Bus voltage controller for a dc-biased ac motor, power generation method and system

Abstract

The application discloses a bus voltage controller of a direct current bias type alternating current motor, a power generation method and system, and belongs to the field of alternating current motor driving and control, and comprises: a first operation unit, which is used for calculating a bus voltage error fast terminal sliding mode controller, an expression of a sliding surface thereof is and is used for calculating a first component u1 of a torque given value according to a fast terminal sliding mode control law, and calculating a second component u2 of the torque given value according to an exponential type sliding mode approaching law; an extended state observer, an input end of which is used for receiving and is used for calculating a third component z2 of the torque given value; and a second operation unit, which is used for calculating the torque given value T eref According to the application, the bus voltage control precision and dynamic response characteristics of the direct current bias type alternating current motor can be improved, and thus the power generation quality is improved.

Description

Technical Field

[0001] This invention belongs to the field of AC motor drive and control, and more specifically, relates to a bus voltage controller, power generation method and system for a DC biased AC motor. Background Technology

[0002] With the rapid development of more-electric / all-electric aircraft, the performance requirements for airborne power generation systems are gradually increasing. DC power supply systems, with their advantages of high power quality and high reliability, provide ample assurance for the secondary energy systems of more-electric / all-electric aircraft. The type of motor in a DC power supply system largely determines the system's power quality and reliability. DC-biased AC motors, with their doubly salient pole structure and concentrated stator winding structure, are simple and reliable, suitable for high-speed operation and high-temperature working environments, and have received widespread attention both domestically and internationally in recent years.

[0003] The phase inductance of a DC-biased AC motor consists of DC and AC components, and there is no mutual inductance between the windings. Figure 1 This is a typical phase current waveform of a DC-biased AC motor. Injecting an AC component into the motor's phase current generates a stator magnetic field, while injecting a DC bias component generates a rotor magnetic field. The interaction of these two magnetic fields produces electromagnetic torque. By flexibly changing the magnitude of the DC bias component in the phase current, the magnitude of the rotor magnetic field can be adjusted, ensuring the stability of the bus voltage. Therefore, this type of motor is suitable for power generation in DC power supply systems.

[0004] Figure 2 This diagram shows the main circuit structure of a DC-biased AC motor control system. It includes two rectifiers, designated as the first rectifier and the second rectifier. Each rectifier contains six IGBTs. The three-phase outputs of the first rectifier are represented as A1, B1, and C1, which are connected to the input terminals of phases A, B, and C of the DC-biased AC motor, respectively. The three-phase outputs of the second rectifier are represented as A2, B2, and C2, which are connected to the output terminals of phases A, B, and C of the DC-biased AC motor, respectively. When using existing traditional DC generator control strategies, the DC-biased AC motor inputs the bus voltage error signal to a PI controller, which outputs a torque command value. By adjusting the magnitude of the torque command value, the bus voltage is kept stable. This DC generator bus voltage controller has a simple linear structure, but its control accuracy is highly dependent on system parameters, specifically the proportional constant k. p and integration constant k iThese are key parameters of the PI controller, determining the accuracy of PI control. In practical applications, these two parameters need to be calculated based on system parameters such as resistance, inductance, and capacitance. This control method, which is highly dependent on system parameters, can lead to poor dynamic response characteristics of the bus voltage and reduced steady-state control accuracy when the external load of the system changes drastically or the internal parameters of the system deviate. Summary of the Invention

[0005] To address the shortcomings and improvement needs of existing technologies, this invention provides a bus voltage controller, power generation method, and system for a DC-biased AC motor. The purpose is to fully consider the influence of external load changes and internal parameter deviations, design a variable structure sliding mode controller with low parameter dependence and high control accuracy, improve the bus voltage control accuracy and dynamic response characteristics of the DC-biased AC motor, and thus improve the power generation quality.

[0006] To achieve the above objectives, according to one aspect of the present invention, a bus voltage controller for a DC-biased AC motor is provided, comprising:

[0007] The first arithmetic unit has its first input terminal used to receive the square of the bus voltage setpoint. Its second input terminal is used to receive the square of the bus voltage feedback value. It is used for calculation and The difference is used to obtain the bus voltage error e;

[0008] A fast terminal sliding mode controller, whose input is connected to the output of the first arithmetic unit, has the following expression for its sliding surface: It is used to calculate the first component u1 of the torque setpoint according to the sliding surface s and the fast terminal sliding mode control law, and to calculate the second component u2 of the torque setpoint according to the exponential sliding mode approach law;

[0009] An extended state observer, whose input is used to receive the square of the bus voltage feedback value. Its observation equation is It is used to calculate the third component z2 of the torque setpoint;

[0010] And a second arithmetic unit, whose first input is connected to the first output of the fast terminal sliding mode controller, whose second input is connected to the second output of the fast terminal sliding mode controller, and whose third input is connected to the output of the extended state observer, is used to... Calculate the torque setpoint T eref ;

[0011] Where α>1, k1>0, k2>0; sgn represents the sign function; b0=2ω r / C0, where C0 is the rated value of the bus capacitance, ωr z1 represents the mechanical angular velocity of the motor; z2 represents the square of the bus voltage feedback value. The observed value, z2 represents the sum of internal and external disturbances f of the system. all The observed values, where u represents the system input and e1 represents... The observation error, β1 and β2 are positive coefficients.

[0012] Furthermore, in the fast terminal sliding mode controller, the rate of change of the sliding surface s is:

[0013]

[0014] Where k>0, β>0.

[0015] Furthermore, u1 = k1|e| 1+1 / α sgn(e)+k2|e| 1-1 / α sgn(e).

[0016] Furthermore, u2=∫k|s| 1+βsgn(|s|-1) sgn(s)dt.

[0017] According to another aspect of the present invention, a method for generating DC power from a DC-biased AC motor is provided, wherein the three-phase windings of the DC-biased AC motor are respectively connected to a first rectifier and a second rectifier, comprising:

[0018] (S1) Acquire DC bus voltage feedback value u dc And calculate its square. Receive bus voltage setpoint u dcref And calculate its square. Will and The input is fed into the bus voltage controller of the DC-biased AC motor provided by this invention to obtain the torque setpoint T. eref ;

[0019] (S2) Based on the torque setpoint T eref Following the maximum torque-to-current ratio control strategy, the setpoint values ​​for the d, q, and 0-axis currents are calculated. Then, the difference between the setpoint value and the feedback value of each axis current is calculated before PI control is applied to obtain the setpoint values ​​u for the d, q, and 0-axis voltages. d u q and u0;

[0020] (S3) Set the given values ​​u of the d, q, and 0 axis voltages. d u q After being combined with u0 to form a composite voltage vector, the resulting voltage vector has a phase lag of 30 degrees behind the current voltage vector and a magnitude equal to that of the composite voltage vector. The voltage vector u times s1The phase lags behind the composite voltage vector by 150 degrees, and the magnitude is equal to the composite voltage vector. The voltage vector u times s2 ;

[0021] (S4) For voltage vector u s1 Space vector pulse width modulation (SVM) is performed to obtain PWM signals PWM1-6, which are then input to the first rectifier to obtain the first voltage; the voltage vector u is then processed. s2 Space vector pulse width modulation is performed to obtain the PWM signal PWM7-12, which is then input to the second rectifier to obtain the second voltage.

[0022] (S5) Input the first voltage and the second voltage to the DC biased AC motor to generate a sinusoidal current signal with DC bias, thereby realizing the DC power generation control of the DC biased AC motor.

[0023] According to another aspect of the present invention, a DC power generation system for a DC-biased AC motor is provided, wherein the three-phase windings of the DC-biased AC motor are respectively connected to a first rectifier and a second rectifier, comprising:

[0024] The bus voltage controller, which is the bus voltage controller for a DC-biased AC motor provided by the present invention, has its first input terminal used to receive the square of the bus voltage setpoint. Its second input terminal is used to receive the square of the bus voltage feedback value. It is used to calculate the torque setpoint T eref ;

[0025] A current distributor, whose input is connected to the output of a bus voltage controller, is used to determine the torque setpoint T. eref According to the maximum torque-current ratio control strategy, calculate the given values ​​of the d, q, and 0 axis currents;

[0026] The current controller has its first input connected to the output of the current distributor, and its second input receiving feedback values ​​of the d, q, and 0-axis currents. It then calculates the difference between the setpoint and feedback value of each axis current and performs PI control to obtain the setpoint u of the d, q, and 0-axis voltages. d u q and u0;

[0027] The voltage vector generation module, whose input is connected to the output of the current controller, is used to generate the given values ​​u of the d, q, and 0-axis voltages. d u q After being combined with u0 to form a composite voltage vector, the resulting voltage vector has a phase lag of 30 degrees behind the current voltage vector and a magnitude equal to that of the composite voltage vector. The voltage vector u times s1 The phase lags behind the composite voltage vector by 150 degrees, and the magnitude is equal to the composite voltage vector. The voltage vector u times s2 ;

[0028] The first pulse width modulation module has its input terminal connected to the first output terminal of the voltage vector generation module, and its output terminal connected to the switching device of the first rectifier. It is used to control the voltage vector u. s1 Space vector pulse width modulation is performed to obtain PWM signals PWM1-6, which are then input to the first rectifier to obtain the first voltage;

[0029] The second pulse width modulation module has its input connected to the second output of the voltage vector generation module, and its output connected to the switching device of the second rectifier. It is used to control the voltage vector u. s2 Space vector pulse width modulation is performed to obtain the PWM signal PWM7-12, which is then input to the second rectifier to obtain the second voltage;

[0030] The power generation control module has a first input terminal connected to a first rectifier and a second input terminal connected to a second rectifier. It is used to collect a first current and a second current, and input the first voltage and the second voltage to the DC-biased AC motor to generate a sinusoidal current signal with DC bias, thereby realizing the DC power generation control of the DC-biased AC motor.

[0031] According to another aspect of the present invention, a DC-biased AC motor system is provided, comprising:

[0032] The first rectifier and the second rectifier, and the bus capacitors connected in parallel across the output terminals of these two rectifiers;

[0033] A DC-biased AC motor, wherein the two ends of its three-phase windings are connected to the first rectifier and the second rectifier, respectively;

[0034] And the DC power generation system of the DC biased AC motor provided by the present invention.

[0035] In summary, the above-described technical solutions conceived in this invention can achieve the following beneficial effects:

[0036] (1) The DC-biased AC motor bus voltage controller provided by this invention includes a fast-terminal sliding mode controller designed based on a fast-terminal sliding mode control law and an exponential sliding mode approach law, and an extended state controller. The fast-terminal sliding mode controller designs the sliding surface based on the error e between the square of the bus voltage setpoint and the feedback value. All other parameters are independent of the system parameters. Therefore, the parameter design process is simple, robust, and does not depend on internal system parameters. The extended state observer observes the total system disturbance in real time, further improving the system's dynamic response speed and reducing the chattering problem of the sliding mode controller, thereby improving the steady-state accuracy of the bus voltage. Furthermore, the extended state observer is less affected by the deviation of internal system parameters and has strong robustness. Overall, the DC-biased AC motor bus voltage controller provided by this invention fully considers the influence of external load changes and internal parameter deviations, is independent of system parameters, and has high control accuracy and dynamic response capability. Even under conditions of drastic changes in external load or deviations in internal system parameters, the bus voltage feedback value can always follow the setpoint.

[0037] (2) In a preferred embodiment of the DC-biased AC motor bus voltage controller provided by the present invention, the sliding surface change rate of the fast terminal sliding mode controller is... Based on this design, regardless of the value of the sliding surface s, the rate of change will be large, effectively improving the gain of the error signal and enabling the error e to converge quickly to the sliding surface. Therefore, the fast-terminal sliding mode controller designed in this invention has a fast response characteristic under all operating conditions, greatly improving the dynamic response capability of bus voltage control. Attached Figure Description

[0038] Figure 1 The phase current waveform of an existing DC-biased AC motor;

[0039] Figure 2 The main circuit structure diagram of an existing DC-biased AC motor control system;

[0040] Figure 3 A schematic diagram of the structure of a bus voltage controller for a DC-biased AC motor provided in an embodiment of the present invention;

[0041] Figure 4 This is a flowchart of a DC power generation method for a DC biased AC motor provided in an embodiment of the present invention;

[0042] Figure 5 This is a schematic diagram of the structure of a DC power generation system for a DC biased AC motor provided in an embodiment of the present invention.

[0043] Figure 6The diagram shows a comparison of bus voltage response speed and bus voltage fluctuation for different control methods provided in the embodiments of the present invention; wherein, (a) is a diagram showing the bus voltage response speed and bus voltage fluctuation when using the power generation method provided by the present invention, and (b) is a diagram showing the bus voltage response speed and bus voltage fluctuation when using a traditional control strategy. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0045] In this invention, the terms "first," "second," etc. (if present) in the invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0046] To address the problem that existing control methods for DC-biased AC motors are highly dependent on the system adoption number, resulting in poor dynamic response characteristics and reduced steady-state control accuracy of the bus voltage under conditions of drastic changes in external load or deviations in internal system parameters, this invention provides a bus voltage controller, generation method, and system for DC-biased AC motors. The overall approach involves theoretically analyzing the mathematical model of the DC-biased AC motor generation system without altering the hardware structure of the control system. This analysis fully considers the impact of changes in external load and deviations in internal parameters, leading to the design of a variable-structure sliding mode controller with low parameter dependence and high control accuracy. Furthermore, by fully considering both internal and external disturbances of the DC-biased AC motor, a corresponding extended state observer is designed. The two work together to improve system stability, control accuracy, and dynamic response capabilities.

[0047] The following is an example.

[0048] Example 1:

[0049] A bus voltage controller for a DC-biased AC motor, such as Figure 3 As shown, it includes:

[0050] The first arithmetic unit has its first input terminal used to receive the square of the bus voltage setpoint. Its second input terminal is used to receive the square of the bus voltage feedback value. It is used for calculation and The difference is used to obtain the bus voltage error e;

[0051] A fast terminal sliding mode controller, whose input is connected to the output of the first arithmetic unit, has the following expression for its sliding surface: It is used to calculate the first component u1 of the torque setpoint according to the sliding surface s and the fast terminal sliding mode control law, and to calculate the second component u2 of the torque setpoint according to the exponential sliding mode approach law;

[0052] An extended state observer, whose input is used to receive the square of the bus voltage feedback value. Its observation equation is It is used to calculate the third component z2 of the torque setpoint;

[0053] And a second arithmetic unit, whose first input is connected to the first output of the fast terminal sliding mode controller, whose second input is connected to the second output of the fast terminal sliding mode controller, and whose third input is connected to the output of the extended state observer, is used to... Calculate the torque setpoint T eref ;

[0054] Where α>1, k1>0, k2>0; sgn represents the sign function; b0=2ω r / C0, where C0 is the rated value of the bus capacitance, ω r z1 represents the mechanical angular velocity of the motor; z2 represents the square of the bus voltage feedback value. The observed value, z2 represents the sum of internal and external disturbances f of the system. all The observed values, where u represents the system input and e1 represents... The observation error, β1 and β2 are positive coefficients.

[0055] To further improve dynamic response capability, as a preferred implementation, in this embodiment, the rate of change of the sliding surface of the fast terminal sliding mode controller designed based on the exponential sliding mode reaching law is specifically as follows:

[0056]

[0057] Where k > 0, β > 0.

[0058] The sliding surface change rate designed in this embodiment based on the exponential sliding mode convergence law will have a large value regardless of the value of the sliding surface s, which effectively improves the gain of the error signal and enables the error e to converge to the sliding surface quickly.

[0059] Based on the sliding surface s and its rate of change The design can be calculated

[0060] u1=k1|e| 1+1 / α sgn(e)+k2|e| 1-1 / α sgn(e)

[0061] u2=∫k|s| 1+βsgn(s|-1) sgn(s)dt

[0062] In summary, the bus voltage controller for the DC-biased AC motor provided in this embodiment designs parameters based on the error between the square of the bus voltage setpoint and the feedback value. The parameter design process is simple, robust, and independent of internal system parameters. The sliding surface change rate, designed based on an exponential sliding mode reaching law, exhibits fast response characteristics across all operating conditions, significantly improving the system's dynamic response capability. The fast-terminal sliding mode controller further enhances the system's dynamic response speed and reduces chattering issues by observing the total system disturbance in real time through an extended state observer, thereby improving the steady-state accuracy of the bus voltage. Furthermore, the extended state observer is less affected by deviations in internal system parameters and exhibits strong robustness. Further explanation follows.

[0063] The control process of the sliding mode controller includes two stages. In the first stage, the controlled object gradually reaches the sliding surface. In the second stage, the controlled object converges from the sliding surface to zero. In this embodiment, based on the fast-termining sliding surface, when the bus voltage error e reaches the sliding surface, the bus voltage error e will converge to zero within a finite time t1, and t1 can be expressed as:

[0064]

[0065] Where e(0) is the initial value of the error. It can be seen that the smaller α is, the larger k1 and k2 are, and the smaller the time t1 for the error to converge to zero after reaching the sliding surface is.

[0066] Furthermore, according to the exponential sliding mode reaching law, the error e will reach the sliding surface in a finite time t2, and t2 can be expressed as...

[0067]

[0068] Where s(0) is the initial value of the sliding surface. It can be seen that the larger β is, the larger k is, and the smaller the time t2 for the error to reach the sliding surface is.

[0069] Based on the above analysis, it can be seen that in this embodiment, optimization can be achieved by reasonably setting parameters that are independent of system parameters, such as α, k1, k2, k, and β. It is easy to understand that the specific settings of these parameters need to consider both response speed and steady-state control effect.

[0070] The state equation of a DC generator system for a DC biased AC motor can be expressed as follows:

[0071]

[0072] in, fall For the internal disturbance f of the system in and total external disturbance f ex The sum, x1 and x2 respectively represent and f all The actual value, and Let x1 and x2 represent the derivatives respectively; b0 = 2ω r / C0, where C0 is the rated value of the bus capacitance, ω r ω is the mechanical angular velocity of the motor; u is the system input; h is the total system disturbance f. all The derivative of .

[0073] Internal disturbance f of the system in It can be represented as:

[0074]

[0075] Among them, i d i q i0 and i0 represent the currents along the d, q, and 0 axes, respectively, and T e This represents the torque feedback value; C is the actual value of the bus capacitance, ΔC = C - C0, R s Let M be the motor winding resistance and M be the motor dynamic disturbance, which can be expressed as:

[0076]

[0077] Where L0 is the DC component of the motor phase inductance and L1 is the AC component of the motor phase inductance.

[0078] External disturbances to the system f ex It can be represented as:

[0079]

[0080] Among them, R L This is the equivalent resistance of the load.

[0081] Based on the above analysis, the total system disturbance f all Directly related to system parameters such as capacitance, resistance, and inductance, the extended state observer designed in this embodiment can observe the total system disturbance in real time. In conjunction with the fast terminal sliding mode controller, it avoids dependence on system parameters while considering system disturbances.

[0082] Based on the expression of the extended state observer, z1 represents the square of the bus voltage feedback value. The observed value z1 is

[0083] z1=∫(z2+β1e1+b0T eref )dt

[0084] The sum of internal and external disturbances f of the system all The observed value z2 is

[0085] z2=∫β2e1dt

[0086] The stability of the bus voltage controller provided in this embodiment is verified and explained below.

[0087] Considering both internal and external disturbances in the system, the derivative of the error e can be expressed as:

[0088]

[0089] Furthermore, the sliding surface s can be represented as

[0090]

[0091] Where, Δf=f all -z2; x ref It is usually a constant value, so its derivative is zero.

[0092] Furthermore, by constructing the Lyapunov function V, the asymptotic stability of the system can be proven. V can be expressed as:

[0093]

[0094] Where m is a positive real number.

[0095] The derivative of V can be expressed as:

[0096]

[0097] Let m = s / Δf, then we can obtain

[0098]

[0099] In summary, the bus voltage controller for the DC-biased AC motor designed in this embodiment is progressively stable. Therefore, the bus voltage controller provided in this embodiment can be effectively applied to the bus voltage control of the DC-biased AC motor, achieving the beneficial effects of improving system stability, control accuracy, and dynamic response capability.

[0100] Example 2:

[0101] A method for generating DC power from a DC-biased AC motor, such as Figure 2 As shown, the DC-biased AC motor is connected to the first rectifier and the second rectifier respectively; the DC bus voltage u of the motor dc The motor rotor electrical angle θ can be obtained through a bus voltage sensor. e and the mechanical angular velocity ω of the motor rThe three-phase current i of the motor can be obtained through a speed sensor. abc The current is obtained from a current sensor, then input to a current coordinate transformer, and the motor d-axis current i is obtained through the following process. d q-axis current i q And zero-axis current i0:

[0102]

[0103] Among them, i a i b i c These represent the A, B, and C phase currents of the motor, respectively.

[0104] like Figure 4 As shown, the DC power generation method for a DC-biased AC motor provided in this embodiment includes:

[0105] (S1) Acquire DC bus voltage feedback value u dc And calculate its square. Receive bus voltage setpoint u dcref And calculate its square. Will and The input is given to the bus voltage controller of the DC-biased AC motor provided in Embodiment 1 above to obtain the torque setpoint T. eref ;

[0106] (S2) Based on the torque setpoint T eref Following the maximum torque-to-current ratio control strategy, the setpoint values ​​for the d, q, and 0-axis currents are calculated. Then, the difference between the setpoint value and the feedback value of each axis current is calculated before PI control is applied to obtain the setpoint values ​​u for the d, q, and 0-axis voltages. d u q and u0;

[0107] (S3) Set the given values ​​u of the d, q, and 0 axis voltages. d u q After being combined with u0 to form a composite voltage vector, the resulting voltage vector has a phase lag of 30 degrees behind the current voltage vector and a magnitude equal to that of the composite voltage vector. The voltage vector u times s1 The phase lags behind the composite voltage vector by 150 degrees, and the magnitude is equal to the composite voltage vector. The voltage vector u times s2 ;

[0108] (S4) For voltage vector u s1 Space vector pulse width modulation (SVM) is performed to obtain PWM signals PWM1-6, which are then input to the first rectifier to obtain the first voltage; the voltage vector u is then processed. s2Space vector pulse width modulation is performed to obtain the PWM signal PWM7-12, which is then input to the second rectifier to obtain the second voltage.

[0109] (S5) Input the first voltage and the second voltage to the DC biased AC motor to generate a sinusoidal current signal with DC bias, thereby realizing the DC power generation control of the DC biased AC motor.

[0110] Example 3:

[0111] A DC power generation system for a DC-biased AC motor, such as Figure 2 As shown, the DC-biased AC motor is connected to the first rectifier and the second rectifier respectively; the DC bus voltage u of the motor dc The motor rotor electrical angle θ can be obtained through a bus voltage sensor. e and the mechanical angular velocity ω of the motor r The three-phase current i of the motor can be obtained through a speed sensor. abc The current is obtained from a current sensor, then input to a current coordinate transformer, and the motor d-axis current i is obtained through the following process. d q-axis current i q And zero-axis current i0:

[0112]

[0113] Among them, i a i b i c These represent the A, B, and C phase currents of the motor, respectively.

[0114] like Figure 5 As shown, the DC power generation system for a DC-biased AC motor provided in this embodiment includes:

[0115] The bus voltage controller, which is the bus voltage controller for the DC-biased AC motor provided in Embodiment 1 above, has its first input terminal used to receive the square of the bus voltage setpoint. Its second input terminal is used to receive the square of the bus voltage feedback value. It is used to calculate the torque setpoint T eref ;

[0116] A current distributor, whose input is connected to the output of a bus voltage controller, is used to determine the torque setpoint T. eref According to the maximum torque-current ratio control strategy, calculate the given values ​​of the d, q, and 0 axis currents;

[0117] The current controller has its first input connected to the output of the current distributor, and its second input receiving feedback values ​​of the d, q, and 0-axis currents. It then calculates the difference between the setpoint and feedback value of each axis current and performs PI control to obtain the setpoint u of the d, q, and 0-axis voltages. d u q and u0; such as Figure 5 As shown, the current controller specifically includes a d-axis current controller, a q-axis current controller, and a 0-axis current controller, which are used to perform PI control on the difference between the calculated d-axis, q-axis, and 0-axis current setpoints and feedback values ​​to obtain the corresponding voltage setpoints.

[0118] The voltage vector generation module, whose input is connected to the output of the current controller, is used to generate the given values ​​u of the d, q, and 0-axis voltages. d u q After being combined with u0 to form a composite voltage vector, the resulting voltage vector has a phase lag of 30 degrees behind the current voltage vector and a magnitude equal to that of the composite voltage vector. The voltage vector u times s1 The phase lags behind the composite voltage vector by 150 degrees, and the magnitude is equal to the composite voltage vector. The voltage vector u times s2 ;like Figure 5 As shown, the voltage vector generation module specifically includes: a voltage vector synthesizer, used to synthesize the given values ​​u of the d, q, and 0 axis voltages. d u q The resultant voltage vector u is formed by combining u0 and u0. s The first voltage phase-shifting module is used to calculate the voltage vector u based on the synthesized voltage vector u. s The generated phase lags the voltage vector by 30 degrees and its magnitude is the same as the synthesized voltage vector. The voltage vector u times s1 ; and a second voltage phase-shifting module, used to calculate the synthesized voltage vector u s The generated phase lags the voltage vector by 150 degrees and its magnitude is the same as the synthesized voltage vector. The voltage vector u times s2 ;

[0119] The first pulse width modulation module has its input terminal connected to the first output terminal of the voltage vector generation module, and its output terminal connected to the switching device of the first rectifier. It is used to control the voltage vector u. s1 Space vector pulse width modulation is performed to obtain PWM signals PWM1-6, which are then input to the first rectifier to obtain the first voltage;

[0120] The second pulse width modulation module has its input connected to the second output of the voltage vector generation module, and its output connected to the switching device of the second rectifier. It is used to control the voltage vector u. s2Space vector pulse width modulation is performed to obtain the PWM signal PWM7-12, which is then input to the second rectifier to obtain the second voltage;

[0121] The power generation control module has a first input terminal connected to a first rectifier and a second input terminal connected to a second rectifier. It is used to collect a first current and a second current, and input the first voltage and the second voltage to the DC-biased AC motor to generate a sinusoidal current signal with DC bias, thereby realizing the DC power generation control of the DC-biased AC motor.

[0122] Example 4:

[0123] A DC-biased AC motor system, comprising:

[0124] The first rectifier and the second rectifier, and the bus capacitors connected in parallel across the output terminals of these two rectifiers;

[0125] A DC-biased AC motor, wherein the two ends of its three-phase windings are connected to the first rectifier and the second rectifier, respectively;

[0126] And the DC power generation system of the DC biased AC motor provided in Embodiment 3 above.

[0127] The following analysis, based on specific experimental results, further verifies the beneficial effects that this invention can achieve.

[0128] Figure 6 The diagram shows a comparison of the dynamic response and steady-state fluctuations of the bus voltage under a traditional DC power generation control strategy and the proposed DC power generation control strategy. The bus voltage command value is always maintained at 80V, and the rated speed is 1500rpm. (a) shows the bus voltage response speed and fluctuations when using the power generation method provided by this invention, and (b) shows the bus voltage response speed and fluctuations when using the traditional control strategy. Figure 6 As shown in (a) and (b), at the same rotational speed, when the load power changes abruptly from zero to 80% of the rated power, the bus voltage recovery time is 25ms and the steady-state voltage fluctuation is 0.40mV using the control strategy proposed in this invention, while the bus voltage recovery time is 67ms and the steady-state voltage fluctuation is 0.43mV using the traditional control strategy. It can be seen that the control strategy proposed in this invention can significantly improve the disturbance rejection capability of the DC biased AC motor DC generator system, reduce steady-state voltage fluctuation, and improve the response speed and steady-state accuracy of the bus voltage.

[0129] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. 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 present invention.

Claims

1. A bus voltage controller for a DC-biased AC motor, characterized in that, include: The first arithmetic unit has its first input terminal used to receive the square of the bus voltage setpoint. Its second input terminal is used to receive the square of the bus voltage feedback value. It is used for calculation and The difference is used to obtain the bus voltage error e; A fast terminal sliding mode controller, whose input is connected to the output of the first arithmetic unit, has the following expression for its sliding surface: It is used to calculate the first component u1 of the torque setpoint according to the sliding surface s and the fast terminal sliding mode control law, and to calculate the second component u2 of the torque setpoint according to the exponential sliding mode approach law; An extended state observer, whose input is used to receive the square of the bus voltage feedback value. Its observation equation is It is used to calculate the third component z2 of the torque setpoint; And a second arithmetic unit, whose first input terminal is connected to the first output terminal of the fast terminal sliding mode controller, whose second input terminal is connected to the second output terminal of the fast terminal sliding mode controller, and whose third input terminal is connected to the output terminal of the extended state observer, is used to... Calculate the torque setpoint T ere f; Where α>1, k1>0, k2>0; sgn represents the sign function; b0=2ω r / C0, where C0 is the rated value of the bus capacitance, ω r z1 represents the mechanical angular velocity of the motor; z2 represents the square of the bus voltage feedback value. The observed value, z2 represents the sum of internal and external disturbances f of the system. all The observed values, where u represents the system input and e1 represents... The observation error, β1 and β2 are positive coefficients.

2. The bus voltage controller for a DC-biased AC motor as described in claim 1, characterized in that, In the fast terminal sliding mode controller, the rate of change of the sliding surface s is: Where k>0, β>0.

3. The bus voltage controller for a DC-biased AC motor as described in claim 2, characterized in that, u1=k1|e| 1+1 / α sgn(e)+k2|e| 1-1 / α sgn(e)。 4. The bus voltage controller for a DC-biased AC motor as described in claim 3, characterized in that, u2=∫k|s| 1+βsgn(|s|-1) sgn(s)dt。 5. A method for generating DC power from a DC-biased AC motor, wherein the three-phase windings of the DC-biased AC motor are respectively connected to a first rectifier and a second rectifier, characterized in that... include: (S1) Acquire DC bus voltage feedback value u dc And calculate its square. Receive bus voltage setpoint u dcref And calculate its square. Will and The input is fed into the bus voltage controller of the DC-biased AC motor according to any one of claims 1 to 4 to obtain the torque setpoint T. eref ; (S2) Based on the torque setpoint T eref Following the maximum torque-to-current ratio control strategy, the setpoint values ​​for the d, q, and 0-axis currents are calculated. Then, the difference between the setpoint value and the feedback value of each axis current is calculated before PI control is applied to obtain the setpoint values ​​u for the d, q, and 0-axis voltages. d u q and u0; (S3) Set the given values ​​u of the d, q, and 0 axis voltages. d u q After being combined with u0 to form a composite voltage vector, the resulting voltage vector has a phase lag of 30 degrees behind the current voltage vector and a magnitude equal to that of the composite voltage vector. The voltage vector u times s1 The phase lags behind the composite voltage vector by 150 degrees, and the magnitude is equal to the composite voltage vector. The voltage vector u times s2 ; (S4) For voltage vector u s1 Space vector pulse width modulation (SVM) is performed to obtain PWM signals PWM1-6, which are then input to the first rectifier to obtain the first voltage; the voltage vector u is then processed. s2 Space vector pulse width modulation is performed to obtain the PWM signal PWM7-12, which is then input to the second rectifier to obtain the second voltage. (S5) The first voltage and the second voltage are input to the DC-biased AC motor to generate a sinusoidal current signal with DC bias, thereby realizing the DC power generation control of the DC-biased AC motor.

6. A DC power generation system for a DC-biased AC motor, wherein the three-phase windings of the DC-biased AC motor are respectively connected to a first rectifier and a second rectifier, characterized in that, include: The bus voltage controller, which is the bus voltage controller of the DC biased AC motor according to any one of claims 1 to 4, has its first input terminal used to receive the square of the bus voltage setpoint. Its second input terminal is used to receive the square of the bus voltage feedback value. It is used to calculate the torque setpoint T eref ; A current distributor, whose input is connected to the output of the bus voltage controller, is used to determine the torque setpoint T. eref According to the maximum torque-current ratio control strategy, calculate the given values ​​of the d, q, and 0 axis currents; The current controller has its first input terminal connected to the output terminal of the current distributor, and its second input terminal used to receive feedback values ​​of the d, q, and 0 axis currents. It is used to calculate the difference between the given value and the feedback value of each axis current and then perform PI control to obtain the given values ​​u of the d, q, and 0 axis voltages. d u q and u0; A voltage vector generation module, whose input is connected to the output of the current controller, is used to generate the given values ​​u of the d, q, and 0 axis voltages. d u q After being combined with u0 to form a composite voltage vector, the resulting voltage vector has a phase lag of 30 degrees behind the current voltage vector and a magnitude equal to that of the composite voltage vector. The voltage vector u times s1 The phase lags behind the composite voltage vector by 150 degrees, and the magnitude is equal to the composite voltage vector. The voltage vector u times s2 ; The first pulse width modulation module has its input terminal connected to the first output terminal of the voltage vector generation module, and its output terminal connected to the switching device of the first rectifier. It is used to control the voltage vector u. s1 Space vector pulse width modulation is performed to obtain PWM signals PWM1-6, which are then input to the first rectifier to obtain the first voltage; The second pulse width modulation module has its input connected to the second output of the voltage vector generation module, and its output connected to the switching device of the second rectifier. It is used to control the voltage vector u. s2 Space vector pulse width modulation is performed to obtain the PWM signal PWM7-12, which is then input to the second rectifier to obtain the second voltage; The power generation control module has a first input terminal connected to the first rectifier and a second input terminal connected to the second rectifier. It is used to collect a first current and a second current, and input the first voltage and the second voltage to the DC-biased AC motor to generate a sinusoidal current signal with DC bias, thereby realizing DC power generation control of the DC-biased AC motor.

7. A DC-biased AC motor system, characterized in that, include: The first rectifier and the second rectifier, and the bus capacitors connected in parallel across the output terminals of these two rectifiers; A DC-biased AC motor, wherein the two ends of its three-phase windings are connected to the first rectifier and the second rectifier, respectively; And the DC power generation system of the DC biased AC motor as described in claim 6.

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