CN219833780U - Double-circuit mppt non-isolated grid-connected photovoltaic inverter with low bypass loss - Google Patents

Abstract

The utility model relates to a double-circuit mppt non-isolated grid-connected photovoltaic inverter with low bypass loss, which comprises a photovoltaic group string, a Boost circuit and an inverter circuit, wherein the photovoltaic group string is transmitted to the Boost circuit through a bus, the Boost circuit comprises a Boost1 circuit, a Boost2 circuit, a first bypass and a second bypass, the bus comprises a bus1+ circuit, a bus2+ circuit and a bus-circuit, the Boost circuit boosts the input voltage of the photovoltaic group string into direct current inverter bus voltage, the boosted direct current is transmitted to the inverter circuit through the bus1+ circuit, the bus2+ circuit and the bus-circuit, the inverter circuit converts the boosted direct current into alternating current, the alternating current is filtered by a filter circuit and is then merged into a power grid, and when the voltage of the input direct current is higher than the direct current inverter bus voltage, the Boost1 circuit and the Boost2 circuit do not work, and the voltage of the input direct current is directly transmitted to the bus.

Description

Double-circuit mppt non-isolated grid-connected photovoltaic inverter with low bypass loss

Technical Field

The utility model belongs to the field of photovoltaic inverters, and particularly relates to a double-path mppt non-isolated grid-connected photovoltaic inverter with low bypass loss.

Background

As shown in fig. 1, the dual-channel mppt non-isolated grid-connected photovoltaic inverter with low bypass loss can invert and integrate direct current of a photovoltaic string into a power grid, and comprises a voltage boosting circuit, an inverter circuit and a filter circuit, wherein the photovoltaic circuit transmits direct current to the voltage boosting circuit, the voltage boosting circuit transmits direct current boosted by the inverter circuit, the inverter circuit converts the boosted direct current into alternating current, and the alternating current is filtered by the filter circuit and then integrated into the power grid.

However, the current grid-connected photovoltaic inverter does not consider the larger power consumption loss which can be caused to bypass diodes in a circuit when the current is too large.

Disclosure of Invention

The utility model aims to design a double-path mppt non-isolated grid-connected photovoltaic inverter with low bypass loss so as to realize the protection of a bypass in a booster circuit from being damaged by excessive current.

The specific technical scheme of the utility model is as follows: the utility model provides a low bypass loss's double-circuit mppt non-isolated grid-connected photovoltaic inverter, includes photovoltaic group cluster, boost circuit, inverter circuit, its characterized in that, photovoltaic group cluster is through bus transmission give Boost circuit direct current, boost circuit includes Boost1 circuit, boost2 circuit and respectively with Boost1 circuit, boost2 circuit connected first bypass and second bypass, the bus includes bus1+ circuit and bus2+ circuit and bus-circuit, boost circuit is photovoltaic input voltage is the direct current contravariant bus voltage, and through bus1+ circuit and bus2+ circuit and bus-circuit is the direct current electricity after the Boost is given inverter circuit, inverter circuit is the direct current after the Boost is converted into alternating current, and the alternating current is higher than direct current bus voltage after the voltage of input direct current, bus1+ circuit and bus2+ circuit are with Boost1 and second bypass direct current and bypass input voltage is passed through bus1 and second bypass direct current bypass.

When the voltage of the input direct current is lower than the voltage of the direct current inversion bus, the Boost1 circuit and the Boost2 circuit work simultaneously, the voltage of the input direct current is raised to the voltage of the bus, at the moment, the Boost1 circuit and the Boost2 circuit respectively carry out MPPT on respective input group strings, when the voltage of the input direct current is higher than the voltage of the direct current inversion bus, the Boost1 circuit and the Boost2 circuit do not work, and the voltage of the input direct current is directly sent to the bus, at the moment, two groups of input direct currents are forced to be connected in parallel, and the MPPT is carried out on the whole system through the inverter circuit.

As a further improvement, the intelligent power supply circuit further comprises a controller and an IGBT driver, wherein a first relay circuit is connected in parallel to the first bypass, a second relay circuit is connected in parallel to the second bypass, when the input current is overlarge, the first relay circuit and the second relay circuit are used for protecting the first bypass and the second bypass respectively, the controller transmits PWM1 signals to the first relay circuit and the IGBT driver, the controller transmits PWM2 signals to the second relay circuit and the IGBT driver, the IGBT driver converts the PWM1 signals and the PWM2 signals into boost1 signals and boost2 signals, and the IGBT driver transmits the boost1 signals to the boost1 circuits and transmits the boost2 signals to the boost2 circuits.

As a further improvement, the first relay circuit and the second relay circuit include a level smoother, a relay drive circuit, and a relay.

As a further improvement, the level smoother converts the boost signal from a high frequency signal to a low frequency boost signal to output to the relay drive circuit.

As a further improvement, the relay driving circuit transmits a signal to the relay to control the switching of the relay.

As a further improvement, the level smoother includes a diode D3, a resistor R1, a resistor R2, a resistor R3, and a capacitor C3.

As a further improvement, the relay driving circuit includes a transistor Q1, a resistor R4, a resistor R5, a diode D4, and a transistor Q2.

As a further improvement, the first bypass comprises a diode D1, the second bypass comprises a diode D2, the Boost1 circuit comprises an inductance L1, a diode D3, a first IGBT and a capacitor C1, and the Boost2 circuit comprises an inductance L2, a diode D4, a second IGBT and a capacitor C2.

Compared with the existing double-path MPPT non-isolated grid-connected photovoltaic inverter, the utility model has the advantages that the relay control circuit is added, the bypass is protected, and the bypass is prevented from being burnt due to overlarge circuit.

Drawings

FIG. 1 is a schematic diagram of a dual-path mppt non-isolated grid-tied photovoltaic inverter with low bypass loss according to the present utility model;

FIG. 2 is a schematic diagram of a photovoltaic string and boost circuit of a dual-path mppt non-isolated grid-connected photovoltaic inverter with low bypass loss according to the present utility model;

FIG. 3 is a schematic diagram of a boost circuit of a dual-path mppt non-isolated grid-connected photovoltaic inverter with low bypass loss;

FIG. 4 is a circuit diagram of a boost circuit of a dual-path mppt non-isolated grid-connected photovoltaic inverter with low bypass loss;

FIG. 5 is a circuit diagram of a relay control circuit of a dual-path mppt non-isolated grid-connected photovoltaic inverter with low bypass loss;

reference numerals illustrate: 1. boost circuit 2, boost1 circuit 3, boost2 circuit 4, first bypass 5, second bypass 6, busbar 7, level smoother 8, relay drive circuit 9, relay 13, first IGBT14, second IGBT.

Detailed Description

Embodiments of the present utility model will be described in detail below with reference to the accompanying drawings and examples.

Referring to fig. 1, the circuit shown in the figure includes a photovoltaic string, a boost circuit 1, an inverter circuit, a filter circuit and a power grid, referring to fig. 2, the boost circuit includes a boost1 circuit 2 and a boost2 circuit 3, the photovoltaic string is transmitted to the boost1 circuit 2 and the boost2 circuit 3 of the boost circuit 1 through a bus1+ circuit, a bus2+ circuit and a bus-circuit, the boost circuit 1 boosts a photovoltaic input voltage into a dc inverter bus voltage, and the boosted dc power is transmitted to the inverter circuit through the bus1+ circuit, the bus2+ circuit and the bus-circuit, the inverter circuit converts the boosted dc power into an ac power, and the ac power is filtered by the filter circuit and then is transmitted to the power grid.

Referring to fig. 3, the boost circuit further includes a first bypass 4 and a second bypass 5 connected to the boost1 circuit 2 and the boost2 circuit 3, respectively, and as can be seen from fig. 2, the bus1+ and the bus2+ further transmit direct current to the first bypass and the second bypass, and there are two operation modes of the boost circuit, namely, a non-bypass mode: when the input direct-current voltage is lower than the direct-current inversion bus voltage, the two boost circuits work simultaneously to rise the input voltage to the direct-current inversion bus voltage, and at the moment, the two boost circuits respectively carry out MPPT on the respective input group strings. This is the case for dual MPPT operation. Bypass mode: the input dc voltage is higher than the dc inversion bus voltage, the boost circuit is bypassed (not operated), the 2 sets of input dc voltages are directly sent to the bus 6, at this time, the two sets of inputs are forced to be connected in parallel, and the whole system is subjected to MPPT through the inverter circuit. In this case, instead of the dual MPPT operation, only the single MPPT operation is required, and the determination of the voltage level is performed by sampling the voltages on the bus1+ circuit and the bus2+ circuit and transmitting the processed voltages to the controller.

The first bypass is connected with a first relay circuit in parallel 4, the second bypass is connected with a second relay circuit in parallel 5, the device further comprises a controller and an IGBT driver, when the input current is overlarge, the relay circuit protects diodes on the bypass, the controller transmits PWM1 signals to the first relay circuit and the IGBT driver, the controller transmits PWM2 signals to the second relay circuit and the IGBT driver, the IGBT circuit converts the PWM1 signals and the PWM2 signals into boost1 signals and boost2 signals, the IGBT driver transmits the boost1 signals to the boost1 circuit 2, and the IGBT driver transmits the boost2 signals to the boost2 circuit 3.

Referring to fig. 5, the relay circuit includes a level smoother 7, a relay drive circuit 8, and a relay 9. The level smoother comprises a diode D3, a resistor R1, a resistor R2, a resistor R3 and a capacitor C3, the level smoother converts a boost signal from a high-frequency signal to a low-frequency boost signal and outputs the low-frequency boost signal to the relay driving circuit, the relay driving circuit transmits the signal to the relay to control the switch of the relay, and the relay driving circuit 8 comprises a triode Q1, a resistor R4, a resistor R5, a diode D4 and a triode Q2.

Referring to fig. 4, the first bypass 4 includes a diode D1, the second bypass 5 includes a diode D2, the Boost1 circuit 2 includes an inductor L1, a diode D3, a first IGBT13 and a capacitor C1, and the Boost2 circuit 3 includes an inductor L2, a diode D4, a second IGBT14 and a capacitor C2.

The above examples are merely illustrative of the preferred embodiments of the present utility model and are not intended to limit the scope of the present utility model, and various modifications and improvements made by those skilled in the art to the technical solution of the present utility model should fall within the scope of protection defined by the claims of the present utility model without departing from the spirit of the present utility model.

Claims (9)

1. The utility model provides a low bypass loss's double-circuit mppt non-isolated grid-connected photovoltaic inverter, includes photovoltaic group cluster, boost circuit, inverter circuit, its characterized in that, photovoltaic group cluster is through bus (6) transmission give Boost circuit (1) direct current, boost circuit (1) include Boost1 circuit (2), boost2 circuit (3) and respectively with Boost1 circuit (2), first bypass (4) and second bypass (5) that Boost2 circuit (3) link to each other, bus (6) include bus1+ circuit and bus2+ circuit and bus-circuit, boost circuit (1) is with photovoltaic group cluster input voltage is direct current inverter bus voltage to pass through bus1+ circuit with bus2+ circuit and bus-circuit is with direct current after the Boost is transmitted to inverter circuit, the alternating current after the Boost is converted into alternating current, and the input is higher than direct current (4) through the filter circuit and the direct current (4) and the bypass (4) direct current (4) is not passed through bus1+ circuit and bus-2+ circuit.

2. The dual-channel MPPT non-isolated grid-connected photovoltaic inverter with low bypass loss according to claim 1, wherein when the voltage of the input direct current is lower than the voltage of the direct current inversion bus, the Boost1 circuit (2) and the Boost2 circuit (3) work simultaneously, when the voltage of the input direct current is increased to the voltage of the direct current inversion bus, the Boost1 circuit (2) and the Boost2 circuit (3) respectively carry out MPPT on respective input strings, when the voltage of the input direct current is higher than the voltage of the direct current inversion bus, the Boost1 circuit (2) and the Boost2 circuit (3) do not work, and when the voltage of the input direct current is directly sent to the bus (6), two groups of input direct current are forced to be connected in parallel, and the whole system is subjected to MPPT through the inverter circuit.

3. The low bypass loss two-way mppt non-isolated grid-connected photovoltaic inverter of claim 2, further comprising a controller and an IGBT driver, wherein a first relay circuit is connected in parallel to the first bypass (4), a second relay circuit is connected in parallel to the second bypass (5), the first and second relay circuits protect the first and second bypasses (4, 5) respectively when the input current is excessive, the controller transmits PWM1 signals to the first relay circuit and the IGBT driver, the controller transmits PWM2 signals to the second relay circuit and the IGBT driver, the IGBT driver converts PWM1 signals and PWM2 signals to boost1 signals and boost2 signals, and the IGBT driver transmits boost1 signals to boost1 circuits (2), and the IGBT driver transmits boost2 signals to boost2 circuits (3).

4. A low bypass loss two-way mppt non-isolated grid-connected photovoltaic inverter according to claim 3, characterized in that the first and second relay circuits comprise a level smoother (7), a relay drive circuit (8) and a relay (9).

5. The low bypass loss two-way mppt non-isolated grid-connected photovoltaic inverter of claim 4, wherein the level smoother (7) converts the boost signal from a high frequency signal to a low frequency boost signal and outputs the low frequency boost signal to the relay driving circuit (8).

6. The low bypass loss two-way mppt non-isolated grid-connected photovoltaic inverter of claim 4, wherein said relay driving circuit (8) transmits signals to said relay (9) controlling the switching of said relay (9).

7. The low bypass loss two-way mppt non-isolated grid-connected photovoltaic inverter of claim 4, wherein said level smoother (7) comprises diode D3, resistor R1, resistor R2, resistor R3 and capacitor C3.

8. The low bypass loss two-way mppt non-isolated grid-connected photovoltaic inverter of claim 4, wherein said relay driver circuit (8) comprises transistor Q1, resistor R4, resistor R5, diode D4 and transistor Q2.

9. A low bypass loss two-way mppt non-isolated grid-connected photovoltaic inverter according to claim 3, wherein said first bypass (4) comprises a diode D1, said second bypass (5) comprises a diode D2, said Boost1 circuit (2) comprises an inductance L1, a diode D3, a first IGBT (13) and a capacitor C1, and said Boost2 circuit (3) comprises an inductance L2, a diode D4, a second IGBT (14) and a capacitor C2.