Multi-frequency harmonic generation device and method with voltage and current output ports

Abstract

The invention discloses a multi-frequency harmonic generation device and method with a voltage and current output port, and relates to the field of power electronic converter application, and the key points of the technical scheme are as follows: a voltage source, a transformer, an inductor, an AC / DC converter, a DC capacitor, a first switch and a voltage source type H bridge group are sequentially connected along the multi-frequency voltage output direction; a multi-frequency voltage output part is formed; a voltage source, a transformer, an inductor, an alternating current-direct current converter, a direct current capacitor, a second switch, a DCV-DCI converter and a current source type H bridge group are sequentially connected along the multi-frequency current output direction to form a multi-frequency current output part; wherein the AC-DC converter is controlled by a first control system, the voltage source type H bridge group is controlled by a second control system, the DCV-DCI converter is controlled by a third control system, and the current source type H bridge group is controlled by a fourth control system.

Description

Technical Field

[0001] The present invention relates to the application field of power electronic converters, and more particularly to a multi-frequency harmonic generation device and method with voltage and current output ports. Background Art

[0002] Wind and solar power generation, as well as high-speed trains, all rely on power electronic converters for grid connection, resulting in a large-scale "power electronic" power system. While power electronic converters offer excellent power conversion performance, they also introduce a series of oscillation and instability issues across the entire frequency range due to their complex control systems, nonlinear variations, strong coupling characteristics, and broadband characteristic harmonics.

[0003] Currently, oscillation and instability problems are caused by the mismatch of impedance characteristics between power electronic converters and power networks. Harmonic generation devices are the key to impedance measurement. Therefore, how to generate multi-frequency harmonics with controllable amplitude and frequency and two outputs of voltage and current is an urgent problem that needs to be solved. Summary of the Invention

[0004] The purpose of the present invention is to provide a multi-frequency harmonic generation device and method with voltage and current output ports, which can be used for wide-band impedance measurement of power systems, traction power supply systems, and new energy power generation systems, as well as resonance point identification of power networks such as power grids and traction networks.

[0005] The above technical objectives of the present invention are achieved through the following technical solutions: A first aspect of the present invention provides a multi-frequency harmonics generating device having a voltage and current output port, the device comprising: Along the direction of multi-frequency voltage output, a voltage source, a transformer, an inductor, an AC / DC converter, a DC capacitor, a first switch and a voltage source type H-bridge group are sequentially connected to form a multi-frequency voltage output part; Along the direction of multi-frequency current output, a voltage source, a transformer, an inductor, an AC-DC converter, a DC capacitor, a second switch, a DCV-DCI converter and a current source type H-bridge group are connected in sequence to form a multi-frequency current output part; The AC / DC converter is controlled by a first control system, the voltage source H-bridge group is controlled by a second control system, the DCV-DCI converter is controlled by a third control system, and the current source H-bridge group is controlled by a fourth control system. The first control system adopts constant DC voltage control, the second control system adopts target multi-frequency voltage carrier phase-shift modulation, the third control system adopts constant DC current control, and the fourth control system adopts target multi-frequency current carrier phase-shift modulation.

[0006] In one implementation, the primary side of the transformer is connected to a voltage source, the secondary side of the transformer is connected to an inductor and then to the input side of an AC / DC converter, and the output side of the AC / DC converter is connected to a DC capacitor; The DC capacitor is connected in parallel with a first port and a second port. The first port is connected to the first switch and then to the input side of the voltage source H-bridge group. The output side of the voltage source H-bridge group is a multi-frequency voltage output port. The second port is connected to the second switch and then to the input side of the DCV-DCI converter. The output side of the DCV-DCI converter is connected to the input side of the current source H-bridge group. The output side of the current source H-bridge group is a multi-frequency current output port.

[0007] In one implementation, the first switch and the second switch are used to switch the multi-frequency voltage output part and the multi-frequency current output part.

[0008] In one implementation, the voltage source H-bridge group is composed of n voltage source H-bridges, the input side of which is n voltage source H-bridges connected in parallel, and the output side of which is n voltage source H-bridges connected in series; wherein n is a positive integer.

[0009] In one implementation, the current source H-bridge group is composed of n current source H-bridges, the input side of which is n current source H-bridges connected in parallel, and the output side of which is n current source H-bridges connected in series; wherein n is a positive integer.

[0010] In one implementation, the transformer is a step-down transformer.

[0011] In one implementation, the voltage source is an AC voltage source.

[0012] A second aspect of the present invention provides a method for generating multi-frequency harmonics using a multi-frequency harmonics generating device having a voltage and current output port as provided in the first aspect of the present invention, the method comprising: Outputting a first control signal through a first control system causes the AC / DC converter to convert an AC voltage into a DC voltage, closing the first switch, and outputting a second control signal through a second control system causes the voltage source H-bridge group to output a controlled multi-frequency voltage; wherein the amplitude of the multi-frequency voltage output portion is controllable by adjusting the voltage of the first control signal output by the first control system, and the frequency of the multi-frequency voltage output portion is controllable by adjusting the frequency component of the second control signal output by the second control system, thereby obtaining a multi-frequency voltage with controllable amplitude and frequency; A first control signal is output through the first control system, causing the AC-DC converter to convert the AC voltage into a DC voltage and close the second switch. A third control signal is output through the third control system, causing the DCV-DCI converter to convert the DC voltage into a DC current. A fourth control signal is output through the fourth control system, causing the current source H-bridge group to output a controlled multi-frequency current. The amplitude of the multi-frequency current output portion is controllable by adjusting the current magnitude of the third control signal output by the third control system, and the frequency component of the fourth control signal output by the fourth control system is adjusted to achieve controllable frequency of the multi-frequency current output, thereby obtaining a multi-frequency current with controllable amplitude and frequency.

[0013] In one implementation, the second control system outputs the second control signal expressed as: ,in, 、 、…、 The frequency composition of the multi-frequency voltage, 、 、…、 is the phase of each frequency component of the multi-frequency voltage.

[0014] In one implementation, the fourth control system outputs a fourth control signal expressed as: ;in, 、 、…、 is the frequency component of the multi-frequency current, 、 、…、 is the phase of each frequency component of the multi-frequency current.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The device can generate multi-frequency harmonics with controllable amplitude and frequency, and has two output interfaces: voltage and current, which makes it applicable to a wider range of objects and scenarios.

[0016] 2. The hardware topology of the device is easy to implement, and the switching process of the device output interface is simple. The corresponding output interface can be selected through simple switch operation.

[0017] 3. The control method of the device is simple and effective. By adjusting the DC voltage / current reference value set in the control system, the amplitude of the output harmonics can be controlled. By adjusting the frequency composition of the multi-frequency voltage / current reference signal, the frequency of the output harmonics can be controlled. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings: Figure 1 A schematic diagram of a multi-frequency harmonics generating device with voltage and current output ports provided by an embodiment of the present invention; Figure 2 A schematic diagram of a multi-frequency voltage output by a multi-frequency harmonic generating device provided in an embodiment of the present invention; Figure 3 A schematic diagram of multi-frequency current output by a multi-frequency harmonic generating device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0019] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with examples and drawings. The exemplary embodiments of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0020] It should be noted that the terms "include" or "may include" used in various embodiments of the present application indicate the presence of the claimed function, operation or element, and do not limit the addition of one or more functions, operations or elements. In addition, as used in various embodiments of the present application, the terms "include", "have" and their cognates are only intended to indicate specific features, numbers, steps, operations, elements, components or combinations of the foregoing items, and should not be understood as first excluding the presence of one or more other features, numbers, steps, operations, elements, components or combinations of the foregoing items or the possibility of adding one or more features, numbers, steps, operations, elements, components or combinations of the foregoing items.

[0021] It should be understood that terms such as "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0022] Please refer to Figure 1 , Figure 1 A schematic diagram of a multi-frequency harmonics generating device with voltage and current output ports provided by an embodiment of the present invention, such as Figure 1 As shown, the device includes: Along the direction of multi-frequency voltage output, a voltage source, a transformer, an inductor, an AC / DC converter, a DC capacitor, a first switch and a voltage source type H-bridge group are sequentially connected to form a multi-frequency voltage output part; Along the direction of multi-frequency current output, a voltage source, a transformer, an inductor, an AC-DC converter, a DC capacitor, a second switch, a DCV-DCI converter and a current source type H-bridge group are connected in sequence to form a multi-frequency current output part; Among them, the AC-DC converter is controlled by the first control system, the voltage source H-bridge group is controlled by the second control system, the DCV-DCI converter is controlled by the third control system, and the current source H-bridge group is controlled by the fourth control system; among them, the first control system adopts constant DC voltage control, the second control system adopts target multi-frequency voltage carrier phase-shift modulation, the third control system adopts constant DC current control, and the fourth control system adopts target multi-frequency current carrier phase-shift modulation.

[0023] like Figure 1 As shown in the figure, the AC-DC converter is an AC-DC converter that can convert AC voltage into DC voltage.

[0024] Specifically, the primary side of the transformer is connected to a voltage source, the secondary side of the transformer is connected to an inductor and then to the input side of the AC / DC converter, and the output side of the AC / DC converter is connected to a DC capacitor; The DC capacitor is connected in parallel with a first port and a second port. The first port is connected to the first switch and then to the input side of the voltage source H-bridge group. The output side of the voltage source H-bridge group is a multi-frequency voltage output port. The second port is connected to the second switch and then to the input side of the DCV-DCI converter. The output side of the DCV-DCI converter is connected to the input side of the current source H-bridge group. The output side of the current source H-bridge group is a multi-frequency current output port.

[0025] Specifically, the first switch and the second switch are used to switch the multi-frequency voltage output part and the multi-frequency current output part.

[0026] For example, when the first switch is disconnected and the second switch is closed, the multi-frequency current output part can be controlled to output multi-frequency current; when the first switch is closed and the second switch is disconnected, the multi-frequency voltage output part can be controlled to output multi-frequency voltage; when both the first switch and the second switch are closed, the multi-frequency current output part and the multi-frequency voltage output part can be controlled to operate simultaneously.

[0027] Specifically, the voltage source type H-bridge group is composed of n voltage source type H-bridges, the input side of which is n voltage source type H-bridges connected in parallel, and the output side of which is n voltage source type H-bridges connected in series; wherein n is a positive integer.

[0028] Specifically, the current source type H-bridge group is composed of n current source type H-bridges, the input side of which is n current source type H-bridges connected in parallel, and the output side of which is n current source type H-bridges connected in series; wherein n is a positive integer.

[0029] Specifically, the transformer is a step-down transformer.

[0030] Specifically, the voltage source is an AC voltage source.

[0031] An embodiment of the present invention further provides a method for generating multi-frequency harmonics using the multi-frequency harmonics generating device having voltage and current output ports described in the above embodiment, the method comprising: Outputting a first control signal through a first control system causes the AC / DC converter to convert an AC voltage into a DC voltage, closing the first switch, and outputting a second control signal through a second control system causes the voltage source H-bridge group to output a controlled multi-frequency voltage; wherein the amplitude of the multi-frequency voltage output portion is controllable by adjusting the voltage of the first control signal output by the first control system, and the frequency of the multi-frequency voltage output portion is controllable by adjusting the frequency component of the second control signal output by the second control system, thereby obtaining a multi-frequency voltage with controllable amplitude and frequency; A first control signal is output through the first control system, causing the AC-DC converter to convert the AC voltage into a DC voltage and close the second switch. A third control signal is output through the third control system, causing the DCV-DCI converter to convert the DC voltage into a DC current. A fourth control signal is output through the fourth control system, causing the current source H-bridge group to output a controlled multi-frequency current. The amplitude of the multi-frequency current output portion is controllable by adjusting the current magnitude of the third control signal output by the third control system, and the frequency component of the fourth control signal output by the fourth control system is adjusted to achieve controllable frequency of the multi-frequency current output, thereby obtaining a multi-frequency current with controllable amplitude and frequency.

[0032] Specifically, the expression of the second control signal output by the second control system is: ,in, 、 、…、 The frequency composition of the multi-frequency voltage, 、 、…、 is the phase of each frequency component of the multi-frequency voltage.

[0033] For frequency 、 、…、 The operator can control the frequency according to the required frequency. For the phase of each frequency component, the peak value of the multi-frequency voltage can be reduced by setting the phase deviation.

[0034] Specifically, the expression of the fourth control signal output by the fourth control system is: ;in, 、 、…、 is the frequency component of the multi-frequency current, 、 、…、 is the phase of each frequency component of the multi-frequency current.

[0035] For frequency 、 、…、 The operator can control the frequency according to the required frequency. For the phase of each frequency component, the peak value of the multi-frequency current can be reduced by setting the phase deviation.

[0036] Use Figure 1 The device shown generates a multi-frequency voltage with a time domain amplitude of 10V, a frequency range of 200-300Hz, and a frequency interval of 20Hz. The specific method is: A. Multi-frequency voltage reference signal synthesis: The multi-frequency voltage reference signal is synthesized by the second control system, and its expression is: ,in: 、 、…、 The frequency composition of the multi-frequency voltage can be controlled by the operator according to the required frequency. In this embodiment, it is set to 200Hz, 220Hz, 240Hz, 260Hz, 280Hz, and 300Hz. 、 、…、 The phase of each frequency component of the multi-frequency voltage is set to 0, π / 6, 4π / 6, 9π / 6, 16π / 6, and 25π / 6 in this embodiment. By setting the phase deviation, the peak value of the multi-frequency voltage can be reduced.

[0037] B. Controllable multi-frequency voltage generation: First, the first control system sends a first control signal, causing the AC-DC converter to convert the AC voltage into a set DC voltage. The first switch is closed, and the second control system sends a second control signal. This second control signal is obtained by performing carrier phase shift modulation (or other multi-level modulation methods) on the multi-frequency voltage reference signal, causing the voltage source H-bridge group to output a controlled multi-frequency voltage. By adjusting the set DC voltage in the first control system, the amplitude of the multi-frequency voltage output by the device can be controlled. In this embodiment, it is 10V. By adjusting the frequency composition of the multi-frequency voltage reference signal, the amplitude of the multi-frequency voltage output by the device can be controlled. 、 、…、 , the frequency of the device outputting multi-frequency voltage is controllable. In this embodiment, it is set to 200Hz, 220Hz, 240Hz, 260Hz, 280Hz, and 300Hz, thereby obtaining a multi-frequency voltage with controllable amplitude and frequency, such as Figure 2 shown.

[0038] Use Figure 1 The device shown generates a multi-frequency current with a time domain amplitude of 10V, a frequency range of 200-300Hz, and a frequency interval of 20Hz. The specific method is: A. Multi-frequency current reference signal synthesis: The multi-frequency current reference signal is synthesized by the fourth control system, and its expression is: ,in: 、 、…、 The frequency composition of the multi-frequency current can be controlled by the operator according to the required frequency. In this embodiment, it is set to 200Hz, 220Hz, 240Hz, 260Hz, 280Hz, and 300Hz. 、 、…、 The phase of each frequency component of the multi-frequency current is set to 0, π / 6, 4π / 6, 9π / 6, 16π / 6, and 25π / 6 in this embodiment. By setting the phase deviation, the peak value of the multi-frequency current can be reduced.

[0039] B. Controllable multi-frequency current generation: First, the first control system sends a first control signal, so that the AC-DC converter converts the AC voltage into the set DC voltage. The second switch is closed, and the third control system sends a third control signal, so that the DCV-DCI converter converts the DC voltage into the set DC current. The fourth control system sends a fourth control signal, which is obtained by performing carrier phase shift modulation (or other multi-level modulation methods) on the multi-frequency current reference signal, so that the current source type H-bridge group outputs a controlled multi-frequency current. By adjusting the set DC current in the third control system, the amplitude of the multi-frequency current output by the device can be controlled. In this embodiment, it is 10A. By changing the frequency composition of the multi-frequency current reference signal 、 、…、 , the frequency of the device outputting multi-frequency current is controllable. In this embodiment, it is set to 200Hz, 220Hz, 240Hz, 260Hz, 280Hz, and 300Hz, thereby obtaining a multi-frequency current with controllable amplitude and frequency, such as Figure 3 shown.

[0040] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A multi-frequency harmonic generating device with voltage and current output ports, characterized in that: The device includes: Along the direction of multi-frequency voltage output, a voltage source, a transformer, an inductor, an AC / DC converter, a DC capacitor, a first switch and a voltage source type H-bridge group are sequentially connected to form a multi-frequency voltage output part; Along the direction of multi-frequency current output, a voltage source, a transformer, an inductor, an AC-DC converter, a DC capacitor, a second switch, a DCV-DCI converter and a current source type H-bridge group are connected in sequence to form a multi-frequency current output part; The AC / DC converter is controlled by a first control system, the voltage source H-bridge group is controlled by a second control system, the DCV-DCI converter is controlled by a third control system, and the current source H-bridge group is controlled by a fourth control system. The first control system adopts constant DC voltage control, the second control system adopts target multi-frequency voltage carrier phase-shift modulation, the third control system adopts constant DC current control, and the fourth control system adopts target multi-frequency current carrier phase-shift modulation.

2. The device according to claim 1, characterized in that The primary side of the transformer is connected to a voltage source, the secondary side of the transformer is connected to the inductor and then to the input side of the AC / DC converter, and the output side of the AC / DC converter is connected to the DC capacitor; The DC capacitor is connected in parallel with a first port and a second port. The first port is connected to the first switch and then to the input side of the voltage source H-bridge group. The output side of the voltage source H-bridge group is a multi-frequency voltage output port. The second port is connected to the second switch and then to the input side of the DCV-DCI converter. The output side of the DCV-DCI converter is connected to the input side of the current source H-bridge group. The output side of the current source H-bridge group is a multi-frequency current output port.

3. The device according to claim 2, characterized in that The first switch and the second switch are used for switching the multi-frequency voltage output part and the multi-frequency current output part.

4. The device according to claim 1, characterized in that The voltage source type H bridge group is composed of n voltage source type H bridges, the input side of which is n voltage source type H bridges connected in parallel, and the output side of which is n voltage source type H bridges connected in series; wherein n is a positive integer.

5. The device according to claim 1, characterized in that The current source type H bridge group is composed of n current source type H bridges, the input side of which is n current source type H bridges connected in parallel, and the output side of which is n current source type H bridges connected in series; wherein n is a positive integer.

6. The device according to claim 1, characterized in that The transformer is a step-down transformer.

7. The device according to claim 1, characterized in that The voltage source is an AC voltage source.

8. A method for generating multi-frequency harmonics using a multi-frequency harmonics generating device having a voltage and current output port according to any one of claims 1 to 7, characterized in that: Methods include: Outputting a first control signal through a first control system causes the AC / DC converter to convert an AC voltage into a DC voltage, closing the first switch, and outputting a second control signal through a second control system causes the voltage source H-bridge group to output a controlled multi-frequency voltage; wherein the amplitude of the multi-frequency voltage output portion is controllable by adjusting the voltage of the first control signal output by the first control system, and the frequency of the multi-frequency voltage output portion is controllable by adjusting the frequency component of the second control signal output by the second control system, thereby obtaining a multi-frequency voltage with controllable amplitude and frequency; A first control signal is output through the first control system, causing the AC-DC converter to convert the AC voltage into a DC voltage and close the second switch. A third control signal is output through the third control system, causing the DCV-DCI converter to convert the DC voltage into a DC current. A fourth control signal is output through the fourth control system, causing the current source H-bridge group to output a controlled multi-frequency current. The amplitude of the multi-frequency current output portion is controllable by adjusting the current magnitude of the third control signal output by the third control system, and the frequency component of the fourth control signal output by the fourth control system is adjusted to achieve controllable frequency of the multi-frequency current output, thereby obtaining a multi-frequency current with controllable amplitude and frequency.

9. The method according to claim 8, characterized in that The expression of the second control signal output by the second control system is: ,in, 、 、…、 The frequency composition of the multi-frequency voltage, 、 、…、 is the phase of each frequency component of the multi-frequency voltage.

10. The method according to claim 8, characterized in that The expression of the fourth control signal output by the fourth control system is: ;in, 、 、…、 is the frequency component of the multi-frequency current, 、 、…、 is the phase of each frequency component of the multi-frequency current.

Images