Alternating current component and direct current component sampling circuit for inverter

Abstract

The utility model discloses an alternating-current component and direct-current component sampling circuit for an inverter, and belongs to the technical field of inverters. Comprising a first gating module, a second gating module, a third gating module and a control module, the three input ends of the first gating module are respectively connected with the output ends of the three sampling modules of the inverter GRID current; the three input ends of the second gating module are respectively connected with the output ends of the three sampling modules of the inverter BACKUP voltage; two input ends of the third gating module are respectively connected with the output ends of the first gating module and the second gating module, and the output ends select one of the output ends to output according to a third gating signal and are simultaneously connected with subsequent power frequency filtering and amplifying circuits in sequence; and the control module is connected with the first gating module, the second gating module and the third gating module. According to the utility model, by introducing the gating module, circuit multiplexing is realized, the direct-current component sampling circuit can be greatly simplified, and the sampling precision is not influenced.

Description

Technical Field

[0001] This utility model relates to the field of inverter technology, and in particular to an AC DC component sampling circuit for inverters. Background Technology

[0002] Photovoltaic energy storage inverters operate in two modes: grid-connected and off-grid. Figure 1 As shown in the diagram, if the DC component of the grid-connected AC current and the DC component of the off-grid output AC voltage exceed regulatory limits, they may cause damage to downstream electrical equipment, transformers, motors, etc. Therefore, sampling the DC component is crucial for inverters.

[0003] Traditional three-phase energy storage inverter sampling circuits require six DC component sampling circuits, such as Figure 2 As shown, the following ports are required: Current_grid_L1, Current_grid_L2, Current_grid_L3, Voltage_backup_L1, Voltage_backup_L2, and Voltage_backup_L3. Each port requires an independent DC component sampling module, power frequency filtering, and amplification circuit, resulting in complex circuitry and a large amount of redundancy. Utility Model Content

[0004] To address the shortcomings of existing technologies, and considering that the DC component period is 50Hz, when the sampling frequency is much higher than the DC component period, the DC component sampling circuit can be greatly simplified by using a multiplexing circuit without affecting the sampling accuracy.

[0005] To achieve the above objectives, this utility model provides an AC DC component sampling circuit for an inverter, comprising: a first gating module, a second gating module, a third gating module, and a control module;

[0006] The three input terminals of the first gating module are respectively connected to the output terminals of the three sampling modules of the inverter GRID current, and the output terminal selects one of them to output according to the first gating signal;

[0007] The three input terminals of the second gating module are respectively connected to the output terminals of the three sampling modules of the inverter BACKUP voltage, and the output terminal selects one of them to output according to the second gating signal;

[0008] The two input terminals of the third gating module are respectively connected to the output terminals of the first gating module and the second gating module. The output terminal selects one of them according to the third gating signal and is connected to the subsequent power frequency filtering and amplification circuit in sequence.

[0009] The control module is connected to the first gating module, the second gating module, and the third gating module, and outputs the first gating signal, the second gating signal, and the third gating signal.

[0010] Furthermore, the control module is an MCU.

[0011] This utility model also provides an AC DC component sampling circuit for an inverter, including: a gating module and a control module;

[0012] The gating module includes six input ports and one output port. It selects one of the six input ports and outputs it to the output port according to the gating signal.

[0013] The input ports of the gating module are respectively connected to the output terminals of the three sampling modules of the inverter GRID current and the three sampling modules of the inverter BACKUP voltage, and the output ports are sequentially connected to the subsequent power frequency filtering and amplification circuits.

[0014] The control module is connected to the gating module and outputs a gating signal.

[0015] Furthermore, the control module is an MCU.

[0016] The beneficial effects of this utility model are:

[0017] This invention introduces a gating module and uses time-division multiplexing to sample the DC component of the inverter. It can achieve sampling using only one set of power frequency filtering and amplification circuits, which greatly simplifies the DC component sampling circuit and reduces the hardware circuit from 6 channels to 1 channel. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a photovoltaic energy storage inverter according to an embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram of the DC component sampling circuit structure of a conventional photovoltaic energy storage inverter, as described in an embodiment of this utility model.

[0020] Figure 3 This is a schematic diagram of the AC-DC component sampling circuit (Circuit 1) used in an inverter according to an embodiment of this utility model.

[0021] Figure 4 This is a schematic diagram of the AC-DC component sampling circuit (circuit two) used in an inverter according to an embodiment of this utility model. Detailed Implementation

[0022] The present invention will be further explained and described below with reference to the accompanying drawings and embodiments.

[0023] like Figure 3As shown, this utility model provides an AC-DC component sampling circuit for an inverter, comprising: a first gating module, a second gating module, a third gating module, and a control module. The first and second gating modules are 3-to-1 gating chips, the third gating module is a 2-to-1 gating chip, and the control module is an MCU.

[0024] The three input terminals of the first gating module are respectively connected to the output terminals of the three sampling modules of the inverter GRID current, and the output terminal selects one of them to output according to the first gating signal.

[0025] The three input terminals of the second gating module are respectively connected to the output terminals of the three sampling modules of the inverter BACKUP voltage, and the output terminal selects one of them to output according to the second gating signal.

[0026] The two input terminals of the third gating module are connected to the output terminals of the first gating module and the second gating module, respectively. The output terminal selects one of the outputs according to the third gating signal and connects to the subsequent power frequency filtering and amplification circuits in sequence.

[0027] The control module is connected to the first gating module, the second gating module, and the third gating module, and outputs the first gating signal, the second gating signal, and the third gating signal.

[0028] Its working principle is as follows:

[0029] For energy storage inverters, the sampling of the DC components of the grid current and backup voltage is time-division multiplexing. That is, in grid-connected mode, only the DC component of the grid current needs to be collected; in off-grid mode, only the DC component of the backup voltage needs to be collected. Therefore, different groups of DC component sampling can be achieved through a 2-to-1 selection chip.

[0030] When entering grid-connected mode, the MCU controls a 3-to-1 selector chip, controlling the frequency to sequentially select the GRID L1 / 2 / 3 current signals to enter the power frequency filtering and amplification circuit, thereby achieving sampling of the DC component of the GRID current. Furthermore, since the MCU control frequency is typically no lower than 1kHz, far exceeding the power frequency of 50Hz, this scheme does not affect sampling accuracy.

[0031] Similarly, when entering off-grid mode, the MCU uses the same strategy to sequentially select the BACKUP L1 / 2 / 3 voltage signals to enter the power frequency filtering and amplification circuit, thereby realizing the sampling of the DC component of the BACKUP voltage.

[0032] This invention also provides an AC-DC component sampling circuit for an inverter, which further simplifies the gating module and includes a gating module and a control module. The gating module is a 6-to-1 gating chip, including six input ports and one output port. It selects one input signal from the six input ports and outputs it to the output port according to the gating signal. The control module is an MCU.

[0033] The input ports of the gating module are connected to the outputs of the three sampling modules of the inverter GRID current and the three sampling modules of the inverter BACKUP voltage, respectively. The output ports are connected to the subsequent power frequency filtering and amplification circuits in sequence.

[0034] The control module is connected to the gating module and outputs a gating signal.

[0035] Its working principle is the same as above, and will not be repeated here.

[0036] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A current quantity direct current component sampling circuit for an inverter, characterized by, The application relates to a current and voltage sampling circuit for an inverter, which comprises a first gating module, a second gating module, a third gating module and a control module. Three input ends of the first gating module are connected with the output ends of three sampling modules of an inverter GRID current, and an output end selects one output according to a first gating signal; Three input ends of the second gating module are connected with the output ends of three sampling modules of an inverter BACKUP voltage, and an output end selects one output according to a second gating signal; Two input ends of the third gating module are connected with the output ends of the first gating module and the second gating module, an output end selects one output according to a third gating signal, and the output end is sequentially connected with a subsequent power frequency filtering and amplifying circuit; The control module is connected with the first gating module, the second gating module and the third gating module, and outputs the first gating signal, the second gating signal and the third gating signal. The control module is an MCU.

2. The ac-dc component sampling circuit for an inverter of claim 1, wherein: The application relates to a current and voltage sampling circuit for an inverter, which comprises a gating module and a control module.

3. A current quantity DC component sampling circuit for an inverter, characterized by The gating module comprises six input ports and one output port, and an input signal in the six input ports is selected and output to the output port according to a gating signal; The input ports of the gating module are connected with the output ends of three sampling modules of an inverter GRID current and the output ends of three sampling modules of an inverter BACKUP voltage, and the output port is sequentially connected with a subsequent power frequency filtering and amplifying circuit; The control module is connected with the gating module and outputs the gating signal. The control module is an MCU. ​ 4. The ac-dc component sampling circuit for an inverter of claim 3, wherein: ​

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