H-bridge micro inverter grid-connected device

• US 9,190,920 B2
• Filed: 08/10/2012
• Issued: 11/17/2015
• Est. Priority Date: 03/15/2012
• Status: Active Grant

• Current Assignee: Dongsheng Yang, Guangru Zhang, Huaguang Zhang, Le Li, Northeastern University, Rijiang Wang, Wang Gang, Xinrui Liu, Yang Jiao, Yingchun Wang
• Original Assignee: Dongsheng Yang, Guangru Zhang, Huaguang Zhang, Le Li, Northeastern University, Rijiang Wang, Wang Gang, Xinrui Liu, Yang Jiao, Yingchun Wang
• Inventors: Zhang, Huaguang, Liu, Xinrui, Yang, Dongsheng, Zhang, Guangru, Wang, Gang, Li, Le, Wang, Yingchun, Wang, Rijiang, Jiao, Yang
• Primary Examiner(s): STERRETT, JEFFREY L
• Application Number:
  US13/571,628
• Publication Number:
  US 20130242617A1
• Time in Patent Office: 1,194 Days
• Field of Search: 363/17, 363/28, 363/37, 363/56.05, 363/58, 363/95, 363/96, 363/98, 363/132, 363/136
• US Class Current: 1/1
• CPC Class Codes: H02M 1/007 Plural converter units in cascade push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826
• CPC Class Codes: H02M 3/33573 Full-bridge at primary side of an isolation transformer
• CPC Class Codes: H02M 7/4807 having a high frequency intermediate AC stage
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers

Abstract

An H-bridge micro inverter grid-connected device is invented to solve the problem that failure of any photovoltaic panel on the existing solar photovoltaic system cascade can cause efficiency reduction of the whole photovoltaic panel module. The H-bridge micro inverter grid-connected device comprises a single-chip microcomputer controller, a CPLD controller, a MOSFET full-bridge circuit, a high-frequency transformer, a half-bridge rectifying circuit, an SCR full-bridge circuit and a filter circuit, wherein the MOSFET full-bridge circuit is in the full-bridge type, the high-frequency transformer is a single-phase transformer with a central tap, and the SCR full-bridge circuit is applied. The integral structure above is characterized by the decreasing number of components, the reduction of power switches, and the simplification of the control circuits and driving circuits, so as to decrease the number of full-control switch components, improve the system reliability and reduce the system costs.

Claims

1. An H-bridge micro inverter grid-connected device, comprising:

a PIC single-chip microcomputer controller processing and calculating collected signals;

a CPLD controller outputting pulse signals, wherein the pulse signals include two groups of SPWM waves and one group of PWM waves;

an MOSFET H full-bridge circuit inverting DC signals outputted by photovoltaic panels to high-frequency AC signals;

a high-frequency transformer boosting the voltage of the high-frequency AC signals inverted by the MOSFET H full-bridge circuit to the voltage which conforms to a grid-connected amplitude;

a half-bridge rectifying circuit converting output signals of the high-frequency transformer to half sine wave signals;

an SCR H full-bridge circuit converting the half sine wave signals outputted by the half-bridge rectifying circuit to sine wave signals which conform to grid requirements; and

a filter circuit filtering harmonic waves in the sine waves outputted by the SCR H full-bridge circuit and converting the output sine waves to sine waves which conform to grid requirements;

wherein the SPWM waves control the MOSFET H full bridge to generate the high-frequency AC signals, and the PWM waves control the SCR H full-bridge to convert the half sine wave signals outputted by the half-bridge rectifying circuit to the sine wave signals.

2. The H-bridge micro inverter grid-connected device as claimed in claim 1, wherein the MOSFET H full-bridge circuit comprises a MOSFET transistor H full-bridge circuit and protection circuits, wherein drain electrodes of a first MOSFET transistor and a third MOSFET transistor of the MOSFET transistor H full-bridge circuit are connected with a high voltage side of the photovoltaic panels, and source electrodes of a second MOSFET transistor and a fourth MOSFET transistor of the MOSFET transistor H full-bridge circuit are connected with a low voltage side of the photovoltaic panels;

a source electrode of the first MOSFET transistor is connected with a drain electrode of the second MOSFET transistor, and a source electrode of the third MOSFET transistor is connected with a drain electrode of the fourth MOSFET transistor.

3. The H-bridge micro inverter grid-connected device as claimed in claim 2, wherein each of the first to fourth MOSFET transistors of the MOSFET transistor H full-bridge circuit is provided with a protection circuit comprising a resistor, a capacitor and a diode, the resistor has one terminal is connected with one terminal of the capacitor in series, and a connection between the resistor and the capacitor is connected with a cathode of the diode;

the other terminal of the capacitor is connected with the drain electrode of the MOSFET transistor, and the other terminal of the resistor is connected with the source electrode of the MOSFET transistor and an anode of the diode.

4. The H-bridge micro inverter grid-connected device as claimed in claim 2, wherein one terminal of a primary coil of the high-frequency transformer is connected with a center node of a bridge arm formed by the first MOSFET transistor and the third MOSFET transistor, and the other terminal of the primary coil of the high-frequency transformer is connected with a center node of a bridge arm formed by the second MOSFET transistor and the fourth MOSFET transistor;

both terminals of a secondary coil of the high-frequency transformer are respectively connected with the half-bridge rectifying circuit, and a central tap of the secondary coil of the high-frequency transformer is connected with the SCR full-bridge circuit.

5. The H-bridge micro inverter grid-connected device as claimed in claim 4, wherein the half-bridge rectifying circuit comprises diodes and filter capacitors, one terminal of the secondary coil of the high-frequency transformer is connected with an anode of a first diode of the diodes, and the other terminal of the secondary coil of the high-frequency transformer is connected with an anode of a second diode of the diodes;

a cathode of the first diode is connected with one terminal of the first filter capacitor of the filter capacitors, and the other terminal of the first filter capacitor is connected with the central tap of the secondary coil of the high-frequency transformer;

a cathode of the second diode is connected with one terminal of a second filter capacitor of the filter capacitors, and the other terminal of the second filter capacitor is connected with the central tap of the secondary coil of the high-frequency transformer.

6. The H-bridge micro inverter grid-connected device as claimed in claim 4, wherein the SCR H full-bridge circuit comprises an SCR transforming bridge circuit having a plurality of thyristors;

anodes of both a first thyristor and a third thyristor of the thyristors are connected with cathodes of a first diode and a second diode in the half-bridge rectifying circuit, and a cathode of the first thyristor is connected with an anode of a second thyristor of the thyristors;

a cathode of the third thyristor is connected with an anode of a fourth thyristor of the thyristors, cathodes of the third thyristor and the fourth thyristor are connected with the central tap of the secondary coil of the high-frequency transformer.

7. The H-bridge micro inverter grid-connected device as claimed in claim 6, wherein each of the thyristors is provided with protection circuits comprising resistors and capacitors;

one terminal of a first resistor of the resistors and one terminal of a first capacitor of the capacitors are connected with the anode of the thyristor, and the other terminal of the first capacitor is connected with one terminal of a second resistor of the resistors;

the other terminal of the second resistor and one terminal of a second capacitor of the capacitors are connected with the cathode of the thyristor, the other terminal of the second capacitor is connected with a gate of the thyristor, and the other terminal of the first resistor and the gate of the thyristor are used as input terminals of voltage driving signals.

8. The H-bridge micro inverter grid-connected device as claimed in claim 6, wherein the filter circuit comprises a resistor, capacitors and an inductor, the connection between the first thyristor and the second thyristor is connected with one terminal of the inductor, and the other terminal of the inductor is connected with one terminal of a first capacitor, one terminal of a second capacitor and a grid;

the other terminal of the second capacitor is connected with one terminal of the resistor, and the other terminal of the resistor is connected with the other terminal of the first capacitor and the grid.

9. The H-bridge micro inverter grid-connected device as claimed in claim 1, wherein the half-bridge rectifying circuit comprises diodes and filter capacitors, one terminal of a secondary coil of the high-frequency transformer is connected with an anode of a first diode of the diodes, and the other terminal of the secondary coil of the high-frequency transformer is connected with an anode of a second diode of the diodes;

a cathode of the first diode is connected with one terminal of a first filter capacitor of the filter capacitors, and the other terminal of the first filter capacitor is connected with a central tap of the secondary coil of the high-frequency transformer;

a cathode of the second diode is connected with one terminal of a second filter capacitor of the filter capacitors, and the other terminal of the second filter capacitor is connected with the central tap of the secondary coil of the high-frequency transformer.

10. The H-bridge micro inverter grid-connected device as claimed in claim 1, wherein the SCR H full-bridge circuit comprises an SCR transforming bridge circuit having a plurality of thyristors;

anodes of both a first thyristor and a third thyristor of the thyristors are connected with cathodes of a first diode and a second diode in the half-bridge rectifying circuit, and a cathode of the first thyristor is connected with an anode of a second thyristor of the thyristors;

a cathode of the third thyristor is connected with an anode of a fourth thyristor of the thyristors, cathodes of the third thyristor and the fourth thyristor are connected with a central tap of a secondary coil of the high-frequency transformer.

11. The H-bridge micro inverter grid-connected device as claimed in claim 7, wherein the filter circuit comprises a resistor, capacitors and an inductor, the connection between the first thyristor and the second thyristor is connected with one terminal of the inductor, and the other terminal of the inductor is connected with one terminal of a first capacitor, one terminal of a second capacitor and a grid;

the other terminal of the second capacitor is connected with one terminal of the resistor, and the other terminal of the resistor is connected with the other terminal of the first capacitor and the grid.

12. The H-bridge micro inverter grid-connected device as claimed in claim 10, wherein each of the thyristors is provided with protection circuits comprising resistors and capacitors;

one terminal of a first resistor of the resistors and one terminal of a first capacitor of the capacitors are connected with the anode of the thyristor, and the other terminal of the first capacitor is connected with one terminal of a second resistor of the resistors;

the other terminal of the second resistor and one terminal of a second capacitor of the capacitors are connected with the cathode of the thyristor, the other terminal of the second capacitor is connected with a gate of the thyristor, and the other terminal of the first resistor and the gate of the thyristor are used as input terminals of voltage driving signals.