Slave circuit for distributed power converters in a solar module

• US 9,356,537 B2
• Filed: 12/31/2012
• Issued: 05/31/2016
• Est. Priority Date: 10/25/2012
• Status: Active Grant

• Current Assignee: mPowerSolar Inc
• Original Assignee: SunEdison Microinverter Products LLC
• Inventors: Potharaju, Suryanarayana, Jayaraman, Vijay Shankar
• Primary Examiner(s): Zhang, Jue
• Assistant Examiner(s): ROSARIO BENITEZ, GUSTAVO A
• Application Number:
  US13/732,154
• Publication Number:
  US 20140119085A1
• Time in Patent Office: 1,247 Days
• US Class Current: 1/1
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 2300/26 involving maximum power point tracking control for photovoltaic sources
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 3/388 Islanding, i.e. disconnection of local power supply from the network
• CPC Class Codes: H02J 3/46 Controlling of the sharing of output between the generators, converters, or transformers
• CPC Class Codes: H02M 1/0051 Diode reverse recovery losses
• 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 1/34 Snubber circuits
• CPC Class Codes: H02M 1/346 Passive non-dissipative snubbers
• CPC Class Codes: H02M 7/5387 in a bridge configuration
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers

Abstract

An inverter device for a solar module. The inverter device comprises a slave circuit device that includes an input comprising a DC input from a solar cell group and a preliminary boost circuit. A DC boost circuit is coupled to the preliminary boost circuit and configured to boost the intermediary voltage to an AC RMS peak voltage. A rectifier circuit is coupled to the DC boost circuit. An energy recovery circuit comprises a storage device coupled to the rectifier output. The energy recovery circuit is configured to temporarily store a reverse recovery charge and transfers the reverse recovery charge to an output of a DC bus structure to reduce a diode recovery loss in the rectifier circuit.

Claims

1. An inverter device for a solar module, the inverter device comprising a slave circuit device comprising:

an input comprising a DC input from a solar cell group;

a preliminary boost circuit coupled to the input, the preliminary boost circuit configured to boost an input voltage from the input from the solar cell group to an intermediary voltage;

a boost circuit coupled to the preliminary boost circuit and configured to boost the intermediary voltage to a boosted output having an AC RMS peak voltage;

a rectifier circuit coupled to the boost circuit and configured to wave shape the boosted output to a rectified DC waveform, the rectifier circuit comprising an rectifier output;

an energy recovery circuit comprises a storage device coupled to the rectifier output, the energy recovery circuit being configured to temporarily store a reverse recovery charge and transfers the reverse recovery charge to an output of a DC bus structure to reduce a diode recovery loss in the rectifier circuit,

wherein the rectifier circuit comprises a full bridge diode circuit coupled with the energy recovery circuit;

wherein the storage device comprises a storage capacitor coupled to the rectifier output, the storage capacitor being configured between a first terminal and a second terminal of the full bridge diode circuit, the energy recovery circuit further comprising a first p-n junction diode configured in series with the storage capacitor, the energy recovery circuit further comprising an inductor coupled to the first terminal and the first p-n junction diode, the inductor being in parallel to the storage capacitor.

2. The device of claim 1 wherein the input comprises a first terminal and a second terminal;

wherein the DC input ranges from about 4 volts to 120 volts.

3. The device of claim 1 wherein the preliminary boost circuit comprises an inductive storage coupled to a capacitive storage coupled within a boost circuit.

4. The device of claim 1 wherein the boost circuit comprises a phase shift full bridge boost circuit or an advanced boost circuit achieving Zero-Voltage-Switching (ZVS) or Zero-Current-Switching (ZCS) or both ZVS and ZCS.

5. The device of claim 1 wherein the energy recovery circuit further comprising a second p-n junction diode provided between the first p-n junction diode and the storage capacitor, the second p-n junction diode being coupled to an output terminal of the DC bus structure.

6. The device of claim 5 wherein the second p-n junction diode is configured to allow a switching current to flow to the output terminal;

and the first p-n junction diode is configured to allow to a node between the second p-n junction diode and the storage capacitor to be substantially at an output terminal voltage at the DC bus structure.

7. The device of claim 1 wherein the intermediary voltage ranges from about 15 volts to 20 volts.

8. The device of claim 1 wherein the rectified DC waveform has a voltage ranging from about 160 volts to 400 volts.

9. The device of claim 1 wherein the solar cell group is provided in a solar module.

10. The device of claim 1 wherein the slave circuit provides a galvanic isolation between the DC input from the solar cell group and a combined AC supply which is either from a grid source or a reference AC signal generated by another device.

11. The device of claim 1 wherein the storage capacitor is metal or ceramic filled capacitor structure having a capacitance determined by a frequency of switching on the rectifier circuit, the reverse recovery charge, and a voltage across the rectifier output.

12. A method of operating an inverter device for a solar module, the method comprising:

receiving an input voltage at a DC input from a solar cell group;

receiving the DC input and increasing the input voltage from the input to an intermediary voltage using a preliminary boost circuit;

receiving the intermediary voltage at a boost circuit coupled to the preliminary boost circuit, and outputting a boosted output having an AC RMS peak voltage;

receiving the boosted output at a rectifier circuit coupled to the boost circuit, and wave shaping the boosted output to a rectified DC waveform at a rectifier output;

receiving the rectified DC waveform at an energy recovery circuit;

storing a reverse recovery charge at a storage device configured with the energy recovery circuit; and

transferring the reverse recovery charge from the storage device to an output of a DC bus structure to reduce a diode recovery loss in the rectifier circuit,

wherein the rectifier circuits comprises a full bridge diode circuit coupled with the energy recovery circuit;

wherein the storage device comprises a storage capacitor coupled to the rectifier output, the storage capacitor being configured between a first terminal and a second terminal of the full bridge diode circuit, the energy recovery circuit further comprising a first p-n junction diode configured in series with the storage capacitor, the energy recovery circuit further comprising an inductor coupled to the first terminal and the first p-n junction diode, the inductor being in parallel to the storage capacitor;

wherein the energy recovery circuit further comprising a second p-n junction diode provided between the first p-n junction diode and the storage capacitor, the second p-n junction diode being coupled to an output terminal of the DC bus structure;

wherein the second p-n junction diode is configured to allow a switching current to flow to the output terminal; and

the first p-n junction diode is configured to allow a node between the second p-n junction diode and the storage capacitor to be substantially at an output terminal voltage at the DC bus structure.

13. The method of claim 12 wherein the input comprises a first terminal and a second terminal;

wherein the DC input ranges from about 4 volts to 120 volts;

wherein the preliminary boost circuit comprises an inductive storage coupled to a capacitive storage coupled within a boost circuit.

14. The method of claim 12 wherein the boost circuit comprises a phase shift full bridge boost circuit or an advanced boost circuit achieving Zero-Voltage-Switching (ZVS) or Zero-Current-Switching (ZCS) or both ZVS and ZCS.

15. The method of claim 12 wherein the intermediary voltage ranges from about 15 volts to 20 volts;

wherein the rectified DC waveform has a voltage ranging from about 160 volts to 400 volts.

16. The method of claim 12 wherein the solar cell group is provided in a solar module;

wherein the slave circuit provides a galvanic isolation between the DC input from the solar cell group and a combined AC supply which is either from a grid source or a reference AC signal generated by another device;

wherein the storage capacitor is metal or ceramic filled capacitor structure having a capacitance determined by a frequency of switching on the rectifier circuit, the reverse recovery charge, and a voltage across the rectifier output.