK) and Aalborg University (Aalborg University) have focused on the problem of unbalanced load adaptation in wind power generation. The Indian Institute of Technology (IIT) has accumulated relevant achievements in negative-sequence suppression for independent power systems on ships. Nanjing University of Aeronautics and Astronautics has conducted special research on the load adaptability of dual-winding induction motor power generation systems. Chongqing University, Naval University of Engineering, and Qingdao University have also explored negative-sequence suppression schemes in the field of special power supplies. The core feature of a dual-winding induction motor lies in the two independent windings with the same number of pole pairs on the stator: one is the power winding, directly connected to the load to achieve power output; the other is the control winding, connected to the control circuit via a converter to handle excitation regulation and power quality optimization. The two windings are electrically completely isolated, achieving energy coupling only through the air gap magnetic field. This provides an advantage in suppressing negative sequence voltage under unbalanced loads. The positive and negative sequence components of the magnetic field can be adjusted in real time via the control winding, quickly compensating for magnetic field distortion caused by unbalanced loads without complex modifications to the power winding circuit. This effectively suppresses negative sequence voltage and provides structural support for high-quality power output.

[0004] Whether it's variable frequency AC power generation or AC / DC hybrid power generation, relevant technical standards clearly define the dynamic performance of DC and AC voltages. However, unbalanced loads introduce negative sequence voltage and current, increasing the generator's negative sequence impedance at high speeds and further amplifying the imbalance of the three-phase AC output voltage. To address the harmonics and imbalances caused by different loads, it's often necessary to add power quality compensation devices to the downstream system or damping windings to the generator rotor to improve the harmonic content and imbalance of the output voltage. However, these methods increase the complexity of the power supply system, reduce energy utilization, and have limited ability to improve power quality. Current research indicates that the applied dual-winding induction motor power generation technology does not consider the impact of load imbalance on the dynamic performance of the generated voltage, resulting in voltage imbalance. To address this issue, there is currently limited research on control methods for dual-winding induction motor power generation systems with unbalanced loads. Summary of the Invention

[0005] This invention is made to solve the above-mentioned problems, and its purpose is to provide a method and system for output voltage balance control of a dual-winding induction motor power generation system.

[0006] This invention provides a method for output voltage balance control of a dual-winding induction motor power generation system, characterized by the following steps: S1: Acquire the DC bus voltage of the control winding and the three-phase voltage of the power winding side of the dual-winding induction motor, and perform coordinate transformation to obtain the voltage components of the power winding in both the stationary and synchronously rotating coordinate systems; S2: Acquire the three-phase current of the control winding side of the dual-winding induction motor to obtain the current components of the control winding in the stationary coordinate system; S3: Construct a power winding voltage phase frequency lock-in device and a control winding voltage phase frequency lock-in device for the dual-winding induction motor. A current phase-frequency lockout is used to lock the output voltage on the power winding side and the three-phase current on the control winding side, obtaining the frequency and phase of the output voltage of the power winding and the frequency and phase of the current of the control winding in a synchronous rotating coordinate system; S4: When a three-phase unbalanced load is installed on the power winding side, the positive and negative sequence of the three-phase unbalanced voltage output on the power winding side is separated, and its positive and negative sequence voltage components are extracted; S5: The positive and negative sequence of the three-phase unbalanced current on the control winding side is separated, and its positive and negative sequence current components are extracted. S6: Calculate the effective value of the positive-sequence voltage of the power winding based on the positive-sequence voltage component on the power winding side. Construct a controller for the effective value of the positive-sequence voltage of the power winding based on the error feedback between the effective value and the given value, and obtain the given value of the d-axis component of the positive-sequence current of the control winding. S7: Construct a DC bus voltage controller based on the error feedback between the collected DC bus voltage of the control winding and the given value, and obtain the given value of the q-axis component of the positive-sequence current of the control winding. S8: Construct a negative-sequence voltage suppressor based on the error feedback between the negative-sequence voltage component and the given value on the power winding side. The negative sequence current components of the control winding current α-axis and β-axis are obtained respectively, and the two negative sequence current component values ​​are unified into the positive sequence rotating coordinate system through the control winding current phase frequency locker; S9: A current compensation controller for the composite positive and negative sequence current components is constructed in the positive sequence rotating coordinate system. The given value of the composite positive and negative sequence voltage components of the control winding is obtained through error feedback and voltage compensation. The drive signal is generated by space vector modulation to drive the inverter switching tube and control the output voltage of the dual-winding induction motor to stabilize when it is equipped with a three-phase unbalanced load.

[0007] The output voltage balance control method for a dual-winding induction motor power generation system provided by this invention may also have the following feature: In step S3, the method for obtaining the frequency and phase of the output voltage of the power winding and the frequency and phase of the current of the control winding in the synchronous rotating coordinate system is as follows:

[0008] The output voltage on the power winding side is controlled by a phase frequency lock-in device. , , Three-phase current on the control winding side , , The frequency and phase of the input signal are locked, and the output is adjusted through error feedback to keep the frequency and phase of the output signal synchronized with those of the input signal. The resonant frequency and phase of the input signal are obtained, and the frequency of the output voltage is obtained using formula (1). and phase and the frequency of the current in the control winding and phase :

[0009] (1)

[0010] in, It is the output voltage on the power winding side. , , After transformation Voltage value in coordinate system It controls the three-phase current on the winding side. , , After transformation Voltage value in coordinate system, K d K is the phase-locked loop gain coefficient. c It is the phase lock proportional coefficient, K f These are the phase-locked filter parameters, where τ is the time constant of the phase-locked circuit. Represents the integral operator.

[0011] The output voltage balance control method for a dual-winding induction motor generator system provided by this invention may also have the following feature: In step S4, the method for extracting the positive-sequence voltage component and the negative-sequence voltage component of the three-phase unbalanced voltage is as follows:

[0012] Construct a set of phasors and :

[0013] (2)

[0014] in, It is a phasor and coefficient, It is the frequency of the output voltage of the power winding of a dual-winding induction motor, where e is the base of the natural logarithm.

[0015] By locking the output voltage frequency in S3, And the voltage on the power winding side is obtained according to formula (3). , Positive sequence components in the stationary coordinate system , and negative order components , :

[0016] (3).

[0017] The output voltage balance control method for a dual-winding induction motor generator system provided by this invention may also have the following feature: In step S5, the method for extracting the positive-sequence current component and the negative-sequence current component of the three-phase unbalanced current is as follows:

[0018] Construct a set of phasors and :

[0019] (4)

[0020] in, It is a phasor and coefficient, It refers to the frequency of the three-phase current in the control winding of a dual-winding induction motor.

[0021] By locking the frequency of the three-phase current in S3, The phase-frequency lockout can achieve the control of the actual frequency. The sinusoidal signal has no steady-state error tracking, and the current on the control winding side is obtained according to formula (5). Positive sequence components in the stationary coordinate system and negative order components : (5).

[0022] The output voltage balance control method for a dual-winding induction motor generator system provided by this invention may also have the following feature: In step S6, the method for obtaining the given value of the d-axis component of the control winding positive sequence current is as follows:

[0023] Using the positive sequence voltage component extracted from the power winding side in S4, the effective value of the positive sequence voltage of the power winding is calculated. The effective value of the positive sequence voltage of the power winding is then compared with a given value. The error feedback is used to construct a power winding positive sequence voltage RMS controller, which obtains the setpoint of the positive sequence current d-axis component of the control winding current in the positive reference frame. :

[0024] (6)

[0025] Among them, K p K is the proportional parameter of the power winding positive sequence voltage controller. i These are the integral parameters for the positive sequence voltage controller of the power winding.

[0026] The output voltage balance control method for a dual-winding induction motor power generation system provided by this invention may also have the following feature: In step S7, the method for obtaining the given value of the q-axis component of the control winding positive sequence current is as follows:

[0027] Based on the collected DC bus voltage of the control winding With a given value The error feedback is used to construct a DC bus voltage controller, and the positive sequence current q-axis component of the control winding current in the positive reference frame is obtained as a given value. :

[0028] (7)

[0029] Among them, C p C is the proportional coefficient of the DC bus voltage controller. i This represents the integral coefficient of the DC bus voltage controller.

[0030] The output voltage balance control method for a dual-winding induction motor generator system provided by this invention may also have the following feature: wherein, in S8, the negative sequence current component of the control winding current α axis is given a value. and the given value of the negative sequence current component along the β axis The method for obtaining it is as follows:

[0031] Based on the negative sequence component of the power winding voltage in the stationary coordinate system obtained from S4, the given voltage value is set to 0 by the output voltage controller, and the given values ​​of the negative sequence current components of the control winding current α-axis and β-axis are obtained using formula (8). , :

[0032] (8)

[0033] in, It is the gain coefficient of the output voltage controller. It is the cutoff frequency of the controller.

[0034] The output voltage balance control method for a dual-winding induction motor generator system provided by this invention may also have the following feature: In step S8, the method for unifying the given values ​​of the two negative-sequence current components to the positive-sequence rotating coordinate system by controlling the winding current phase frequency lock is as follows:

[0035] Based on the phase angle of the control winding current obtained from the phase frequency lock in S3, the negative sequence current components of the control winding current along the α and β axes are unified into the positive sequence rotating coordinate system using formula (9) to obtain the following result. , , represented as:

[0036] (9)

[0037] in, , This is the given value of the negative sequence current component on the dq axis in the negative sequence rotating coordinate system.

[0038] The output voltage balance control method for a dual-winding induction motor power generation system provided by this invention may also have the following feature: wherein, in S9, the composite components of the positive and negative sequence voltages of the control winding are... , The method for obtaining the given value is as follows:

[0039] Based on the given values ​​of the positive and negative sequence current components of the control winding obtained in S6, S7, and S8, a composite current compensation controller is constructed. Using error feedback and voltage compensation, the voltage setpoint of the composite positive and negative sequence voltage components is calculated using formula (10):

[0040] (10)

[0041] in, , and , These are the control winding currents in the positive sequence rotating coordinate system. Axial components and negative sequence Axial components, It is the gain coefficient of the output current compensation controller. Controlling the inductance of the winding, It is a magnetizing inductor. These are the motor inductance parameters; It is the rotor time constant. It is rotor flux linkage.

[0042] This invention also provides an output voltage balance control system for a dual-winding induction motor power generation system, characterized by: an AC voltage acquisition and DC voltage acquisition module: acquiring the DC bus voltage of the control winding and the three-phase voltage of the power winding side of the dual-winding induction motor, and performing coordinate transformation to obtain the voltage component of the power winding in a stationary coordinate system; a current acquisition module: acquiring the three-phase current of the control winding side of the dual-winding induction motor to obtain the current component of the control winding in a stationary coordinate system; and a voltage and current frequency locking module: constructing a power winding voltage phase frequency lock and a control winding current phase frequency lock for the dual-winding induction motor to balance the output voltage and current of the power winding. The output voltage on the power winding side and the three-phase current on the control winding side are phase-frequency locked to obtain the frequency and phase of the output voltage of the power winding and the frequency and phase of the current of the control winding in a synchronous rotating coordinate system; Three-phase unbalanced voltage positive and negative sequence separation and extraction module: when a three-phase unbalanced load is installed on the power winding side, the positive and negative sequence of the three-phase unbalanced voltage output on the power winding side are separated, and the positive and negative sequence voltage components are extracted; Three-phase unbalanced current positive and negative sequence separation and extraction module: the positive and negative sequence of the three-phase unbalanced current on the control winding side are separated, and the positive and negative sequence current components are extracted; Power winding AC The following modules are defined as follows: Positive Sequence Voltage RMS Control Module: Calculates the RMS value of the positive sequence voltage of the power winding based on the positive sequence component of the voltage on the power winding side. It then constructs a positive sequence voltage RMS controller based on the error feedback between the RMS value and the given value, obtaining the given value of the d-axis component of the positive sequence current of the control winding. DC Bus Voltage Control Module: Constructs a DC bus voltage controller based on the error feedback between the acquired DC bus voltage and the given value of the control winding, obtaining the given value of the q-axis component of the positive sequence current of the control winding. Negative Sequence Voltage Suppression Module: Constructs a negative sequence voltage suppression module based on the error feedback between the negative sequence voltage component and the given value of the power winding side. A negative sequence voltage suppressor is constructed to obtain the given values ​​of the negative sequence current components of the control winding current along the α and β axes, respectively. The two negative sequence current component given values ​​are then unified into the positive sequence rotating coordinate system through a control winding current phase frequency lock. The control winding current composite compensation control and drive module constructs a current compensation controller that combines the positive and negative sequence current components in the positive sequence rotating coordinate system. The given values ​​of the composite components of the positive and negative sequence voltages of the control winding are obtained through error feedback and voltage compensation. Space vector modulation is used to generate drive signals to drive the inverter switching transistors, thereby stabilizing the output voltage of the dual-winding induction motor when it is equipped with a three-phase unbalanced load.

[0043] Compared with the prior art, the present invention has the following advantages:

[0044] This invention achieves active suppression of output voltage imbalance, improving power supply quality. It can estimate and compensate for unbalanced voltage on the power winding side in real time, effectively suppressing output voltage imbalance, ensuring the symmetry and stability of the three-phase voltage, and improving the power quality of a dual-winding induction motor generator system. The invention decomposes the three-phase unbalanced voltage into positive-sequence and negative-sequence components, and uses a quadrature signal acquisition unit to accurately separate the negative-sequence component in the power winding side voltage in real time, determining the voltage imbalance based on the magnitude of the negative-sequence voltage. This invention is applicable to independent power supply applications such as aircraft and ships, demonstrating high versatility.

[0045] The method of the present invention uses a phase lock-in device to adaptively lock the positive sequence voltage component, ensuring that the control structure can still maintain an accurate synchronous coordinate system reference when the frequency fluctuates due to load changes, thereby giving the method of the present invention good load adaptability. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of a dual-winding induction motor power generation system in an embodiment of the present invention.

[0047] Figure 2 This is a flowchart of the output voltage balance control method of a dual-winding induction motor power generation system in an embodiment of the present invention.

[0048] Figure 3 This is a schematic flowchart illustrating the overall architecture of the output voltage balance control method for a dual-winding induction motor power generation system in an embodiment of the present invention.

[0049] Explanation of symbols for main components:

[0050] In the diagram: 1. Dual-winding induction motor unit; 2. Generator drive unit; 3. Three-phase filter inductor; 4. Three-phase excitation capacitor; 5. DC power grid; 6. AC power grid; 7. AC current sensor; 8. DC voltage sensor; 9. AC voltage sensor; 10. Drive circuit; 11. Control circuit; 12. DC bus capacitor. Detailed Implementation

[0051] To make the technical means, creative features, objectives and effects of the present invention easy to understand, the following embodiments, in conjunction with the accompanying drawings, specifically illustrate the output voltage balance control method and system of the dual-winding induction motor power generation system of the present invention.

[0052] The output voltage balance control method for the dual-winding induction motor power generation system in this embodiment includes the following steps:

[0053] Figure 1 This is a schematic diagram of a dual-winding induction motor power generation system in an embodiment of the present invention.

[0054] like Figure 1 As shown, the dual-winding induction motor includes a dual-winding induction motor unit 1, a generator drive unit 2 with output excitation reactive power and active power, a three-phase filter inductor 3, a three-phase excitation capacitor 4, a DC power grid 5, an AC power grid 6, an AC current sensor 7, a DC voltage sensor 8, an AC voltage sensor 9, a drive circuit 10, a control circuit 11, and a DC bus capacitor 12. The DC winding of the dual-winding induction motor unit 1 is connected to the AC output side of the generator drive unit 2 via the three-phase filter inductor 3. The DC bus capacitor 12 is connected in parallel to the DC side of the generator drive unit 2 and is fed into the DC power grid 5. The AC winding of the dual-winding induction motor unit 1 is a three-phase four-wire system, with the three-phase excitation capacitor 4 connected in parallel and fed into the AC power grid 6.

[0055] Figure 2 This is a flowchart of the output voltage balance control method of a dual-winding induction motor power generation system in an embodiment of the present invention. Figure 3 This is a schematic flowchart illustrating the overall architecture of the output voltage balance control method for a dual-winding induction motor power generation system in an embodiment of the present invention.

[0056] like Figures 2-3 As shown, S1: Collects the DC bus voltage of the control winding and the three-phase voltage of the power winding side of the dual-winding induction motor, and performs coordinate transformation to obtain the voltage components of the power winding in the stationary coordinate system, specifically:

[0057] A DC voltage sensor 8 is used to collect the DC bus voltage of the control winding of the dual-winding induction motor, and the square is calculated to obtain the DC bus voltage U. DC 2 The three-phase voltage on the power winding side of the dual-winding induction motor is acquired in real time using an AC voltage sensor 9 to obtain the raw voltage signal on the power winding side. The raw voltage signal is then processed by coordinate transformation to obtain the voltage component u of the AC winding along the α-axis in the stationary coordinate system. pα Voltage component u along the β axis pβ .

[0058] S2: Collect the three-phase current on the control winding side of the dual-winding induction motor to obtain the current components of the control winding in both the stationary and synchronous rotating coordinate systems, specifically:

[0059] A current sensor is used to collect the three-phase current on the control winding side of a dual-winding induction motor. After coordinate transformation, the current component i along the α-axis in the stationary coordinate system is obtained. cα The current component i along the β axis cβ and the current component i along the d-axis in the synchronous rotating coordinate system cd q-axis current component i cq .

[0060] S3: Construct a phase-frequency lockout device for the power winding voltage and a phase-frequency lockout device for the control winding current of a dual-winding induction motor. This device performs phase-frequency locking on the output voltage of the power winding and the three-phase current of the control winding, obtaining the frequency and phase of the power winding output voltage and the control winding current in a synchronous rotating coordinate system. Specifically:

[0061] The output voltage on the power winding side is controlled by a phase frequency lock-in device. , , Three-phase current on the control winding side , , The frequency and phase of the input signal are locked, and the output is adjusted through error feedback to keep the frequency and phase of the output signal synchronized with those of the input signal. The resonant frequency and phase of the input signal are obtained, and the frequency of the output voltage is obtained using formula (1). and phase and the frequency of the current in the control winding and phase :

[0062] (1)

[0063] in, It is the output voltage on the power winding side. , , After transformation Voltage value in coordinate system It controls the three-phase current on the winding side. , , After transformation Voltage value in coordinate system, K d K is the phase-locked loop gain coefficient. c It is the phase lock proportional coefficient, K f These are the phase-locked filter parameters, where τ is the time constant of the phase-locked circuit. Represents the integral operator.

[0064] S4: When a three-phase unbalanced load is connected to the power winding side, the positive and negative sequence of the three-phase unbalanced voltage output from the power winding side is separated, and its positive and negative sequence voltage components are extracted, specifically:

[0065] Construct a set of phasors and :

[0066] (2)

[0067] in, It is a phasor and coefficient, It is the frequency of the output voltage of the power winding of a dual-winding induction motor, where e is the base of the natural logarithm.

[0068] By locking the output voltage frequency in S3, The phase-frequency lockout can achieve the control of the actual frequency. The sinusoidal signal is tracked without steady-state error, and the voltage on the power winding side is obtained according to formula (3). , Positive sequence components in the stationary coordinate system , and negative order components , :

[0069] (3).

[0070] S5: Separate the positive and negative sequence currents of the three-phase unbalanced current on the control winding side, and extract the positive and negative sequence current components, specifically:

[0071] Construct a set of phasors and :

[0072] (4)

[0073] in, It is a phasor and coefficient, It is the frequency of the three-phase current in the control winding of a dual-winding induction motor.

[0074] By locking the frequency of the three-phase current in S3, The phase-frequency lockout can achieve the control of the actual frequency. The sinusoidal signal has no steady-state error tracking, and the current on the control winding side is obtained according to formula (5). , Positive sequence components in the stationary coordinate system , and negative order components , :

[0075] (5)

[0076] S6: Calculate the effective value of the positive sequence voltage of the power winding based on the positive sequence component of the voltage on the power winding side, and compare the effective value of the positive sequence voltage of the power winding with the given value. The error feedback is used to construct a power winding positive sequence voltage RMS controller, which obtains the setpoint of the positive sequence current d-axis component of the control winding current in the positive reference frame. Specifically:

[0077] Using the positive sequence voltage component extracted from the power winding side in S4, the effective value of the positive sequence voltage of the power winding is calculated. The effective value of the positive sequence voltage of the power winding is then compared with a given value. The error feedback is used to construct a power winding positive sequence voltage RMS controller, which obtains the setpoint of the positive sequence current d-axis component of the control winding current in the positive reference frame. :

[0078] (6)

[0079] Among them, K p K is the proportional parameter of the power winding positive sequence voltage controller. i These are the integral parameters for the positive sequence voltage controller of the power winding.

[0080] S7: Based on the collected DC bus voltage of the control winding With a given value The error feedback is used to construct a DC bus voltage controller, and the given value of the positive sequence current q-axis component of the control winding current in the positive reference frame is obtained, specifically:

[0081] Based on the collected DC bus voltage of the control winding With a given value The error feedback is used to construct a DC bus voltage controller, and the positive sequence current q-axis component of the control winding current in the positive reference frame is obtained as a given value. :

[0082] (7)

[0083] Among them, C p C is the proportional coefficient of the DC bus voltage controller. i This represents the integral coefficient of the DC bus voltage controller.

[0084] S8: Based on the error feedback between the negative sequence voltage component on the power winding side and the given value, a negative sequence voltage suppressor is constructed to obtain the given values ​​of the negative sequence current components on the α-axis and β-axis of the control winding current, respectively. and The two negative sequence current components are then unified to the positive sequence rotating coordinate system via a control winding current phase frequency lock, specifically as follows:

[0085] Based on the negative sequence component of the power winding voltage in the stationary coordinate system obtained from S4, the given voltage value is set to 0. Through the output voltage controller, the given values ​​of the negative sequence current components of the control winding current α-axis and β-axis are obtained using formula (8). , :

[0086] (8)

[0087] in, It is the gain coefficient of the output voltage controller. It is the cutoff frequency of the controller.

[0088] Based on the phase angle of the control winding current obtained from the phase frequency lock in S3, the negative sequence current components of the control winding current along the α and β axes are unified into the positive sequence rotating coordinate system using formula (9) to obtain the following result. , , represented as:

[0089] (9)

[0090] in, , This is the given value of the negative sequence current component on the dq axis in the negative sequence rotating coordinate system.

[0091] S9: A current compensation controller is constructed in the positive-sequence rotating coordinate system to combine the positive-sequence and negative-sequence current components. The given value of the composite positive-sequence and negative-sequence voltage components of the control winding is obtained through error feedback and voltage compensation. Space vector modulation is used to generate a drive signal to drive the inverter switching transistors, thereby stabilizing the output voltage of the dual-winding induction motor when it is equipped with a three-phase unbalanced load. Specifically:

[0092] Based on the given values ​​of the positive and negative sequence current components of the control winding obtained in S6, S7, and S8, a composite current compensation controller is constructed. Based on error feedback and voltage compensation, the composite components of the positive and negative sequence voltages are calculated using formula (10). , Voltage setpoint:

[0093] (10)

[0094] in, , and , These are the control winding currents in the positive sequence rotating coordinate system. Axial components and negative sequence Axial components, It is the gain coefficient of the output current compensation controller. Controlling the inductance of the winding, It is a magnetizing inductor. These are the motor inductance parameters; It is the rotor time constant. It is rotor flux linkage.

[0095] The obtained voltage setpoint is transformed inversely to generate the control winding voltage setpoint in the stationary coordinate system. and The signal is sent to the control vector modulation driver to generate a drive signal to drive the inverter switching transistor, thereby controlling the output voltage of the dual-winding induction motor to stabilize when it is equipped with a three-phase unbalanced load.

[0096] This embodiment also provides an output voltage balance control system for a dual-winding induction motor power generation system, including:

[0097] The AC voltage acquisition and DC voltage acquisition module is used to implement S1, namely: to acquire the DC bus voltage of the control winding and the three-phase voltage of the power winding side of the dual-winding induction motor, and to perform coordinate transformation to obtain the voltage components of the power winding in the stationary coordinate system.

[0098] The current acquisition module is used to implement S2, that is: to acquire the three-phase current on the control winding side of the dual-winding induction motor and obtain the current components of the control winding in the stationary coordinate system and the synchronous rotating coordinate system.

[0099] The voltage and current frequency locking module is used to implement S3, namely: to construct a power winding voltage phase frequency lock and a control winding current phase frequency lock for a dual-winding induction motor, to lock the output voltage on the power winding side and the three-phase current on the control winding side, and to obtain the frequency and phase of the output voltage of the power winding and the frequency and phase of the current of the control winding in the synchronous rotating coordinate system.

[0100] The three-phase unbalanced voltage positive and negative sequence separation and extraction module is used to implement S4, that is: when a three-phase unbalanced load is connected on the power winding side, the positive and negative sequence of the three-phase unbalanced voltage output on the power winding side is separated and its positive and negative sequence voltage components are extracted.

[0101] The three-phase unbalanced current positive and negative sequence separation and extraction module is used to implement S5, that is: to separate the positive and negative sequence of the three-phase unbalanced current on the control winding side and extract its positive sequence current component and negative sequence current component.

[0102] The power winding AC voltage positive sequence effective value control module is used to implement S6, that is: calculate the effective value of the power winding positive sequence voltage based on the voltage positive sequence component on the power winding side, construct the power winding positive sequence voltage effective value controller through error feedback between the power winding positive sequence voltage effective value and the given value, and obtain the given value of the d-axis component of the control winding positive sequence current;

[0103] The control winding DC bus voltage control module is used to implement S7, that is: to construct a DC bus voltage controller based on the error feedback between the collected control winding DC bus voltage and the given value, and to obtain the given value of the q-axis component of the positive sequence current of the control winding;

[0104] The power winding negative sequence voltage suppression module is used to implement S8, that is: based on the error feedback between the negative sequence voltage component on the power winding side and the given value, a negative sequence voltage suppressor is constructed to obtain the given values ​​of the negative sequence current components of the control winding current α axis and β axis respectively, and the two negative sequence current component given values ​​are unified to the positive sequence rotating coordinate system through the control winding current phase frequency locker.

[0105] The control winding current composite compensation control and drive module is used to implement S9, namely: constructing a current compensation controller that combines positive and negative sequence current components in a positive sequence rotating coordinate system, obtaining the given value of the composite components of positive and negative sequence voltage of the control winding through error feedback and voltage compensation, using space vector modulation to generate drive signals to drive the inverter switching transistors, and controlling the output voltage of the dual-winding induction motor to be stable when equipped with a three-phase unbalanced load.

[0106] The role and effect of the embodiments

[0107] The output voltage balance control method and system for a dual-winding induction motor power generation system according to the present invention have the following beneficial effects:

[0108] This invention achieves active suppression of output voltage imbalance, improving power supply quality. It can estimate and compensate for unbalanced voltage on the power winding side in real time, effectively suppressing output voltage imbalance, ensuring the symmetry and stability of the three-phase voltage, and improving the power quality of a dual-winding induction motor generator system. The invention decomposes the three-phase unbalanced voltage into positive-sequence and negative-sequence components, and uses a quadrature signal acquisition unit to accurately separate the negative-sequence component in the power winding side voltage in real time, determining the voltage imbalance based on the magnitude of the negative-sequence voltage. This invention is applicable to independent power supply applications such as aircraft and ships, demonstrating high versatility.

[0109] The method of the present invention uses a phase lock-in device to adaptively lock the positive sequence voltage component, ensuring that the control structure can still maintain an accurate synchronous coordinate system reference when the frequency fluctuates due to load changes, thereby giving the method of the present invention good load adaptability.

[0110] The method of this invention features simple parameter tuning, low model dependence, strong anti-interference capability, and no complex algorithms, making it easier to implement in experiments. It can also suppress negative-sequence voltage asymmetry caused by different loads. In this control strategy, the controller parameters are designed relatively independently and are easy to adjust. The final drive signal is generated through space vector modulation, which is easy to implement in a digital controller and has strong engineering applicability.

[0111] This invention utilizes the inherent structural characteristics of a dual-winding induction motor, with all control algorithms implemented through a power converter on the control winding side. No additional compensation device is required on the power winding output side, nor is any special modification to the generator rotor necessary. This simplifies the overall structure of the dual-winding induction motor, reduces hardware costs, and improves overall reliability.

[0112] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for output voltage balance control of a dual-winding induction motor generator system, characterized in that, Includes the following steps: S1: Collect the DC bus voltage of the control winding and the three-phase voltage of the power winding side of the dual-winding induction motor, and perform coordinate transformation to obtain the voltage components of the power winding in the stationary coordinate system. S2: Collect the three-phase current on the control winding side of the dual-winding induction motor to obtain the current components of the control winding in the stationary coordinate system and the synchronous rotating coordinate system; S3: Construct the power winding voltage phase frequency lock and the control winding current phase frequency lock of the dual-winding induction motor, perform phase frequency lock on the output voltage of the power winding side and the three-phase current of the control winding side, and obtain the frequency and phase of the output voltage of the power winding and the frequency and phase of the current of the control winding in the synchronous rotating coordinate system. S4: When a three-phase unbalanced load is installed on the power winding side, the positive and negative sequence of the three-phase unbalanced voltage output from the power winding side is separated, and its positive sequence voltage component and negative sequence voltage component are extracted. S5: Separate the positive and negative sequence of the three-phase unbalanced current on the control winding side and extract its positive sequence current component and negative sequence current component. S6: Calculate the positive sequence voltage amplitude of the power winding based on the positive sequence voltage component of the power winding side, and construct a positive sequence voltage amplitude controller for the power winding through error feedback between the positive sequence voltage amplitude of the power winding and the given value, so as to obtain the given value of the d-axis component of the positive sequence current of the control winding. S7: Construct a DC bus voltage controller based on the error feedback between the square of the collected control winding DC bus voltage and the given value, and obtain the given value of the q-axis component of the positive sequence current of the control winding; S8: Based on the error feedback between the negative sequence voltage component and the given value on the power winding side, a negative sequence voltage suppressor is constructed to obtain the given values ​​of the negative sequence current components on the α-axis and β-axis of the control winding current, and the two given values ​​of the negative sequence current components are unified to the positive sequence rotating coordinate system through the control winding current phase frequency locker. S9: A current compensation controller is constructed in the positive-sequence rotating coordinate system to combine the positive-sequence and negative-sequence current components. The given value of the composite component of the positive-sequence and negative-sequence voltage of the control winding is obtained through error feedback and voltage compensation. Space vector modulation is used to generate a drive signal to drive the inverter switching transistors, thereby controlling the output voltage of the dual-winding induction motor to stabilize when it is equipped with the three-phase unbalanced load. In step S4, the method for extracting the positive-sequence voltage component and the negative-sequence voltage component of the three-phase unbalanced voltage is as follows: Construct a set of phasors and : （2） in, It is a phasor and coefficient, It is the frequency of the output voltage of the power winding of a dual-winding induction motor, where e is the base of the natural logarithm. By locking the output voltage frequency in S3, and using vectors and The positive-sequence and negative-sequence voltage components of the power winding side in the stationary coordinate system were calculated. In step S9, the method for obtaining the given value of the composite component of the positive-sequence and negative-sequence voltages of the control winding is as follows: Based on the given values ​​of the positive and negative sequence current components of the control winding obtained in S6, S7, and S8, a composite current compensation controller is constructed. Based on error feedback and voltage compensation, the composite components of the positive and negative sequence voltages are calculated using formula (10). , Voltage setpoint: （10） in, and These are the setpoints for the positive sequence current d-axis component and q-axis component in the positive reference frame, respectively. , This is obtained by unifying the negative sequence current components of the control winding current along the α and β axes into a positive sequence rotating coordinate system. , and , These are the control winding currents in the positive sequence rotating coordinate system. Axial components and negative sequence Axial components, It is the gain coefficient of the output current compensation controller. Controlling the inductance of the winding, It is a magnetizing inductor. These are the motor inductance parameters; It is the rotor time constant. It is rotor flux linkage. It is the controller's cutoff frequency. It is the frequency of the three-phase current in the control winding of a dual-winding induction motor.

2. The output voltage balance control method for a dual-winding induction motor generator system according to claim 1, characterized in that: in, In S3, the method for obtaining the frequency and phase of the output voltage of the power winding and the frequency and phase of the current of the control winding in the synchronous rotating coordinate system is as follows: The output voltage on the power winding side is controlled by a phase frequency lock-in device. , , Three-phase current on the control winding side , , The frequency and phase of the input signal are locked, and the output is adjusted through error feedback to keep the frequency and phase of the output signal synchronized with those of the input signal. The resonant frequency and phase of the input signal are obtained, and the frequency of the output voltage is obtained using formula (1). and phase and the frequency of the current in the control winding and phase : （1） in, It is the output voltage on the power winding side. , , After transformation Voltage value in coordinate system It controls the three-phase current on the winding side. , , After transformation Voltage value in coordinate system, K d K is the phase-locked loop gain coefficient. c It is the phase lock proportional coefficient, K f These are the phase-locked filter parameters, where τ is the time constant of the phase-locked circuit. Represents the integral operator.

3. The output voltage balance control method for a dual-winding induction motor generator system according to claim 2, characterized in that: in, In step S4, the method for extracting the positive-sequence voltage component and the negative-sequence voltage component of the three-phase unbalanced voltage is as follows: Construct a set of phasors and : （2） in, It is a phasor and coefficient, It is the frequency of the output voltage of the power winding of a dual-winding induction motor, where e is the base of the natural logarithm. By locking the output voltage frequency in S3, And the voltage on the power winding side is obtained according to formula (3). , Positive sequence components in the stationary coordinate system , and negative order components , : （3）。 4. The output voltage balance control method for a dual-winding induction motor generator system according to claim 2, characterized in that: in, In step S5, the method for extracting the positive-sequence current component and the negative-sequence current component of the three-phase unbalanced current is as follows: Construct a set of phasors and : （4） in, It is a phasor and coefficient, It refers to the frequency of the three-phase current in the control winding of a dual-winding induction motor. By locking the frequency of the three-phase current in S3, The phase-frequency lockout can achieve the control of the actual frequency. The sinusoidal signal has no steady-state error tracking, and the current on the control winding side is obtained according to formula (5). Positive sequence components in the stationary coordinate system and negative order components : (5).

5. The output voltage balance control method for a dual-winding induction motor generator system according to claim 3, characterized in that: in, In step S6, the method for obtaining the given value of the d-axis component of the positive sequence current of the control winding is as follows: Using the positive-sequence voltage component extracted from the power winding side in S4, the magnitude of the positive-sequence voltage of the power winding is calculated. The magnitude of the positive-sequence voltage of the power winding is then compared with a given value. Error feedback is used to construct a power winding positive sequence voltage amplitude controller, and the given value of the positive sequence current d-axis component of the control winding current in the positive reference frame is obtained. : （6） Among them, K p K is the proportional parameter of the power winding positive sequence voltage controller. i These are the integral parameters for the positive sequence voltage controller of the power winding.

6. The output voltage balance control method for a dual-winding induction motor generator system according to claim 5, characterized in that: in, In step S7, the method for obtaining the given value of the q-axis component of the positive sequence current of the control winding is as follows: Based on the square of the collected control winding DC bus voltage With a given value The error feedback is used to construct a DC bus voltage controller, and the positive sequence current q-axis component of the control winding current in the positive reference frame is obtained as a given value. : （7） Among them, C p C is the proportional coefficient of the DC bus voltage controller. i This represents the integral coefficient of the DC bus voltage controller.

7. The output voltage balance control method for a dual-winding induction motor generator system according to claim 6, characterized in that: in, In S8, the setpoint of the negative sequence current component of the control winding current α axis is... and the given value of the negative sequence current component along the β axis The method for obtaining it is as follows: Based on the negative sequence component of the power winding voltage in the stationary coordinate system obtained from S4, the given voltage value is set to 0 by the output voltage controller, and the given values ​​of the negative sequence current components of the control winding current α-axis and β-axis are obtained using formula (8). , : （8） in, It is the gain coefficient of the output voltage controller. It is the cutoff frequency of the controller.

8. The output voltage balance control method for a dual-winding induction motor generator system according to claim 7, characterized in that: in, In step S8, the method for unifying the two negative sequence current component values ​​to the positive sequence rotating coordinate system through the control winding current phase frequency lock is as follows: Based on the phase angle of the control winding current obtained from the phase frequency lock in S3, the negative sequence current components of the control winding current along the α and β axes are unified to the positive sequence rotating coordinate system using formula (9) to obtain the following result. , , is represented as: ， （9）， in, , This is the given value of the negative sequence current component on the dq axis in the negative sequence rotating coordinate system.

9. A voltage balance control system for a dual-winding induction motor generator system, characterized in that: Based on the output voltage balance control method of the dual-winding induction motor generator system as described in any one of claims 1-8, including: AC voltage acquisition and DC voltage acquisition module: Acquires the DC bus voltage of the control winding and the three-phase voltage of the power winding side of the dual-winding induction motor, and performs coordinate transformation to obtain the voltage components of the power winding in the stationary coordinate system; Current acquisition module: Acquires the three-phase current on the control winding side of the dual-winding induction motor to obtain the current components of the control winding in the stationary coordinate system and the synchronous rotating coordinate system; Voltage and current frequency locking module: Constructs a power winding voltage phase frequency locker and a control winding current phase frequency locker for the dual-winding induction motor, performs phase frequency locking on the output voltage on the power winding side and the three-phase current on the control winding side, and obtains the frequency and phase of the output voltage of the power winding and the frequency and phase of the current of the control winding in the synchronous rotating coordinate system; Three-phase unbalanced voltage positive and negative sequence separation and extraction module: When a three-phase unbalanced load is installed on the power winding side, the positive and negative sequence of the three-phase unbalanced voltage output from the power winding side is separated, and its positive sequence voltage component and negative sequence voltage component are extracted. Three-phase unbalanced current positive and negative sequence separation and extraction module: performs positive and negative sequence separation on the three-phase unbalanced current on the control winding side, and extracts its positive sequence current component and negative sequence current component; Power winding AC voltage positive sequence amplitude control module: calculates the positive sequence voltage amplitude of the power winding based on the voltage positive sequence component on the power winding side, and constructs a power winding positive sequence voltage amplitude controller through error feedback between the power winding positive sequence voltage amplitude and the given value, thereby obtaining the given value of the d-axis component of the control winding positive sequence current; DC bus voltage control module for control winding: Based on the error feedback between the square of the collected DC bus voltage of the control winding and the given value, a DC bus voltage controller is constructed to obtain the given value of the q-axis component of the positive sequence current of the control winding; Power winding negative sequence voltage suppression module: Based on the error feedback between the negative sequence voltage component and the given value on the power winding side, a negative sequence voltage suppressor is constructed to obtain the given values ​​of the negative sequence current components of the control winding current α axis and β axis respectively, and the two given values ​​of the negative sequence current components are unified to the positive sequence rotating coordinate system through the control winding current phase frequency locker. Control winding current composite compensation control and drive module: Construct a current compensation controller that combines positive and negative sequence current components in the positive sequence rotating coordinate system. Obtain the given value of the composite component of positive and negative sequence voltage of the control winding through error feedback and voltage compensation. Use space vector modulation to generate drive signals to drive the inverter switching transistors and control the output voltage of the dual-winding induction motor to be stable when it is equipped with the three-phase unbalanced load.

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