阅读说明：本技术 基于谐波发电机的磁阻尼控制方法 (Magnetic damping control method based on harmonic generator ) 是由 张志华 张艳清 周皓楠 蔡华 马逊 闫少强 李秋君 李鲁阳 于 2020-05-21 设计创作，主要内容包括：本发明涉及磁阻尼控制技术领域,公开了一种基于谐波发电机的磁阻尼控制方法。该方法包括：利用三相四桥臂变流器将谐波发电机的交流电整流成直流电；利用储能单元通过电容存储直流电；利用电流采样器对谐波发电机的各相集电线圈的电流进行采集；根据采集的各相集电线圈的电流计算各相零序电流值；根据各相零序电流值和各相零序电流指令值通过PI控制得到各相零序电压指令值；根据各相零序电压指令值和谐波发电机的各相发电控制电压指令值得到PWM变流器调制波；对调制波进行PWM调制生成PWM波；通过PWM波控制电力电子开关器件的开断将储能单元中存储的电能转化成各相零序电流阻尼控制值,将各相零序电流阻尼控制值注入至各相集电线圈,以实现磁阻尼控制。(The invention relates to the technical field of magnetic damping control and discloses a magnetic damping control method based on a harmonic generator. The method comprises the following steps: rectifying alternating current of the harmonic generator into direct current by using a three-phase four-bridge arm converter; storing direct current through a capacitor by using an energy storage unit; collecting the current of each phase current collecting coil of the harmonic generator by using a current sampler; calculating the zero sequence current value of each phase according to the acquired current of each phase current collecting coil; obtaining each phase zero sequence voltage instruction value through PI control according to each phase zero sequence current value and each phase zero sequence current instruction value; obtaining a PWM converter modulation wave according to each phase zero sequence voltage instruction value and each phase power generation control voltage instruction value of the harmonic generator; carrying out PWM modulation on the modulation wave to generate a PWM wave; the on-off of the power electronic switching device is controlled through the PWM wave to convert the electric energy stored in the energy storage unit into each phase zero sequence current damping control value, and each phase zero sequence current damping control value is injected into each phase current collecting coil to realize magnetic damping control.)

1. A magnetic damping control method based on a harmonic generator is characterized by comprising the following steps:

rectifying alternating current of a harmonic generator into direct current by using a three-phase four-leg converter, wherein a U-phase bridge arm, a V-phase bridge arm and a W-phase bridge arm of the three-phase four-leg converter are respectively connected with a U-phase current collector coil, a V-phase current collector coil and a W-phase current collector coil of the harmonic generator, an N-phase bridge arm of the three-phase four-leg converter is connected with a neutral point of the harmonic generator, and the U-phase bridge arm, the V-phase bridge arm, the W-phase bridge arm and the N-phase bridge arm of the converter all comprise power electronic devices and diodes which are reversely connected with the power electronic devices in parallel;

storing the direct current by using an energy storage unit through a capacitor, wherein the capacitor and the energy storage unit are connected in parallel at the output side of the three-phase four-leg converter;

collecting the current of each phase current collecting coil of the harmonic generator by using a current sampler, wherein the current sampler is arranged between the harmonic generator and the three-phase four-leg converter;

calculating the zero sequence current value of each phase according to the acquired current of each phase current collecting coil;

obtaining each phase zero sequence voltage instruction value through PI control according to each phase zero sequence current value and each phase zero sequence current instruction value;

obtaining a PWM converter modulation wave according to each phase zero sequence voltage instruction value and each phase power generation control voltage instruction value of the harmonic generator;

performing PWM modulation on the modulation wave to generate a PWM wave;

and the PWM wave controls the on-off of the power electronic switching device to convert the electric energy stored in the energy storage unit into each phase zero sequence current damping control value, and each phase zero sequence current damping control value is injected into each phase current collecting coil, so that the magnetic damping control is realized.

2. The method of claim 1, wherein calculating the phase zero-sequence current values from the collected current for the phase current collector coils comprises:

establishing a virtual three-phase balance current of a U phase by taking the current of the U-phase current collecting coil as a reference, establishing a virtual three-phase balance current of a V phase by taking the current of the V-phase current collecting coil as a reference, and establishing a virtual three-phase balance current of a W phase by taking the current of the W-phase current collecting coil as a reference;

and calculating a U-phase zero-sequence current value according to the virtual three-phase balance current of the U-phase, calculating a V-phase zero-sequence current value according to the virtual three-phase balance current of the V-phase, and calculating a W-phase zero-sequence current value according to the virtual three-phase balance current of the W-phase.

3. The method of claim 2,

calculating a U-phase zero-sequence current value from the virtual three-phase balance current of the U-phase by:

wherein, I_u0Is a U-phase zero-sequence current value, I_uaIs a virtual a-phase balance current of U phase_ubIs a virtual b-phase balance current of the U-phase, I_ucA virtual c-phase balance current for the U-phase;

calculating a V-phase zero-sequence current value from the virtual three-phase balance current of the V-phase by:

wherein, I_v0Is a V-phase zero-sequence current value, I_vaIs a virtual a-phase balance current of V-phase, I_vbIs a virtual b-phase balance current of the V-phase, I_vcA virtual c-phase balance current for the V-phase;

calculating the W-phase zero-sequence current value according to the virtual three-phase balance current of the W-phase by the following formula:

wherein, I_w0Is a W-phase zero-sequence current value, I_waIs a virtual a-phase balance current of W phase, I_wbIs a virtual b-phase balance current of W phase, I_wcThe current is balanced for the virtual c-phase of the W-phase.

4. The method of claim 3, wherein obtaining each phase zero-sequence voltage command value by PI control based on each phase zero-sequence current value and each phase zero-sequence current command value comprises:

subtracting the zero-sequence current value of each phase and the zero-sequence current instruction value of each phase according to the phase to obtain corresponding difference values;

and obtaining the zero sequence voltage instruction value of each phase by controlling each corresponding difference value through PI.

5. The method according to claim 4, wherein obtaining the PWM converter modulation wave based on the respective phase zero-sequence voltage command values and the respective phase generation control voltage command values of the harmonic generator comprises:

and adding the zero-sequence voltage instruction value of each phase and the power generation control voltage instruction value of each phase of the harmonic generator respectively according to the phase to obtain the modulation wave of the PWM converter.

6. The method of claim 5, wherein PWM modulating the modulated wave to generate a PWM wave comprises:

and comparing the modulation wave with a carrier wave to generate a PWM wave.

7. The method of claim 6, wherein the carrier wave is a triangular wave.

Technical Field

The invention relates to the technical field of magnetic damping control, in particular to a magnetic damping control method based on a harmonic generator.

Background

The superconductive electric suspension type magnetic suspension train generates strong magnetic field through the vehicle-mounted superconductor and generates propelling, suspending and guiding forces through the interaction with the ground coil. The superconducting suspension technology has the advantages that: 1. the suspension height is large, generally more than 100 mm; 2. the suspension does not need global control; 3. the power is cut off from the outside, and the vehicle cannot suddenly lose the suspension force as long as the speed exists; 4. a vehicle-mounted excitation power supply is not needed; 5. the superconducting coil is hollow and light in weight. Due to the advantages of the superconducting suspension technology, the technology is suitable for being used in high-speed magnetic suspension.

Since the suspension characteristic of the suspension technology is a negative damping characteristic, in order to reduce the vibration of the train during running, a damping coil needs to be installed, and a control algorithm controls an inverter to inject a control current into the damping coil, so that the damping coil generates an attractive force and a repulsive force, and further generates a damping force to reduce the vibration of the train during running.

The Japanese sorb test line adopts a power generation PWM converter to inject zero-sequence current into a collecting coil to realize a magnetic damping function, so that the negative damping characteristic of superconducting electric suspension is improved, and the power generation and magnetic damping functions are simultaneously realized by a power generation coil of a harmonic generator and the PWM converter. The zero sequence current is the current amount which is obtained by averaging the sum of three-phase balance currents and is not related to three phases in three phases. In the strategy for controlling magnetic damping (as shown in fig. 1), the japanese sorb test line adopts the zero-sequence current value (the current independent of the power of each phase and obtained by averaging the currents of each phase) obtained by substituting the sampled currents of the three-phase collecting coils into the following formula.

Then passing through a zero sequence current I₀And a zero sequence current instruction value obtained by vehicle body state operationAnd comparing and outputting a voltage signal of zero sequence control through PI control, and adding the voltage signal of each phase output by the harmonic generation controller to obtain an output voltage modulation wave of the PWM converter.

The existing control strategy can meet the magnetic damping control requirement when the three phases are balanced, but when the collecting coil generates back electromotive force and the three phases are unbalanced, the three-phase current can be in the same phase with the back electromotive force of the three-phase collecting coil due to the control effect of the harmonic power generation controller, so that the high internal power factor output energy of the collecting coil is ensured, the three-phase current of the collecting coil at the moment is the three-phase unbalanced current, the actual zero-sequence current value of each phase cannot be obtained through the formula (1), and the magnetic damping control when the three phases are unbalanced cannot be performed.

Disclosure of Invention

The invention provides a magnetic damping control method based on a harmonic generator, which can solve the problems in the prior art.

The invention provides a magnetic damping control method based on a harmonic generator, wherein the method comprises the following steps:

rectifying alternating current of a harmonic generator into direct current by using a three-phase four-leg converter, wherein a U-phase bridge arm, a V-phase bridge arm and a W-phase bridge arm of the three-phase four-leg converter are respectively connected with a U-phase current collector coil, a V-phase current collector coil and a W-phase current collector coil of the harmonic generator, an N-phase bridge arm of the three-phase four-leg converter is connected with a neutral point of the harmonic generator, and the U-phase bridge arm, the V-phase bridge arm, the W-phase bridge arm and the N-phase bridge arm of the converter all comprise power electronic devices and diodes which are reversely connected with the power electronic devices in parallel;

storing the direct current by using an energy storage unit through a capacitor, wherein the capacitor and the energy storage unit are connected in parallel at the output side of the three-phase four-leg converter;

collecting the current of each phase current collecting coil of the harmonic generator by using a current sampler, wherein the current sampler is arranged between the harmonic generator and the three-phase four-leg converter;

calculating the zero sequence current value of each phase according to the acquired current of each phase current collecting coil;

obtaining each phase zero sequence voltage instruction value through PI control according to each phase zero sequence current value and each phase zero sequence current instruction value;

obtaining a PWM converter modulation wave according to each phase zero sequence voltage instruction value and each phase power generation control voltage instruction value of the harmonic generator;

performing PWM modulation on the modulation wave to generate a PWM wave;

and the PWM wave controls the on-off of the power electronic switching device to convert the electric energy stored in the energy storage unit into each phase zero sequence current damping control value, and each phase zero sequence current damping control value is injected into each phase current collecting coil, so that the magnetic damping control is realized.

Preferably, calculating the zero-sequence current values of the phases according to the collected current of the current collecting coils of the phases comprises:

establishing a virtual three-phase balance current of a U phase by taking the current of the U-phase current collecting coil as a reference, establishing a virtual three-phase balance current of a V phase by taking the current of the V-phase current collecting coil as a reference, and establishing a virtual three-phase balance current of a W phase by taking the current of the W-phase current collecting coil as a reference;

and calculating a U-phase zero-sequence current value according to the virtual three-phase balance current of the U-phase, calculating a V-phase zero-sequence current value according to the virtual three-phase balance current of the V-phase, and calculating a W-phase zero-sequence current value according to the virtual three-phase balance current of the W-phase.

Preferably, the U-phase zero-sequence current value is calculated from the virtual three-phase balance current of the U-phase by:

wherein, I_u0Is a U-phase zero-sequence current value, I_uaIs a virtual a-phase balance current of U phase_ubIs a virtual b-phase balance current of the U-phase, I_ucA virtual c-phase balance current for the U-phase;

calculating a V-phase zero-sequence current value from the virtual three-phase balance current of the V-phase by:

wherein, I_v0Is a V-phase zero-sequence current value, I_vaIs a virtual a-phase balance current of V-phase, I_vbIs a virtual b-phase balance current of the V-phase, I_vcA virtual c-phase balance current for the V-phase;

calculating the W-phase zero-sequence current value according to the virtual three-phase balance current of the W-phase by the following formula:

wherein, I_w0Is a W-phase zero-sequence current value, I_waIs a virtual a-phase balance current of W phase, I_wbIs a virtual b-phase balance current of W phase, I_wcThe current is balanced for the virtual c-phase of the W-phase.

Preferably, obtaining the zero-sequence voltage command value of each phase through PI control according to the zero-sequence current value of each phase and the zero-sequence current command value of each phase includes:

subtracting the zero-sequence current value of each phase and the zero-sequence current instruction value of each phase according to the phase to obtain corresponding difference values;

and obtaining the zero sequence voltage instruction value of each phase by controlling each corresponding difference value through PI.

Preferably, obtaining the PWM converter modulation wave according to the zero-sequence voltage command value of each phase and the power generation control voltage command value of each phase of the harmonic generator includes:

and adding the zero-sequence voltage instruction value of each phase and the power generation control voltage instruction value of each phase of the harmonic generator respectively according to the phase to obtain the modulation wave of the PWM converter.

Preferably, PWM modulating the modulated wave to generate a PWM wave includes:

and comparing the modulation wave with a carrier wave to generate a PWM wave.

Preferably, the carrier wave is a triangular wave.

By the technical scheme, magnetic damping control and non-contact power supply can be realized by utilizing the harmonic generator and the converter at the same time, and a damping coil is not required to be additionally added, namely a matched damping controller is obtained; and, for the back emf that the harmonic generator produced, under three-phase balance and three-phase unbalance, the invention can realize the effective magnetic damping control.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.

FIG. 1 shows a schematic diagram of a magnetic damping control strategy in the prior art;

FIG. 2 illustrates a flow diagram of a harmonic generator based magnetic damping control method according to an embodiment of the present invention;

FIG. 3 shows a schematic diagram of a harmonic generator converter based on a harmonic generator according to an embodiment of the invention;

FIG. 4 shows a schematic diagram of a magnetic damping control strategy according to one embodiment of the invention.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

The relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate. In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

Fig. 2 shows a flow chart of a harmonic generator based magnetic damping control method according to an embodiment of the invention.

The method can be applied, for example, to magnetic damping control of a magnetic levitation train.

Fig. 3 shows a schematic diagram of a harmonic generator converter based on a harmonic generator according to an embodiment of the invention.

As shown in fig. 2, an embodiment of the present invention provides a magnetic damping control method based on a harmonic generator, wherein the method includes:

s100, rectifying the alternating current of the harmonic generator into direct current by using a three-phase four-leg converter,

as shown in fig. 3, a U-phase bridge arm 3, a V-phase bridge arm 4 and a W-phase bridge arm 5 of the three-phase four-bridge arm converter (PWM converter) are respectively connected to a U-phase current collector coil, a V-phase current collector coil and a W-phase current collector coil of a harmonic generator 1, an N-phase bridge arm 6 of the three-phase four-bridge arm converter is connected to a neutral point of the harmonic generator, and the U-phase bridge arm, the V-phase bridge arm, the W-phase bridge arm and the N-phase bridge arm of the converter each include a power electronic device 2 and a diode connected in reverse parallel to the power electronic device 2;

the neutral line 10 is formed by a connecting line between the N-phase bridge arm 6 of the converter of the three-phase four-bridge arm converter and the neutral point of the harmonic generator. Each phase leg may comprise two power electronic devices 2 and two diodes, one diode being connected in anti-parallel with each power electronic device 2.

For example, a harmonic generator-based harmonic generation converter comprising a three-phase four-leg converter and a harmonic generator can be used for realizing non-contact power supply of a magnetic levitation train.

S102, storing the direct current by using an energy storage unit through a capacitor, where the capacitor 7 and the energy storage unit 8 are connected in parallel to an output side (direct current side) of the three-phase four-leg converter, as shown in fig. 3;

that is, the ac side of the three-phase four-leg converter is three-phase ac power independent of each other, and the dc side has 1 dc power supply (energy storage unit) in total.

S104, collecting the current of each phase current collecting coil of the harmonic generator by using a current sampler, where the current sampler 11 is disposed between the harmonic generator 1 and the three-phase four-leg converter, as shown in fig. 3;

for example, a current sampler 11 may be disposed between the U-phase bridge arm 3 and the U-phase current collector to collect a current of the U-phase current collector, a current sampler 11 may be disposed between the V-phase bridge arm 4 and the V-phase current collector to collect a current of the V-phase current collector, and a current sampler 11 may be disposed between the W-phase bridge arm 5 and the W-phase current collector to collect a current of the W-phase current collector.

S106, calculating the zero sequence current value of each phase according to the collected current of each phase current collecting coil;

s108, obtaining each phase zero sequence voltage instruction value through PI control according to each phase zero sequence current value and each phase zero sequence current instruction value;

the zero-sequence current command value for each phase may be calculated in advance from a measurement value of a vehicle body vibration sensor (for example, a speed sensor, an acceleration sensor, or a position sensor), for example.

S110, obtaining a PWM converter modulation wave according to each phase zero sequence voltage instruction value and each phase power generation control voltage instruction value of the harmonic generator;

the generation control voltage command value of each phase of the harmonic generator can be obtained by the existing generation control strategy (generation control algorithm), which is not limited in the present invention.

S112, carrying out PWM modulation on the modulation wave to generate a PWM wave;

and S114, converting the electric energy stored in the energy storage unit into each phase zero sequence current damping control value through the on-off of the PWM wave control power electronic switching device, and injecting each phase zero sequence current damping control value into each phase current collecting coil, thereby realizing magnetic damping control.

By the technical scheme, magnetic damping control and non-contact power supply (for example, non-contact power supply for vehicle-mounted electric equipment of a magnetic suspension train) can be realized simultaneously by using the harmonic generator and the converter, and a matched damping controller can be realized without additionally increasing a damping coil; and, for the back emf that the harmonic generator produced, under three-phase balance and three-phase unbalance, the invention can realize the effective magnetic damping control.

That is, the invention is not only suitable for the three-phase balanced power supply on the alternating current side, but also suitable for the control of the three-phase unbalanced power supply. In addition, a three-phase four-leg converter can be adopted to rectify the electric energy generated by the harmonic generator, and the converter rectifies alternating current generated by the harmonic generator, the frequency and the amplitude of which change along with the change of the vehicle speed, into direct current to supply power to a vehicle-mounted electric load (connected with the energy storage unit in parallel) 9.

With continued reference to fig. 3, the circuit shown in fig. 3 may include a U-phase bridge arm, a V-phase bridge arm, a W-phase bridge arm, and an N-phase bridge arm, respectively sample three-phase currents, respectively control three phases independently, and simultaneously control the N-phase bridge arm, so that the sum of three-phase unbalanced current and three-phase zero-sequence current may flow through the N-phase path, thereby implementing zero-sequence current control under three-phase imbalance.

As shown in fig. 3, the current collecting coils of each phase of the harmonic generator 1 may be connected in a star connection manner.

The power electronic device 2 is an insulated gate transistor IGBT or a metal oxide semiconductor field effect transistor MOSFET. For example, the MOSFET may be a SiC-MOSFET (silicon carbide MOSFET). The energy storage unit 9 may be a battery pack.

It will be appreciated by persons skilled in the art that the above description of the power electronics device 2 is merely exemplary and not intended to limit the present invention.

According to an embodiment of the present invention, calculating the zero-sequence current values of the phases according to the collected current of the current collecting coils of the phases includes:

establishing a virtual three-phase balance current of a U phase by taking the current of the U-phase current collecting coil as a reference, establishing a virtual three-phase balance current of a V phase by taking the current of the V-phase current collecting coil as a reference, and establishing a virtual three-phase balance current of a W phase by taking the current of the W-phase current collecting coil as a reference;

and calculating a U-phase zero-sequence current value according to the virtual three-phase balance current of the U-phase, calculating a V-phase zero-sequence current value according to the virtual three-phase balance current of the V-phase, and calculating a W-phase zero-sequence current value according to the virtual three-phase balance current of the W-phase.

In accordance with one embodiment of the present invention,

calculating a U-phase zero-sequence current value from the virtual three-phase balance current of the U-phase by:

wherein, I_u0Is a U-phase zero-sequence current value, I_uaIs a virtual a-phase balance current of U phase_ubIs a virtual b-phase balance current of the U-phase, I_ucA virtual c-phase balance current for the U-phase;

calculating a V-phase zero-sequence current value from the virtual three-phase balance current of the V-phase by:

wherein, I_v0Is a V-phase zero-sequence current value, I_vaIs a virtual a-phase balance current of V-phase, I_vbIs a virtual b-phase balance current of the V-phase, I_vcA virtual c-phase balance current for the V-phase;

calculating the W-phase zero-sequence current value according to the virtual three-phase balance current of the W-phase by the following formula:

wherein, I_w0Is a W-phase zero-sequence current value, I_waIs a virtual a-phase balance current of W phase, I_wbIs a virtual b-phase balance current of W phase, I_wcThe current is balanced for the virtual c-phase of the W-phase.

According to an embodiment of the present invention, obtaining the zero-sequence voltage command value of each phase by PI control according to the zero-sequence current value of each phase and the zero-sequence current command value of each phase includes:

subtracting the zero-sequence current value of each phase and the zero-sequence current instruction value of each phase according to the phase to obtain corresponding difference values;

and obtaining the zero sequence voltage instruction value of each phase by controlling each corresponding difference value through PI.

According to an embodiment of the present invention, obtaining a PWM converter modulation wave according to each phase zero-sequence voltage command value and each phase generation control voltage command value of a harmonic generator includes:

and adding the zero-sequence voltage instruction value of each phase and the power generation control voltage instruction value of each phase of the harmonic generator respectively according to the phase to obtain the modulation wave of the PWM converter.

According to an embodiment of the present invention, PWM modulating the modulated wave to generate a PWM wave includes:

and comparing the modulation wave with a carrier wave to generate a PWM wave.

Wherein the carrier wave may be a triangular wave.

FIG. 4 shows a schematic diagram of a magnetic damping control strategy according to one embodiment of the invention.

As shown in fig. 4, by sampling three-phase unbalanced current (I)_u，I_v，I_w) The three-phase balance currents (U-phase: i is_ua，I_ub，I_uc(ii) a Phase V: i is_va，I_vb，I_vc(ii) a Phase W: i is_wa，I_wb，I_wc(ii) a ) Then, the zero sequence current value (I) of each phase of the three phases is calculated in real time through formulas (2), (3) and (4)_u0；I_v0；I_w0) And respectively with the zero sequence current command value (I)_{0_ref}) Calculating difference, and respectively generating three-phase zero-sequence voltage command values through a PI controllerThen the generated zero sequence voltage instruction value and each phase power generation control voltage instruction value generated by the harmonic generator power generation control algorithmThe PWM modulated waves are obtained by addition.

The generation of the generation control voltage command value for each phase of the harmonic generator may be performed, for example, as follows: the current collected by the current sampler 11 can be used as a control quantity to participate in control, based on the control quantity and a corresponding control strategy, the output voltage required when the high power factor and the output power requirement are met can be obtained, the output voltage can be used as a modulation wave to be compared with a carrier wave (triangular wave) to obtain a PWM wave, and the PWM wave controls the conduction and the disconnection of a power electronic device, so that the output voltage of the alternating current side of the three-phase four-leg converter is controlled, and therefore the U phase, the V phase and the W phase of the three-phase four-leg converter are respectively equivalent to a controllable three-phase alternating current power supply. That is, the high power factor of the ac side and the requirement of the output power of the dc side can be achieved by the corresponding control algorithm.

It should be understood by those skilled in the art that although the above embodiments of the present invention describe only the case of three phases, they are only exemplary and not intended to limit the present invention. For example, for four or more phases, either three-phase balanced or three-phase unbalanced, would be equally applicable.

It can be seen from the above embodiments that the harmonic generator controls the PWM converter according to the power generation control algorithm to complete the power generation function of the harmonic generator, and rectifies the ac power generated by each current collecting coil of the harmonic generator into dc power to charge the dc power supply, and the power flows from the ac side to the dc power supply. Thereby, contactless power supply to the electric equipment can be realized. The zero sequence current control algorithm controls the PWM converter to complete a magnetic damping function, electric energy of a direct current power supply is converted into zero sequence current which is respectively injected into each current collecting coil of the harmonic generator, damping force is generated on the current collecting coils through the injected zero sequence current so as to achieve damping control, and power flows from the direct current power supply to the harmonic generator. Therefore, under the condition of three-phase unbalance of the harmonic generator, the zero-sequence current of each phase can be obtained, and the zero-sequence current is injected to realize the magnetic damping function.

That is, the harmonic generator can be controlled by the same group of PWM converters to generate magnetic force to realize magnetic damping function while the electric energy generated by the harmonic generator supplies power to each electric device on the vehicle.

In the description of the present invention, it is to be understood that the orientation or positional relationship indicated by the orientation words such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal" and "top, bottom", etc. are usually based on the orientation or positional relationship shown in the drawings, and are only for convenience of description and simplicity of description, and in the case of not making a reverse description, these orientation words do not indicate and imply that the device or element being referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore, should not be considered as limiting the scope of the present invention; the terms "inner and outer" refer to the inner and outer relative to the profile of the respective component itself.

Spatially relative terms, such as "above … …," "above … …," "above … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

It should be noted that the terms "first", "second", and the like are used to define the components, and are only used for convenience of distinguishing the corresponding components, and the terms have no special meanings unless otherwise stated, and therefore, the scope of the present invention should not be construed as being limited.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.