CN201234142Y - Bus control apparatus for solar photovoltaic grid connection DC-to-AC converter - Google Patents

Abstract

The utility model discloses a solar photovoltaic grid-connected inverter busbar control device, which comprises a booster circuit, a busbar circuit, an inverter bridge circuit, a filter circuit, a sampling circuit and a control circuit. The booster circuit is electrically connected to the busbar circuit, and the busbar The circuit is electrically connected to the inverter bridge circuit, and the inverter bridge circuit is electrically connected to the filter circuit. The voltage signal of the bus circuit is sampled by the sampling circuit and sent to the control circuit, and the boost circuit is controlled by the control circuit. The utility model changes the state that the busbar voltage works at a fixed voltage value, so that the voltage value can be adjusted in real time with the grid voltage fluctuation, so that when the external grid voltage is low, the self-loss of the inverter is small, and the output current harmonics are lower.

Description

Solar photovoltaic grid-connected inverter busbar control device

technical field

The utility model relates to a solar photovoltaic grid-connected inverter, in particular to a solar photovoltaic grid-connected inverter bus bar control device.

Background technique

At present, the busbar voltage in the solar photovoltaic grid-connected inverter is always designed to be stable at a specific voltage during design, and does not change with the external grid voltage, resulting in increased self-loss of the inverter when the external grid voltage is low, and the output Current harmonics are high.

Contents of the invention

The purpose of this utility model is to overcome the deficiencies of the prior art and provide a solar energy inverter that can change with the voltage of the external grid, so that when the voltage of the external grid is low, the self-loss of the inverter is small and the harmonics of the output current are lower. Photovoltaic grid-connected inverter busbar control device.

The technical solution to achieve the above purpose is: a solar photovoltaic grid-connected inverter busbar control device, the improvement of which is that it includes a booster circuit, a busbar circuit, an inverter bridge circuit, a filter circuit, a sampling circuit and a control circuit. The circuit is electrically connected to the bus circuit, the bus circuit is electrically connected to the inverter bridge circuit, the inverter bridge circuit is electrically connected to the filter circuit, the voltage signal of the bus circuit is sampled by the sampling circuit and sent to the control circuit, and the boost circuit is controlled by the control circuit .

The utility model changes the state that the busbar voltage works at a fixed voltage value in the prior art, so that the busbar voltage value can be adjusted in real time with the fluctuation of the grid voltage, so that when the external grid voltage is low, the loss of the inverter itself is small, and the output current is harmonious. The waves are lower. Because the control circuit can change the output voltage of the booster circuit with the change of the external network voltage, the filter circuit can filter the inverter output current, so that the output current harmonic can reach the required value.

Description of drawings

Fig. 1 is the use block diagram of the utility model;

Fig. 2 is a circuit diagram of the embodiment.

Detailed ways

Below in conjunction with accompanying drawing, the utility model is further described.

Referring to Figures 1 and 2, a solar photovoltaic grid-connected inverter busbar control device includes a booster circuit 2, a busbar circuit 3, an inverter bridge circuit 4, a filter circuit 5, a sampling circuit 7 and a control circuit 8, and the booster circuit 2 is electrically connected to the bus circuit 3, the bus circuit 3 is electrically connected to the inverter bridge circuit 4, the inverter bridge circuit 4 is electrically connected to the filter circuit 5, the voltage signal of the bus circuit 3 is sent to the control circuit 8 after being sampled by the sampling circuit 7, And the boost circuit 2 is controlled by the control circuit 8 . The booster circuit 2 is externally connected to the solar battery 1, the filter circuit 5 is connected to the external grid 6 through the relay switches S1 and S2, the voltage signal of the external grid 6 is sampled by the sampling circuit 7 and then sent to the control circuit 8, and the booster circuit 2 is controlled by the control circuit 8 to the required bus voltage value.

The boost circuit 2 includes an inductor L1, a field effect transistor Q1, and diodes D0 and D1. The bus circuit 3 includes capacitors C1 and C2. One end of the inductor L1 in the boost circuit 2 is the positive input end of the power supply, and the end of the inductor L1 is The other end is electrically connected to one end of the circuit connected in parallel by the field effect transistor Q1 and the diode D1, and the other end of the circuit connected in parallel by the field effect transistor Q1 and the diode D1 is connected to the circuit connected in parallel by the capacitors C1 and C2 in the bus circuit 3 One end of the circuit is connected and connected to the negative input terminal of the power supply, and a diode is connected in series between one end of the circuit connected in parallel with the field effect transistor Q1 and the diode D1 and the other end of the circuit connected in parallel with the capacitors C1 and C2 in the bus circuit 3 D0.

The inverter bridge circuit 4 includes field effect transistors Q2, Q3, Q4, Q5 and diodes D2, D3, D4, D5, the diode D2 is connected in parallel with the field effect transistor Q2, the diode D3 is connected in parallel with the field effect transistor Q3, and the diode D4 is connected in parallel with the field effect transistor Q3. The effect transistor Q4 is connected in parallel, the diode D5 is connected in parallel with the FET Q5, and the parallel circuit of the FET Q2 and the diode D2 is connected in series with the parallel circuit of the FET Q4 and the diode D4, and then connected in parallel with the capacitor C3, and the FET Q3 and the diode The parallel circuit of D3 is connected in parallel with the capacitor C3 after being connected in series with the parallel circuit of field effect transistor Q5 and diode D5.

The filter circuit 5 includes inductors L2 , L3 and a capacitor C4 , and the input end of the filter circuit 5 is connected to the output end of the inverter bridge circuit 4 .

The sampling circuit 7 uses a common resistance voltage division sampling circuit.

The controller adopted by the control circuit 8 may be a digital signal processor or a single-chip microcomputer or other microprocessors. The TI2407 digital signal processor (DSP) of TI Company is used in this embodiment. The control circuit 8 is composed of a TI2407 digital signal processor and a published standard peripheral circuit provided by TI company, and the TI2407 digital signal processor is available in the market.

When the utility model is in use, by continuously sampling and detecting the voltage V1 of the external grid 6, the fluctuation of the grid voltage is detected in real time, and the output boost is adjusted according to the sampled bus voltage through feedback to the control circuit The duty cycle of the driving pulse width is used to determine different bus operating voltages, which improves the overall efficiency of the device and lowers the output current harmonics.

Claims (5)

1, a kind of solar photovoltaic interconnected inverter bus control device, it is characterized in that: comprise booster circuit (2), bus circuit (3), inverter bridge circuit (4), filter circuit (5), sample circuit (7) and control circuit (8), booster circuit (2) is electrically connected with bus circuit (3), bus circuit (3) is electrically connected with inverter bridge circuit (4), inverter bridge circuit (4) is electrically connected with filter circuit (5), the voltage signal of bus circuit (3) is given control circuit (8) after sample circuit (7) sampling, and by control circuit (8) control booster circuit (2).

2, solar photovoltaic interconnected inverter bus control device according to claim 1, it is characterized in that: described booster circuit (2) comprises inductance L 1, field effect transistor Q1 and diode D0, D1, described bus circuit (3) comprises capacitor C 1, C2, one end of the inductance L 1 in the booster circuit (2) is the power supply positive input terminal, the other end of inductance L 1 is electrically connected with a end by the circuit after field effect transistor Q1 and the diode D1 parallel connection, be connected and be connected to the power-input by the end in the other end of the circuit after field effect transistor Q1 and the diode D1 parallel connection and the bus circuit (3), by being serially connected with diode D0 between the other end of the circuit after in parallel in an end of the circuit after field effect transistor Q1 and the diode D1 parallel connection and the bus circuit (3) by capacitor C 1 and C2 by the circuit after capacitor C 1 and the C2 parallel connection.

3, solar photovoltaic interconnected inverter bus control device according to claim 1 and 2, it is characterized in that: described inverter bridge circuit (4) comprises field effect transistor Q2, Q3, Q4, Q5 and diode D2, D3, D4, D5, diode D2 is in parallel with field effect transistor Q2, diode D3 is in parallel with field effect transistor Q3, diode D4 is in parallel with field effect transistor Q4, diode D5 is in parallel with field effect transistor Q5, and the parallel circuits of field effect transistor Q2 and diode D2 is with in parallel with capacitor C 3 again after the parallel circuits of field effect transistor Q4 and diode D4 is connected, and the parallel circuits of field effect transistor Q3 and diode D3 is with also in parallel with capacitor C 3 after the parallel circuits of field effect transistor Q5 and diode D5 is connected.

4, solar photovoltaic interconnected inverter bus control device according to claim 1 and 2, it is characterized in that: described filter circuit (5) comprises inductance L 2, L3 and capacitor C 4, and the input of filter circuit (5) is connected with the output of inverter bridge circuit (4).

5, solar photovoltaic interconnected inverter bus control device according to claim 1 and 2 is characterized in that: the controller that control circuit (8) adopts can also can be single-chip microcomputer for digital signal processor.

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