Multi-fed brushless generator system and control method thereof

Abstract

The invention belongs to the technical field of brushless generators, and particularly discloses a multi-feed brushless generator system and a control method thereof. In the system, a control module generates a PWM pulse modulation signal, and a low-voltage machine side converter provides excitation current for a control winding according to the PWM pulse modulation signal; the multi-fed brushless generator outputs medium-voltage alternating current at the medium-voltage power winding side according to the exciting current and outputs low-voltage alternating current at the low-voltage power winding side; the medium-voltage uncontrolled rectifier converts medium-voltage alternating current output by the medium-voltage power winding side into medium-voltage direct current; the low-voltage controllable rectifier converts low-voltage alternating current output by the low-voltage power winding side into low-voltage direct current according to the PWM pulse modulation signal; the system provided by the invention can supply power to direct current systems with medium-voltage and low-voltage voltage levels at the same time, and can realize electric energy quality adjustment through cooperative control of the low-voltage controllable rectifier and the low-voltage machine-side converter.

Description

Technical Field

[0001] The present application belongs to the technical field of brushless generators, and more specifically, to a multi-fed brushless generator system and a control method thereof. Background Art

[0002] At present, the voltage level of the medium-voltage DC bus used in the integrated power system of large-tonnage and high-speed ships has reached 4~10kV, and will reach 30kV in the future, and the capacity will gradually increase from 10MW to 200MW. Among them, electronic equipment and conventional daily loads are usually powered by a low-voltage DC bus with a voltage level of 700~1000V. In order to achieve medium- and low-voltage DC hybrid power supply, the existing method is to use a topological structure that combines a medium-voltage DC power generation system with a megawatt-level large-capacity DC-DC converter in series.

[0003] The current medium- and low-voltage DC hybrid power supply system has the following main defects: (1) In terms of system topology, the generator system only outputs medium-voltage DC power and needs to rely on a large-capacity DC-DC converter connected in series to achieve medium-voltage to low-voltage DC power conversion. The power density of the entire system is low. In addition, the large-capacity DC-DC converter uses a large number of power electronic devices, which seriously reduces the system reliability. (2) In terms of control strategy, the control of the generator system and the DC-DC converter is essentially cascade control. Their control inertia is quite different, which makes it difficult to match the dynamic characteristics of the generator and converter, making it easy to cause mutual interference and system oscillation, and the system stability is insufficient. Summary of the invention

[0004] In view of the above defects or improvement needs of the prior art, the present application provides a multi-fed brushless generator system, which aims to solve the technical problems of insufficient reliability and stability of the current medium and low voltage DC hybrid power supply system.

[0005] To achieve the above-mentioned object, in a first aspect, the present application provides a multi-fed brushless generator system, comprising a topology module and a control module, wherein the control module is used to generate a first PWM pulse modulation signal and a second PWM pulse modulation signal according to feedback values ​​of a low-voltage direct current and a medium-voltage direct current; the topology module comprises: A low-voltage machine-side converter, used for providing an excitation current to a control winding side of a multi-fed brushless generator according to a first PWM pulse modulation signal; A multi-fed brushless generator, for outputting medium voltage alternating current at a medium voltage power winding side and outputting low voltage alternating current at a low voltage power winding side according to an excitation current; A medium voltage uncontrolled rectifier is used to convert the medium voltage AC power outputted from the medium voltage power winding side of the multi-fed brushless generator into medium voltage DC power; The low-voltage controlled rectifier is used to convert the low-voltage alternating current output from the low-voltage power winding side of the multi-fed brushless generator into low-voltage direct current according to the second PWM pulse modulation signal.

[0006] Preferably, the multi-fed brushless generator includes a medium-voltage power winding, a low-voltage power winding and a control winding with different pole pairs; wherein the medium-voltage power winding and the control winding are coupled through a rotor; the low-voltage power winding and the control winding are coupled through a rotor; and the medium-voltage power winding and the low-voltage power winding are coupled through a rotor.

[0007] Preferably, the topology module also includes a low-voltage DC bus capacitor, and the low-voltage DC bus capacitor, the DC side of the low-voltage controlled rectifier and the DC side of the low-voltage machine-side converter are connected in parallel, and the low-voltage DC bus capacitor is used to filter out harmonic components in the low-voltage DC power and store energy.

[0008] Preferably, the control module includes: The medium voltage DC output voltage control module is used to obtain the control winding current by subtracting the reference value of the medium voltage DC from the feedback value through PI control. Axis component reference values; A control winding frequency calculation module, used to obtain the frequency of the control winding according to the rotation speed of the multi-fed brushless generator, the rated frequency of the medium voltage power winding and the rated frequency of the low voltage power winding; A control winding frequency integrator, used for integrating the frequency of the control winding to obtain a reference angle; The control winding current conversion module is used to convert the current on the control winding side according to the reference angle. The phase current is converted into the control winding current Axis component feedback value and Axis component feedback value; Control winding current control module, used to control winding current Axis component reference value and After the axis component feedback value is subtracted, the control winding voltage is obtained through PI control. axis component reference value; it controls the winding current Axis component reference value and After the axis component feedback value is subtracted, the control winding voltage is obtained through PI control. axis component reference value; the control winding current The axis component reference value is zero; A control winding voltage conversion module is used to control the winding voltage according to the reference angle. Axis component reference values ​​and The axis component reference value is converted into the control winding voltage Axis component reference values ​​and Axis component reference values; The control winding SVPWM generator is used to control the winding voltage according to the Axis component reference values ​​and The axis component reference value generates a first PWM pulse modulation signal.

[0009] Preferably, the rotation speed of the multi-fed brushless generator satisfies: When the equivalent low voltage power rotor winding is connected in reverse phase sequence to the control rotor winding, and the equivalent medium voltage power rotor winding is connected in reverse phase sequence to the control rotor winding:

[0010] When the equivalent low voltage power rotor winding is connected in the same phase sequence as the control rotor winding, and the equivalent medium voltage power rotor winding is connected in the same phase sequence as the control rotor winding:

[0011] When the equivalent low-voltage power rotor winding is connected to the control rotor winding in reverse phase sequence, and the equivalent medium-voltage power rotor winding is connected to the control rotor winding in the same phase sequence:

[0012] When the equivalent low-voltage rotor power winding is connected in the same phase sequence as the control rotor winding, and the equivalent medium-voltage power rotor winding is connected in the opposite phase sequence to the control rotor winding:

[0013] in, is the speed of the multi-fed brushless generator, To control the winding frequency, To control the number of winding pole pairs, is the low voltage power winding frequency, is the medium voltage power winding frequency, is the number of pole pairs of low voltage power winding, is the number of pole pairs of the medium voltage power winding.

[0014] Preferably, the control module further includes: The low voltage DC output voltage control module is used to obtain the low voltage power winding current by subtracting the reference value of the low voltage DC from the feedback value through PI control. Axis component reference values; A low-voltage power winding voltage phase-locked loop, used for obtaining a voltage phase according to a three-phase voltage on the low-voltage power winding side; The low voltage power winding current conversion module is used to convert the low voltage power winding side current according to the voltage phase. Phase current is converted into low voltage power winding current Axis component feedback value and Axis component feedback value; The low voltage power winding current control module is used to control the low voltage power winding current After the reference value of the axis component is subtracted from the feedback value, the low-voltage power winding voltage is obtained through PI control. Axis component reference value; the low voltage power winding current After the axis component reference value and the feedback value are subtracted, the low voltage power winding voltage is obtained through PI control. Axis component reference value; low voltage power winding current The axis component reference value is zero; The low voltage power winding voltage conversion module is used to convert the low voltage power winding voltage according to the voltage phase. Axis component reference values ​​and The shaft component reference value is converted into the low voltage power winding voltage Axis component reference values ​​and Axis component reference values; Low voltage controlled rectifier SVPWM generator, used to adjust the voltage of low voltage power winding according to the Axis component reference values ​​and axis component reference value to generate a second PWM pulse modulation signal.

[0015] In a second aspect, the present application provides a control method for a multi-fed brushless generator system, the method comprising the following steps: Providing an excitation current to a control winding side of a multi-fed brushless generator according to a first PWM pulse modulation signal; The multi-fed brushless generator outputs medium voltage AC power on the medium voltage power winding side and outputs low voltage AC power on the low voltage power winding side according to the excitation current; Converting the medium voltage AC power outputted from the medium voltage power winding side of the multi-fed brushless generator into medium voltage DC power; Converting the low-voltage alternating current outputted from the low-voltage power winding side of the multi-fed brushless generator into low-voltage direct current according to the second PWM pulse modulation signal; A first PWM pulse modulation signal and a second PWM pulse modulation signal are generated according to the low voltage direct current and the medium voltage direct current.

[0016] Preferably, the first PWM pulse modulation signal is obtained by the following method: After subtracting the reference value of the medium voltage DC from the feedback value, the winding current is controlled by PI control. Axis component reference values; Obtaining the frequency of the control winding according to the rotation speed of the multi-fed brushless generator, the rated frequency of the medium voltage power winding and the rated frequency of the low voltage power winding; Integrate the frequency of the control winding to obtain the reference angle; According to the reference angle, the control winding side The phase current is converted into the control winding current Axis component feedback value and Axis component feedback value; The control winding current Axis component reference value and After the axis component feedback value is subtracted, the control winding voltage is obtained through PI control. Axis component reference values; The control winding current Axis component reference value and After the axis component feedback value is subtracted, the control winding voltage is obtained through PI control. axis component reference value; the control winding current The axis component reference value is zero; According to the reference angle, the winding voltage is controlled Axis component reference values ​​and The axis component reference value is converted into the control winding voltage Axis component reference values ​​and Axis component reference values; According to the control winding voltage Axis component reference values ​​and The axis component reference value generates a first PWM pulse modulation signal.

[0017] Preferably, the rotation speed of the multi-fed brushless generator satisfies: When the equivalent low voltage power rotor winding is connected in reverse phase sequence to the control rotor winding, and the equivalent medium voltage power rotor winding is connected in reverse phase sequence to the control rotor winding:

[0018] When the equivalent low voltage power rotor winding is connected in the same phase sequence as the control rotor winding, and the equivalent medium voltage power rotor winding is connected in the same phase sequence as the control rotor winding:

[0019] When the equivalent low-voltage power rotor winding is connected to the control rotor winding in reverse phase sequence, and the equivalent medium-voltage power rotor winding is connected to the control rotor winding in the same phase sequence:

[0020] When the equivalent low-voltage rotor power winding is connected in the same phase sequence as the control rotor winding, and the equivalent medium-voltage power rotor winding is connected in the opposite phase sequence to the control rotor winding:

[0021] in, is the speed of the multi-fed brushless generator, To control the winding frequency, To control the number of winding pole pairs, is the low voltage power winding frequency, is the medium voltage power winding frequency, is the number of pole pairs of low voltage power winding, is the number of pole pairs of the medium voltage power winding.

[0022] Preferably, the second PWM pulse modulation signal is obtained by the following method: After the reference value of the low voltage DC power is subtracted from the feedback value, the low voltage power winding current is obtained through PI control. Axis component reference values; Obtaining voltage phase according to the three-phase voltage on the low-voltage power winding side; According to the voltage phase, the low voltage power winding side Phase current is converted into low voltage power winding current Axis component feedback value and Axis component feedback value; The low voltage power winding current After the reference value of the axis component is subtracted from the feedback value, the low-voltage power winding voltage is obtained through PI control. Axis component reference value; the low voltage power winding current After the axis component reference value and the feedback value are subtracted, the low voltage power winding voltage is obtained through PI control. Axis component reference value; low voltage power winding current The axis component reference value is zero; According to the voltage phase, the low voltage power winding voltage Axis component reference values ​​and The shaft component reference value is converted into the low voltage power winding voltage Axis component reference values ​​and Axis component reference values; Low voltage controlled rectifier SVPWM generator, used to adjust the voltage of low voltage power winding according to the Axis component reference values ​​and axis component reference value to generate a second PWM pulse modulation signal.

[0023] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the prior art: (1) The medium- and low-voltage DC hybrid power supply system of the present application can achieve a hybrid output of medium- and low-voltage electric energy through a single multi-fed brushless generator. The controllable converters used in the system of the present application are all low-voltage converters, which greatly improves the power density and reliability of the system.

[0024] (2) The medium- and low-voltage DC hybrid power supply system of the present application abandons the traditional cascade control mode, and can synchronously adjust the medium-voltage DC bus and the low-voltage DC bus through the low-voltage machine-side converter, and can realize control without medium-voltage DC bus capacitor.

[0025] (3) In the present application, the low-voltage DC hybrid power supply system adopts a low-voltage controlled rectifier to control the low-voltage power winding, and adopts a low-voltage machine-side converter to control the control winding. Power quality regulation can be achieved through the coordinated control of the low-voltage controlled rectifier and the low-voltage machine-side converter.

[0026] (4) The present application proposes a new topology structure of a multi-fed brushless generator, in which the multi-fed brushless generator includes three sets of windings, namely a medium-voltage power winding, a low-voltage power winding and a low-voltage control winding, with different pole pairs, and all of them are coupled to each other through a rotor. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a signal flow diagram of a multi-fed brushless generator system provided in an embodiment of the present application.

[0028] Figure 2 It is a schematic diagram of the topology module structure provided in an embodiment of the present application.

[0029] Figure 3 It is a schematic diagram of the control module structure provided in an embodiment of the present application.

[0030] Figure 4 It is a schematic diagram of the structure of a multi-fed brushless generator system provided in an embodiment of the present application.

[0031] Figure 5 It is a block diagram of the medium voltage DC output voltage control principle provided in an embodiment of the present application.

[0032] Figure 6 This is a block diagram of the control winding current control principle provided in an embodiment of the present application.

[0033] Figure 7 This is a block diagram of the low voltage DC output voltage control principle provided by the embodiment of the present application. Figure 8 This is a block diagram of the low-voltage power winding current control principle provided in an embodiment of the present application. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0035] The terms "first" and "second" in the specification and claims herein are used to distinguish different objects rather than to describe a specific order of the objects. For example, a first PWM pulse modulation signal and a second PWM pulse modulation signal are used to distinguish different PWM pulse modulation signals rather than to describe a specific order of the PWM pulse modulation signals.

[0036] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0037] The present application provides an embodiment of a brushless multi-fed generator system, such as Figure 1 As shown, it includes a topology module and a control module; the control module receives the three-phase current of the control winding, the three-phase current of the low-voltage power winding, the three-phase voltage of the low-voltage power winding, the motor speed, the reference value of the medium-voltage DC bus voltage, the feedback value of the medium-voltage DC bus voltage, the reference value of the low-voltage DC bus voltage, and the feedback value of the low-voltage DC bus voltage output by the topology module, and after PI control and coordinate transformation, uses an SVPWM generator to output two PWM pulse modulation signals; the topology module controls the brushless multi-fed generator according to the two PWM pulse modulation signals provided by the control module, thereby realizing power supply to the system of medium voltage and low voltage levels at the same time; like Figure 2 As shown, the topology module includes: a multi-fed brushless generator, a low-voltage DC bus capacitor, a medium-voltage uncontrolled rectifier, a low-voltage controlled rectifier, and a low-voltage machine-side converter; The multi-fed brushless generator includes three sets of windings, namely, a medium voltage power winding, a low voltage power winding and a low voltage control winding with different pole pairs; the medium voltage power winding and the control winding are coupled through a rotor; the low voltage power winding and the control winding are coupled through a rotor; the medium voltage power winding and the low voltage power winding are coupled through a rotor; The AC side of the medium voltage uncontrolled rectifier is connected to the medium voltage power winding of the multi-fed brushless generator; the AC side of the low voltage controllable rectifier is connected to the low voltage power winding of the multi-fed brushless generator; the AC side of the low voltage machine side converter is connected to the low voltage control winding of the multi-fed brushless generator; the DC side of the low voltage controllable rectifier and the DC side of the low voltage machine side converter are connected in parallel with the low voltage DC bus capacitor; The medium voltage uncontrolled rectifier is used to convert the AC voltage output on the medium voltage power winding side into a DC voltage; the low voltage machine side converter is used to provide excitation current for the low voltage control winding according to the PWM pulse modulation signal of the low voltage machine side converter; the low voltage controlled rectifier is used to adjust the low voltage power winding current and control the low voltage DC voltage according to the PWM pulse modulation signal of the low voltage controlled rectifier; the low voltage DC bus capacitor is used to filter out the harmonic components in the low voltage DC voltage and store energy.

[0038] like Figure 3 As shown, The control module consists of two parts. The first part includes: Medium voltage DC output voltage control module, control winding current control module, control winding voltage conversion module, control winding current conversion module, control winding frequency integrator, low voltage machine side converter SVPWM generator, control winding frequency calculation module.

[0039] The connection relationship is: A medium voltage DC output voltage control module, a control winding current control module, a control winding voltage conversion module and a low voltage machine side converter SVPWM generator are connected in sequence; The first input end of the control winding current conversion module is connected to the control winding, the second input end thereof is connected to the first output end of the control winding frequency integrator, and the output end thereof is connected to the input end of the control winding current control module; The second output terminal of the control winding frequency integrator is connected to the input terminal of the control winding voltage conversion module.

[0040] The functions of each part are: The medium voltage DC output voltage control module is based on the reference value of the medium voltage DC bus voltage. The medium voltage DC bus voltage feedback value after low pass filter , through PI control, the medium voltage DC bus voltage is adjusted to obtain the control winding current Axis component reference value .

[0041] The control winding current control module controls the winding current according to Axis component reference value and control winding current Axis component feedback value , through PI control to control the winding current The axis component is adjusted to obtain the control winding voltage Axis component reference value .

[0042] And according to the control winding current Axis component reference value and control winding current Axis component feedback value , through PI control to control the winding current The axis component is adjusted to obtain the control winding voltage Axis component reference value .

[0043] The control winding voltage conversion module is used to convert the rotating Control winding voltage in coordinate system Axis component reference value and control winding voltage Axis component reference value Transformed into two-phase stationary Control winding voltage in coordinate system Axis component reference value and Axis component reference value .

[0044] The control winding frequency integrator is used to integrate the control winding frequency to obtain the reference angle of the control winding voltage conversion module and the control winding current conversion module. .

[0045] The control winding current conversion module is used to collect the current from the control winding side of the brushless multi-fed generator. Phase current and Phase current Transformed to Coordinate system for controlling winding current Axis component feedback value and current Axis component feedback value .

[0046] The SVPWM generator of the low-voltage machine-side converter uses the ideal stator flux circle of a three-phase symmetrical motor when powered by a three-phase symmetrical sinusoidal voltage as a reference standard, and makes appropriate switches with different switching modes of the three-phase inverter to form a PWM pulse signal for the low-voltage machine-side converter.

[0047] The control winding frequency calculation module and the low voltage power winding frequency calculation module calculate the motor speed according to the motor speed. Rated frequency of medium voltage power winding , obtain the control winding frequency under different phase sequence connection methods The calculation method is: When the equivalent low-voltage power rotor winding is connected to the control rotor winding in reverse phase sequence, and the equivalent medium-voltage power rotor winding is connected to the control rotor winding in reverse phase sequence, the relationship between the rotor speed, the medium-voltage power winding frequency, the control winding frequency and the low-voltage power winding frequency is: ; When the equivalent low-voltage power rotor winding is connected in phase sequence with the control rotor winding, and the equivalent medium-voltage power rotor winding is connected in phase sequence with the control rotor winding, the relationship between the rotor speed, the medium-voltage power winding frequency, the control winding frequency and the low-voltage power winding frequency is: ; When the equivalent low-voltage power rotor winding is connected to the control rotor winding in reverse phase sequence, and the equivalent medium-voltage power rotor winding is connected to the control rotor winding in the same phase sequence, the relationship between the rotor speed, the medium-voltage power winding frequency, the control winding frequency and the low-voltage power winding frequency is: ; When the equivalent low-voltage power rotor winding is connected to the control rotor winding in the same phase sequence, and the equivalent medium-voltage power rotor winding is connected to the control rotor winding in the opposite phase sequence, the relationship between the rotor speed, the medium-voltage power winding frequency, the control winding frequency and the low-voltage power winding frequency is: ; in, is the low voltage power winding frequency; is the medium voltage power winding frequency; To control the winding frequency; Rotor speed; is the number of pole pairs of low voltage power winding; is the number of pole pairs of medium voltage power winding; To control the number of winding pole pairs.

[0048] The second part contains: Low-voltage DC output voltage control module, low-voltage power winding current control module, low-voltage power winding voltage conversion module, low-voltage power winding current conversion module, low-voltage machine-side converter SVPWM generator, control winding voltage phase-locked loop.

[0049] The connection relationship is: A low voltage DC output voltage control module, a low voltage power winding current control module, a low voltage power winding voltage conversion module and a low voltage controlled rectifier SVPWM generator are connected in sequence; The first input end of the low-voltage power winding current conversion module is connected to the low-voltage power winding, the second input end thereof is connected to the first output end of the low-voltage power winding voltage phase-locked loop, and the output end thereof is connected to the input end of the low-voltage power winding current control module; The second output end of the low-voltage power winding voltage phase-locked loop is connected to the input end of the low-voltage power winding voltage conversion module.

[0050] The functions of each part are: The low voltage DC output voltage control module is based on the reference value of the low voltage DC bus voltage. The low voltage DC bus voltage feedback value after low pass filter , through PI control, the low-voltage DC bus voltage is adjusted to obtain the low-voltage power winding current Axis component reference value .

[0051] The low voltage power winding current control module controls the current of the low voltage power winding according to the Axis component reference value and low voltage power winding current Axis component feedback value , through PI control of the low voltage power winding current The axis component is adjusted to obtain the low voltage power winding voltage Axis component reference value .

[0052] And according to the low voltage power winding current Axis component reference value and low voltage power winding current Axis component feedback value , through PI control of the low voltage power winding current The axis component is adjusted to obtain the low voltage power winding voltage Axis component reference value .

[0053] The low voltage power winding voltage conversion module is used to convert the rotating Low voltage power winding voltage in coordinate system Axis component reference value and low voltage power winding voltage Axis component reference value Transformed into two-phase stationary The voltage of low voltage power winding in the coordinate system Axis component reference value and Axis component reference value .

[0054] The low-voltage power winding voltage phase-locked loop is used to calculate the low-voltage power winding voltage phase, and the low-voltage power winding voltage phase serves as a reference angle for the low-voltage power winding voltage conversion module and the low-voltage power winding current conversion module.

[0055] The low voltage power winding current conversion module is used to collect the current from the low voltage power winding side of the brushless multi-fed generator. Phase current and Phase current Transformed to Coordinate system of low voltage power winding current Axis component feedback value and current Axis component feedback value .

[0056] The low-voltage controlled rectifier SVPWM generator uses the ideal stator flux circle of a three-phase symmetrical motor when powered by a three-phase symmetrical sinusoidal voltage as a reference standard, and makes appropriate switching with different switching modes of the three-phase inverter to form a low-voltage controlled rectifier PWM pulse signal.

[0057] Example 1 Embodiment 1 is a brushless multi-fed generator system, such as Figure 4 As shown, it includes a topology module and a control module; The topology module includes: multi-fed brushless generator, low-voltage DC bus capacitor, medium-voltage uncontrolled rectifier, low-voltage controlled rectifier, and low-voltage machine-side converter; The multi-fed brushless generator includes three sets of windings, namely, a medium voltage power winding, a low voltage power winding and a low voltage control winding with different pole pairs; The medium voltage power winding is coupled with the control winding through the rotor; the low voltage power winding is coupled with the control winding through the rotor; the medium voltage power winding is coupled with the low voltage power winding through the rotor; The AC side of the medium voltage uncontrolled rectifier is connected to the medium voltage power winding of the multi-fed brushless generator; the AC side of the low voltage controllable rectifier is connected to the low voltage power winding of the multi-fed brushless generator; the AC side of the low voltage machine side converter is connected to the low voltage control winding of the multi-fed brushless generator; the DC side of the low voltage controllable rectifier and the DC side of the low voltage machine side converter are connected in parallel with the low voltage DC bus capacitor; The medium voltage uncontrolled rectifier is used to convert the AC voltage output from the medium voltage power winding side into a DC voltage; The low-voltage machine-side converter is used to provide an excitation current for the low-voltage control winding according to a PWM pulse modulation signal of the low-voltage machine-side converter; The low voltage controlled rectifier is used to adjust the low voltage power winding current and control the low voltage DC voltage according to the low voltage controlled rectifier PWM pulse modulation signal; Low-voltage DC bus capacitors are used to filter out harmonic components in low-voltage DC voltage and store energy.

[0058] In practical applications, the low-voltage DC power filtered by the low-voltage DC bus capacitor is connected to the low-voltage DC bus to supply power to the low-voltage DC load or to operate in parallel with the low-voltage DC grid; the medium-voltage DC power is connected to the medium-voltage DC bus to supply power to the medium-voltage DC load or to operate in parallel with the medium-voltage DC grid; Therefore, the topology module can achieve mixed output of medium and low voltage electric energy through a single generator, and the controllable converters used in the control system are all low voltage converters, which greatly improves the system power density and reliability.

[0059] The control module includes: a medium voltage DC output voltage control module, a control winding current control module, a control winding voltage conversion module, a control winding current conversion module, a control winding frequency integrator, a low voltage machine side converter SVPWM generator, a control winding frequency calculation module, a low voltage DC output voltage control module, a low voltage power winding current control module, a low voltage power winding voltage conversion module, a low voltage power winding current conversion module, a low voltage machine side converter SVPWM generator, and a control winding voltage phase locked loop; The medium voltage DC output voltage control module is based on the reference value of the medium voltage DC bus voltage. The medium voltage DC bus voltage feedback value after low pass filter , through PI control, the low voltage DC bus voltage is adjusted to obtain the control winding current Axis component reference value .

[0060] Specifically, Figure 5 As shown, the medium voltage DC output voltage control module includes a low-pass filter, a first adder and a first PI regulator; Feedback value of low-pass filter to medium voltage DC bus voltage Filter to obtain noise-free medium voltage DC bus voltage feedback value ; The first adder calculates The reference value of the medium voltage DC bus voltage and input the difference to a first PI regulator; The first PI regulator performs PI control on the difference and outputs a control winding current. Axis component reference value .

[0061] Among them, the control winding current Axis component reference value is 0.

[0062] Among them, the specific calculation formula of the low-pass filter is:

[0063] in, It is the current noise-free medium-voltage DC bus voltage feedback value of the multi-fed brushless generator; For the The feedback value of the current noisy medium-voltage DC bus voltage of the multi-fed brushless generator obtained by calculation; is the cut-off frequency of the first low-pass filter; is the sampling period, which is determined by the hardware used by the user; For the The feedback value of the current noisy medium-voltage DC bus voltage of the multi-fed brushless generator calculated in this way is Input to the first PI regulator.

[0064] The control winding current control module controls the winding current according to Axis component reference value and control winding current Axis component feedback value , through PI control to control the winding current The axis component is adjusted to obtain the control winding voltage Axis component reference value On the other hand, according to the control winding current Axis component reference value and control winding current Axis component feedback value , through PI control to control the winding current The axis component is adjusted to obtain the control winding voltage Axis component reference value .

[0065] Specifically, Figure 6 As shown, the control winding current control module includes a second adder, a third adder, a second PI regulator and a third PI regulator; The second adder is used to control the winding current Axis component reference value The control winding current Axis component feedback value make a mistake; The second PI regulator is used to Perform PI control to obtain the control winding voltage Axis component reference value ; The third adder is used to control the winding current Axis component reference value The control winding current Axis component feedback value The difference between the control winding current and Axis component reference value is equal to 0; The third PI controller is used to Perform PI control to obtain the control winding voltage Axis component reference value .

[0066] The control winding voltage conversion module is used to convert the rotating Control winding voltage in coordinate system Axis component reference value and control winding voltage Axis component reference value Transformed into two-phase stationary Control winding voltage in coordinate system Axis component reference value and Axis component reference value .

[0067] The specific method is: The integrator is used to control the winding frequency The reference angle of the control winding voltage conversion module and the control winding current conversion module is obtained by integration. ;Specifically:

[0068] in, The current given value of the control winding voltage phase; T is the sampling period, which is determined by the hardware used by the user; the number of operations j =1, …, n ; Indicates j The current given value of the control winding voltage and frequency calculated by the calculation; the result of the calculation Sent to the control winding voltage conversion module.

[0069] use The control winding voltage Axis component reference value and control winding voltage Axis component reference value From the rotation The coordinate system is transformed into two-phase stationary Coordinate system, get the control winding voltage Axis component reference value and Axis component reference value , the transformation expression is:

[0070] According to the control winding voltage Axis component reference value and Axis component reference value , using SVPWM algorithm to generate modulation signal, so that the low voltage machine side converter outputs corresponding excitation current to the control winding; The control winding current conversion module is used to collect the current from the control winding side of the brushless multi-fed generator. Phase current and Phase current Transformed to Coordinate system for controlling winding current Axis component feedback value and current Axis component feedback value .

[0071] The specific method is: According to the collected multi-fed brushless generator control winding Phase current and Phase current , calculate the control winding Phase current , the calculation method is as follows:

[0072] Using the control winding current reference , transform the three-phase current of the control winding into Coordinate system for controlling winding current Axis component feedback value and current Axis component feedback value , the specific transformation method is:

[0073] The control winding frequency calculation module is based on the motor speed Rated frequency of medium voltage power winding , obtain the control winding frequency under different phase sequence connection methods The calculation method is: When the equivalent medium voltage power rotor winding and the control rotor winding are connected in reverse phase sequence, the relationship between the rotor speed, the rated frequency of the power winding and the control winding frequency is: ; When the equivalent medium voltage power rotor winding is connected in the same phase sequence as the control rotor winding, the relationship between the rotor speed, the rated frequency of the power winding and the control winding frequency is: ; in, is the number of pole pairs of medium voltage power winding; To control the number of winding pole pairs.

[0074] The low voltage DC output voltage control module is based on the reference value of the low voltage DC bus voltage. The low voltage DC bus voltage feedback value after low pass filter , through PI control, the low-voltage DC bus voltage is adjusted to obtain the low-voltage power winding current Axis component reference value ; Specifically, Figure 7 As shown, the low voltage DC output voltage control module includes a low pass filter, a fourth adder and a fourth PI regulator; Feedback value of low-pass filter to low-voltage DC bus voltage Filter to obtain noise-free low-voltage DC bus voltage feedback value ; The fourth adder calculates The reference value of the low voltage DC bus voltage and input the difference to a fourth PI regulator; The fourth PI regulator performs PI control on the difference and outputs the current of the low-voltage power winding. Axis component reference value .

[0075] Among them, the low voltage power winding current Axis component reference value is 0; Among them, the specific calculation formula of the low-pass filter is:

[0076] in, It is the current noise-free low-voltage DC bus voltage feedback value of the multi-fed brushless generator; For the The feedback value of the current noisy low-voltage DC bus voltage of the multi-fed brushless generator obtained by calculation; is the cut-off frequency of the first low-pass filter; is the sampling period, which is determined by the hardware used by the user; For the The feedback value of the current noisy low-voltage DC bus voltage of the multi-fed brushless generator calculated in this way is Input to the fourth PI regulator.

[0077] The low voltage power winding current control module controls the current of the low voltage power winding according to the Axis component reference value and low voltage power winding current Axis component feedback value , through PI control of the low voltage power winding current The axis component is adjusted to obtain the low voltage power winding voltage Axis component reference value On the other hand, according to the low voltage power winding current Axis component reference value and low voltage power winding current Axis component feedback value , through PI control of the low voltage power winding current The axis component is adjusted to obtain the low voltage power winding voltage Axis component reference value .

[0078] Specifically, Figure 8 As shown, the low-voltage power winding current control module includes a fifth adder, a sixth adder, a fifth PI regulator and a sixth PI regulator; The fifth adder is used to convert the low voltage power winding current Axis component reference value and low voltage power winding current Axis component feedback value make a mistake; The fifth PI regulator is used to Perform PI control to obtain low voltage power winding voltage Axis component reference value ; The sixth adder is used to convert the low voltage power winding current Axis component reference value and low voltage power winding current Axis component feedback value The difference is made; among which, the low voltage power winding current Axis component reference value is equal to 0; The sixth PI controller is used to Perform PI control to obtain low voltage power winding voltage Axis component reference value .

[0079] The low voltage power winding voltage conversion module is used to convert the rotating Low voltage power winding voltage in coordinate system Axis component reference value and low voltage power winding voltage Axis component reference value Transformed into two-phase stationary The voltage of low voltage power winding in the coordinate system Axis component reference value and Axis component reference value .

[0080] use The low voltage power winding voltage Axis component reference value and low voltage power winding voltage Axis component reference value From the rotation The coordinate system is transformed into two-phase stationary Coordinate system, get the low voltage power winding voltage Axis component reference value and Axis component reference value , the transformation expression is:

[0081] According to the control of low voltage power group voltage Axis component reference value and Axis component reference value , using SVPWM algorithm to generate modulation signal, so that the low-voltage controlled rectifier outputs corresponding excitation current to the low-voltage power winding; The low voltage power winding current conversion module is used to collect the current from the low voltage power winding side of the brushless multi-fed generator. Phase current and Phase current Transformed to Coordinate system of low voltage power winding current Axis component feedback value and current Axis component feedback value .

[0082] The specific method is: According to the collected data of low voltage power winding of multi-fed brushless generator Phase current and Phase current , calculate the low voltage power winding Phase current , the calculation method is as follows:

[0083] Using the low voltage power winding current reference , transform the three-phase current of the low-voltage power winding into Coordinate system of low voltage power winding current Axis component feedback value and current Axis component feedback value , the specific transformation method is:

[0084] Example 2 Embodiment 2 is a control method for a multi-fed brushless generator system, the control method comprising: Providing an excitation current to a control winding of a multi-fed brushless generator according to a first PWM pulse modulation signal; The multi-fed brushless generator outputs medium voltage AC power on the medium voltage power winding side according to the excitation current, and outputs low voltage AC power on the low voltage power winding side; Converting the medium voltage AC power outputted from the medium voltage power winding side into medium voltage DC power; Converting the low-voltage alternating current outputted from the low-voltage power winding side into low-voltage direct current according to the second PWM pulse modulation signal; A first PWM pulse modulation signal and a second PWM pulse modulation signal are generated according to the low voltage direct current and the medium voltage direct current.

[0085] It should be understood that the above method embodiment is used to control the system in the above embodiment 1, and the corresponding steps in the method, their implementation principles and technical effects are similar to those described in the above embodiment 1. The specific steps of the method can refer to the corresponding processes in the above embodiment 1, and will not be repeated here.

[0086] It should be understood that the various numerical numbers involved in the embodiments of the present application are only used for the convenience of description and are not used to limit the scope of the embodiments of the present application.

[0087] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A multi-fed brushless generator system, characterized in that: It includes a topology module and a control module, wherein the control module is used to generate a first PWM pulse modulation signal and a second PWM pulse modulation signal according to feedback values ​​of low-voltage direct current and medium-voltage direct current; the topology module includes: A low-voltage machine-side converter, used for providing an excitation current to a control winding side of a multi-fed brushless generator according to a first PWM pulse modulation signal; A multi-fed brushless generator, for outputting medium voltage alternating current at a medium voltage power winding side and outputting low voltage alternating current at a low voltage power winding side according to an excitation current; A medium voltage uncontrolled rectifier is used to convert the medium voltage AC power outputted from the medium voltage power winding side of the multi-fed brushless generator into medium voltage DC power; The low-voltage controlled rectifier is used to convert the low-voltage alternating current output from the low-voltage power winding side of the multi-fed brushless generator into low-voltage direct current according to the second PWM pulse modulation signal.

2. The multi-fed brushless generator system according to claim 1, characterized in that: The multi-fed brushless generator comprises a medium voltage power winding, a low voltage power winding and a control winding with different pole pairs; wherein the medium voltage power winding is coupled with the control winding through a rotor; the low voltage power winding is coupled with the control winding through a rotor; and the medium voltage power winding is coupled with the low voltage power winding through a rotor.

3. The multi-fed brushless generator system according to claim 1, characterized in that: The topology module also includes a low-voltage DC bus capacitor, which is connected in parallel with the DC side of the low-voltage controlled rectifier and the DC side of the low-voltage machine-side converter. The low-voltage DC bus capacitor is used to filter out harmonic components in the low-voltage DC power and store energy.

4. The multi-fed brushless generator system according to claim 1, characterized in that: The control module comprises: The medium voltage DC output voltage control module is used to obtain the control winding current by subtracting the reference value of the medium voltage DC from the feedback value through PI control. Axis component reference values; A control winding frequency calculation module, used to obtain the frequency of the control winding according to the rotation speed of the multi-fed brushless generator, the rated frequency of the medium voltage power winding and the rated frequency of the low voltage power winding; A control winding frequency integrator, used for integrating the frequency of the control winding to obtain a reference angle; The control winding current conversion module is used to convert the current on the control winding side according to the reference angle. The phase current is converted into the control winding current Axis component feedback value and Axis component feedback value; Control winding current control module, used to control winding current Axis component reference value and After the axis component feedback value is subtracted, the control winding voltage is obtained through PI control. Axis component reference value; controls the winding current Axis component reference value and After the axis component feedback value is subtracted, the control winding voltage is obtained through PI control. axis component reference value; the control winding current The axis component reference value is zero; A control winding voltage conversion module is used to control the winding voltage according to the reference angle. Axis component reference values ​​and The axis component reference value is converted into the control winding voltage Axis component reference values ​​and Axis component reference values; The control winding SVPWM generator is used to control the winding voltage according to the Axis component reference values ​​and The axis component reference value generates a first PWM pulse modulation signal.

5. The multi-fed brushless generator system according to claim 1, 2 or 4, characterized in that: The speed of the multi-fed brushless generator satisfies: When the equivalent low voltage power rotor winding is connected in reverse phase sequence to the control rotor winding, and the equivalent medium voltage power rotor winding is connected in reverse phase sequence to the control rotor winding: When the equivalent low voltage power rotor winding is connected in the same phase sequence as the control rotor winding, and the equivalent medium voltage power rotor winding is connected in the same phase sequence as the control rotor winding: When the equivalent low-voltage power rotor winding is connected to the control rotor winding in reverse phase sequence, and the equivalent medium-voltage power rotor winding is connected to the control rotor winding in the same phase sequence: When the equivalent low-voltage rotor power winding is connected in the same phase sequence as the control rotor winding, and the equivalent medium-voltage power rotor winding is connected in the opposite phase sequence to the control rotor winding: in, is the speed of the multi-fed brushless generator, To control the winding frequency, To control the number of winding pole pairs, is the low voltage power winding frequency, is the medium voltage power winding frequency, is the number of pole pairs of low voltage power winding, is the number of pole pairs of the medium voltage power winding.

6. The multi-fed brushless generator system according to claim 1, characterized in that: The control module also includes: The low voltage DC output voltage control module is used to obtain the low voltage power winding current by subtracting the reference value of the low voltage DC from the feedback value through PI control. Axis component reference values; A low-voltage power winding voltage phase-locked loop, used for obtaining a voltage phase according to a three-phase voltage on the low-voltage power winding side; The low voltage power winding current conversion module is used to convert the low voltage power winding side current according to the voltage phase. Phase current is converted into low voltage power winding current Axis component feedback value and Axis component feedback value; The low voltage power winding current control module is used to control the low voltage power winding current After the reference value of the axis component is subtracted from the feedback value, the low-voltage power winding voltage is obtained through PI control. Axis component reference value; the low voltage power winding current After the axis component reference value and the feedback value are subtracted, the low voltage power winding voltage is obtained through PI control. Axis component reference value; low voltage power winding current The axis component reference value is zero; The low voltage power winding voltage conversion module is used to convert the low voltage power winding voltage according to the voltage phase. Axis component reference values ​​and The shaft component reference value is converted into the low voltage power winding voltage Axis component reference values ​​and Axis component reference values; Low voltage controlled rectifier SVPWM generator, used to adjust the voltage of low voltage power winding according to the Axis component reference values ​​and axis component reference value to generate a second PWM pulse modulation signal.

7. A control method based on the multi-fed brushless generator system according to claim 1, characterized in that: The control method comprises: Providing an excitation current to a control winding side of a multi-fed brushless generator according to a first PWM pulse modulation signal; The multi-fed brushless generator outputs medium voltage AC power on the medium voltage power winding side and outputs low voltage AC power on the low voltage power winding side according to the excitation current; Converting the medium voltage AC power outputted from the medium voltage power winding side of the multi-fed brushless generator into medium voltage DC power; Converting the low-voltage alternating current outputted from the low-voltage power winding side of the multi-fed brushless generator into low-voltage direct current according to the second PWM pulse modulation signal; A first PWM pulse modulation signal and a second PWM pulse modulation signal are generated according to the low voltage direct current and the medium voltage direct current.

8. The control method according to claim 7, characterized in that: The first PWM pulse modulation signal is specifically obtained by the following method: After subtracting the reference value of the medium voltage DC from the feedback value, the winding current is controlled by PI control. Axis component reference values; Obtaining the frequency of the control winding according to the rotation speed of the multi-fed brushless generator, the rated frequency of the medium voltage power winding and the rated frequency of the low voltage power winding; Integrate the frequency of the control winding to obtain the reference angle; According to the reference angle, the control winding side The phase current is converted into the control winding current Axis component feedback value and Axis component feedback value; The control winding current Axis component reference value and After the axis component feedback value is subtracted, the control winding voltage is obtained through PI control. Axis component reference values; The control winding current Axis component reference value and After the axis component feedback value is subtracted, the control winding voltage is obtained through PI control. axis component reference value; the control winding current The axis component reference value is zero; According to the reference angle, the winding voltage is controlled Axis component reference values ​​and The axis component reference value is converted into the control winding voltage Axis component reference values ​​and Axis component reference values; According to the control winding voltage Axis component reference values ​​and The axis component reference value generates a first PWM pulse modulation signal.

9. The control method according to claim 7 or 8, characterized in that: The speed of the multi-fed brushless generator satisfies: When the equivalent low voltage power rotor winding is connected in reverse phase sequence to the control rotor winding, and the equivalent medium voltage power rotor winding is connected in reverse phase sequence to the control rotor winding: When the equivalent low voltage power rotor winding is connected in the same phase sequence as the control rotor winding, and the equivalent medium voltage power rotor winding is connected in the same phase sequence as the control rotor winding: When the equivalent low-voltage power rotor winding is connected to the control rotor winding in reverse phase sequence, and the equivalent medium-voltage power rotor winding is connected to the control rotor winding in the same phase sequence: When the equivalent low-voltage rotor power winding is connected in the same phase sequence as the control rotor winding, and the equivalent medium-voltage power rotor winding is connected in the opposite phase sequence to the control rotor winding: in, is the speed of the multi-fed brushless generator, To control the winding frequency, To control the number of winding pole pairs, is the low voltage power winding frequency, is the medium voltage power winding frequency, is the number of pole pairs of low voltage power winding, is the number of pole pairs of the medium voltage power winding.

10. The control method according to claim 7, characterized in that: The second PWM pulse modulation signal is specifically obtained by the following method: After the reference value of the low voltage DC power is subtracted from the feedback value, the low voltage power winding current is obtained through PI control. Axis component reference values; Obtaining voltage phase according to the three-phase voltage on the low-voltage power winding side; According to the voltage phase, the low voltage power winding side Phase current is converted into low voltage power winding current Axis component feedback value and Axis component feedback value; The low voltage power winding current After the reference value of the axis component is subtracted from the feedback value, the low-voltage power winding voltage is obtained through PI control. Axis component reference value; the low voltage power winding current After the axis component reference value and the feedback value are subtracted, the low voltage power winding voltage is obtained through PI control. Axis component reference value; low voltage power winding current The axis component reference value is zero; According to the voltage phase, the low voltage power winding voltage Axis component reference values ​​and The shaft component reference value is converted into the low voltage power winding voltage Axis component reference values ​​and Axis component reference values; Low voltage controlled rectifier SVPWM generator, used to adjust the voltage of low voltage power winding according to the Axis component reference values ​​and axis component reference value to generate a second PWM pulse modulation signal.

Images