Modularized combined type large-capacity power grid simulation device

Abstract

The utility model discloses a modularized combined large-capacity power grid simulation device, which comprises an input transformer, N disturbance voltage generation modules and an output filter capacitor, and is characterized in that the output end of the input transformer is connected with the input ends of the N disturbance voltage generation modules; each disturbance voltage generation module comprises a rectifier, an inverter and an output transformer which are connected in sequence; the output end of each rectifier is connected with the input end of the corresponding inverter; each of the inverters comprises two three-phase inverters; according to the device, a plurality of modularized disturbance voltage generation modules output series combination to realize capacity improvement, the design of each disturbance voltage generation module is simplified, meanwhile, the output equivalent switching frequency can be improved through series combination, different voltage combination output can be realized through configuration of a plurality of taps, the output voltage performance of the device is more excellent, and the device is suitable for large-scale popularization and application. The device is especially suitable for an application occasion that a power grid simulation device carries a large-capacity tested device.

Description

Technical Field

[0001] The utility model relates to the technical field of new energy power generation equipment testing, in particular to a modular combined large-capacity power grid simulation device. Background Technique

[0002] With the wide application of new energy power generation equipment, in order to improve power supply reliability, it is objectively required that new energy power generation equipment has strong power grid adaptability. Under this background, it is very necessary to develop supporting testing technologies to carry out the testing and research on the grid-connected working characteristics of new energy power generation equipment.

[0003] The existing testing technologies generally use power grid simulation devices to test the grid-connected working characteristics of new energy power generation equipment, including power grid adaptability, power quality adaptability, high and low voltage ride-through capabilities, etc.

[0004] In the prior art, the single-machine capacity of power grid simulation devices is generally in the range of several hundred kVA to 10 MVA. In applications with larger capacities, a multi-machine parallel scheme needs to be adopted. When applied in parallel, the power grid simulation device has high requirements for transient voltage synchronization, complex control, cannot increase the output equivalent switching frequency, cannot achieve different voltage combination outputs, and the output voltage of the device is single. Content of the Utility Model

[0005] The technical problem to be solved by the utility model is to provide a modular combined large-capacity power grid simulation device. The modular combined large-capacity power grid simulation device realizes capacity improvement through the series combination of outputs of multiple modular disturbance voltage generation modules, simplifies the design of each disturbance voltage generation module, and at the same time can increase the output equivalent switching frequency through series combination. By configuring multiple tap changers, different voltage combination outputs can be achieved, and the output voltage performance of the device is more excellent, which is especially suitable for the application occasions where the power grid simulation device loads large-capacity equipment under test.

[0006] To solve the above technical problems, the present utility model provides a modular combined large-capacity power grid simulation device, which includes an input transformer, N disturbance voltage generation modules, and output filter capacitors. The output end of the input transformer is connected to the input ends of the N disturbance voltage generation modules. Each of the disturbance voltage generation modules includes a rectifier, an inverter, and an output transformer connected in sequence. The output ends of each rectifier are connected to the input ends of the corresponding inverter. Each of the inverters includes two three-phase inverters, and each of the output transformers includes three single-phase transformers. The same-phase output ends of the two three-phase inverters are correspondingly connected to the primary windings of a single-phase transformer. Each of the secondary windings of the single-phase transformers is provided with M voltage regulating taps. One end of the secondary windings of the single-phase transformers corresponding to each phase in all the disturbance voltage generation modules serves as the corresponding phase output end of the device and is connected to the three-phase input ends of the output filter capacitors. A group of voltage regulating taps with the same group number are selected from the secondary windings of the single-phase transformers corresponding to each phase in all the disturbance voltage generation modules and are connected in series with each other, and the three ends formed by the corresponding voltage regulating taps connected in series with each other are short-circuited with each other to form a star connection and are connected to the midpoint of the output filter capacitors. Among them, N≥2, M≥1.

[0007] Preferably, both the rectifier and the inverter adopt two-level converters or multi-level converters.

[0008] Preferably, the input transformer includes a primary three-phase winding and N secondary three-phase windings, and each of the secondary three-phase windings is connected to a rectifier in a corresponding disturbance voltage generation module.

[0009] Preferably, the input transformer includes N three-phase transformers, the primary windings of the N three-phase transformers are connected in parallel, and the secondary winding of each three-phase transformer is connected to a rectifier in a corresponding disturbance voltage generation module.

[0010] Preferably, each of the disturbance voltage generation modules further includes a bypass switch corresponding to each of the single-phase transformers, and the bypass switch is connected in parallel with the secondary winding of the corresponding single-phase transformer in the disturbance voltage generation module.

[0011] Preferably, when any one of the disturbance voltage generation modules in the modular combined large-capacity power grid simulation device fails, the corresponding bypass switch in the failed disturbance voltage generation module is closed online, and the remaining N-1 disturbance voltage generation modules operate normally.

[0012] Preferably, the modular combined large-capacity power grid simulation device further includes a master controller and sub-controllers provided in each of the disturbance voltage generation modules, and the sub-controllers are communicatively connected to the corresponding inverters; the master controller and the sub-controllers cooperate to control the inverters to output fundamental voltage and harmonic voltage.

[0013] After adopting the above device, the modular combined large-capacity power grid simulation device includes an input transformer, N disturbance voltage generation modules, and output filter capacitors. The output end of the input transformer is connected to the input ends of the N disturbance voltage generation modules. Each of the disturbance voltage generation modules includes a rectifier, an inverter, and an output transformer connected in sequence; the output ends of the rectifiers are connected to the input ends of the corresponding inverters; each of the inverters includes two three-phase inverters, and each of the output transformers includes three single-phase transformers; the same-phase output ends of the two three-phase inverters are correspondingly connected to the primary windings of a single-phase transformer; each of the secondary windings of the single-phase transformers is provided with N - 1 voltage regulating taps; any of the taps with the same group number in the secondary windings of the single-phase transformers corresponding to each phase in all the disturbance voltage generation modules are connected in series, and one end is used as the corresponding phase output end of the device and is connected to the three-phase input ends of the output filter capacitors, and the other ends are short-circuited to form a star connection and are connected to the midpoint of the output filter capacitors; the modular combined large-capacity power grid simulation device realizes capacity improvement through the series combination output of multiple modular disturbance voltage generation modules, simplifies the design of each disturbance voltage generation module, and at the same time can improve the output equivalent switching frequency through the series combination. Different voltage combinations can be output by configuring multiple taps, and the output voltage performance of the device is more excellent, which is especially suitable for the application occasions where the power grid simulation device loads large-capacity devices under test. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is the overall circuit of a modular combined large-capacity power grid simulation device of the present invention Figure 1 ;

[0015] Figure 2 is the overall circuit of a modular combined large-capacity power grid simulation device of the present invention Figure 2 ;

[0016] Figure 3 is the circuit of the disturbance voltage generation module of a modular combined large-capacity power grid simulation device of the present invention Figure 1 ;

[0017] Figure 4 is the circuit of the disturbance voltage generation module of a modular combined large-capacity power grid simulation device of the present invention Figure 2 ;

[0018] Figure 5 This is the circuit diagram of the voltage regulating tap of the secondary winding of a single-phase transformer of a modular combined large-capacity power grid simulation device of the present utility model. Specific embodiments

[0019] In order to make the objectives, technical solutions and advantages of the present utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0020] Embodiment 1

[0021] Please refer to Figure 1 and Figure 5 , Figure 1 This is the overall circuit of a modular combined large-capacity power grid simulation device of the present utility model Figure 1 , Figure 5 This is the circuit diagram of the voltage regulating tap of the secondary winding of a single-phase transformer of a modular combined large-capacity power grid simulation device of the present utility model;

[0022] This embodiment discloses a modular combined large-capacity power grid simulation device, which includes an input transformer 10, N disturbance voltage generating modules 20, and an output filter capacitor 30. The output end of the input transformer 10 is connected to the input ends of the N disturbance voltage generating modules 20. Each of the disturbance voltage generating modules 20 includes a rectifier, an inverter, and an output transformer connected in sequence; the output ends of each rectifier are connected to the input ends of the corresponding inverters; each of the inverters includes two three-phase inverters, and each of the output transformers includes three single-phase transformers; the same-phase output ends of the two three-phase inverters are correspondingly connected to the primary winding of a single-phase transformer; M voltage regulating taps 21 are provided on the secondary winding of each single-phase transformer; one end of the secondary winding of the single-phase transformers corresponding to each phase in all the disturbance voltage generating modules 20 is used as the corresponding phase output end of the device and is connected to the three-phase input ends of the output filter capacitor 30. A group of voltage regulating taps 21 with the same group number are selected from the secondary windings of the single-phase transformers corresponding to each phase in all the disturbance voltage generating modules 20 and are connected in series with each other, and the three ends formed by the corresponding voltage regulating taps connected in series with each other are short-circuited to form a star connection and are connected to the midpoint of the output filter capacitor 30; wherein, N≥2, M≥1.

[0023] In this embodiment, after changing the voltage regulating taps with the same group number of the secondary winding of the single-phase transformer, the device can form M output voltages.

[0024] Embodiment 2

[0025] Please refer to Figure 3 ,Figure 3 The circuit of the disturbance voltage generation module of a modular combined large-capacity power grid simulation device of the present utility model Figure 2 ;

[0026] Based on Embodiment 1, in this embodiment, both the rectifier and the inverter adopt a two-level converter or a multi-level converter.

[0027] Embodiment 3

[0028] Please refer to Figure 1 , Figure 1 The overall circuit of a modular combined large-capacity power grid simulation device of the present utility model Figure 1 ;

[0029] Based on Embodiment 1, in this embodiment, the input transformer includes a primary three-phase winding and N secondary three-phase windings, and each of the secondary three-phase windings is connected to a rectifier in a corresponding disturbance voltage generation module.

[0030] Embodiment 4

[0031] Please refer to Figure 2 , Figure 2 The overall circuit of a modular combined large-capacity power grid simulation device of the present utility model Figure 2 ;

[0032] Based on Embodiment 1, in this embodiment, the input transformer includes N three-phase transformers, the primary windings of the N three-phase transformers are connected in parallel, and the secondary winding of each three-phase transformer is connected to a rectifier in a corresponding disturbance voltage generation module.

[0033] Embodiment 5

[0034] Please refer to Figure 4 , Figure 4 The circuit of the disturbance voltage generation module of a modular combined large-capacity power grid simulation device of the present utility model Figure 2 ;

[0035] Each of the disturbance voltage generation modules further includes a bypass switch corresponding to each of the single-phase transformers, and the bypass switch is connected in parallel with the secondary winding of the corresponding single-phase transformer in the disturbance voltage generation module.

[0036] In this embodiment, when any one of the disturbance voltage generation modules in the modular combined large-capacity power grid simulation device fails, the bypass switch corresponding to the failed disturbance voltage generation module is closed online, and the remaining N - 1 disturbance voltage generation modules operate normally.

[0037] Embodiment 6

[0038] This embodiment is based on Embodiment 1. In this embodiment, the modular combined large-capacity power grid simulation device further includes a main controller and sub-controllers arranged in each of the disturbance voltage generation modules. The sub-controllers are communicatively connected to the corresponding inverters; the main controller and the sub-controllers cooperate to control the inverters to output fundamental voltage and harmonic voltage.

[0039] The modular combined large-capacity power grid simulation device realizes capacity improvement through the series combination of the outputs of multiple modular disturbance voltage generation modules, simplifies the design of each disturbance voltage generation module. At the same time, the equivalent switching frequency of the output can be increased through series combination, and different voltage combinations can be output by configuring multiple tap changers. The output voltage performance of the device is more excellent, and it is especially suitable for the application occasion where the power grid simulation device loads a large-capacity device under test.

[0040] The preferred embodiments of the present application have been described above with reference to the accompanying drawings, but this does not limit the scope of the rights of the present application. Any modifications, equivalent replacements, and improvements made by those skilled in the art without departing from the scope and essence of the present application shall fall within the scope of the rights of the present application.

Claims

1. A modular combined large-capacity power grid simulation device, characterized in that: The invention comprises an input transformer, N disturbance voltage generating modules, and an output filter capacitor, wherein the output end of the input transformer is connected to the input end of the N disturbance voltage generating modules, and each of the disturbance voltage generating modules comprises a rectifier, an inverter, and an output transformer connected in sequence; the output end of each rectifier is connected to the corresponding input end of the inverter; each of the inverters comprises two three-phase inverters, and each of the output transformers comprises three single-phase transformers; the same phase output ends of the two three-phase inverters are correspondingly connected to the primary winding of a single-phase transformer; each of the single-phase transformers The secondary winding of the transformer is provided with M voltage regulating taps; one end of the secondary winding of each corresponding single-phase transformer in all the disturbance voltage generating modules is used as the corresponding phase output end of the device and is connected to the three-phase input end of the output filter capacitor; a group of voltage regulating taps with the same group number are selected from the secondary winding of each corresponding single-phase transformer in all the disturbance voltage generating modules and are connected in series with each other, and the three ends formed by the series connection of each corresponding voltage regulating tap are short-circuited to form a star connection and are connected to the midpoint of the output filter capacitor; wherein, N≥2, M≥1.

2. The modular combined large-capacity power grid simulation device according to claim 1 is characterized in that: The rectifier and the inverter both adopt two-level converters or multi-level converters.

3. The modular combined large-capacity power grid simulation device according to claim 1 is characterized in that: The input transformer includes a primary three-phase winding and N secondary three-phase windings, and each of the secondary three-phase windings is connected to a corresponding rectifier in the disturbance voltage generating module.

4. The modular combined large-capacity power grid simulation device according to claim 1 is characterized in that: The input transformer comprises N three-phase transformers, the primary windings of the N three-phase transformers are connected in parallel, and the secondary winding of each three-phase transformer is connected to a corresponding rectifier in the disturbance voltage generating module.

5. The modular combined large-capacity power grid simulation device according to claim 1, characterized in that: Each of the disturbance voltage generating modules further includes a bypass switch corresponding to each of the single-phase transformers, and the bypass switch is connected in parallel with the secondary winding of the corresponding single-phase transformer in the disturbance voltage generating module.

6. The modular combined large-capacity power grid simulation device according to claim 5, characterized in that: When any of the disturbance voltage generating modules in the modular combined large-capacity power grid simulation device fails, the corresponding bypass switch in the failed disturbance voltage generating module is closed online, and the remaining N-1 disturbance voltage generating modules operate normally.

7. The modular combined large-capacity power grid simulation device according to claim 1, characterized in that: The modular combined large-capacity power grid simulation device also includes a main controller and a sub-controller arranged in each of the disturbance voltage generating modules, and the sub-controller is communicatively connected with the corresponding inverter; the main controller and the sub-controller cooperate to control the inverter to output the fundamental voltage and subharmonic voltage.

Images