BRIDGE CIRCUIT AND SHORT-CIRCUIT PROTECTION METHOD THEREOF

• US 20150256106A1
• Filed: 03/04/2015
• Published: 09/10/2015
• Est. Priority Date: 03/05/2014
• Status: Active Grant

• Current Assignee: Voltronic Power Technology Corp.
• Original Assignee: Voltronic Power Technology Corp.
• Inventors: HSIEH, JUOR-MING, YUAN, YI-SHENG, ZHAN, CHUN-JUAN
• Granted Patent: US 9,515,576 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02H 7/1213 for DC-DC converters
• CPC Class Codes: H02H 7/1222 responsive to abnormalities in the input circuit, e.g. transients in the DC input
• CPC Class Codes: H02M 1/0009 Devices or circuits for detecting current in a converter
• 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 1/32 Means for protecting converters other than automatic disconnection
• CPC Class Codes: H02M 7/5387 in a bridge configuration

Abstract

A bridge circuit and a short-circuit protection method thereof. The bridge circuit includes an input power unit, a converter unit, a first capacitor, a second capacitor, a detection unit and a bridge inverter unit. The input power unit includes a first electrode and a second electrode. The converter unit is coupled to the input power unit. The first capacitor includes a first terminal and a second terminal. The second capacitor includes a first terminal and a second terminal. The bridge inverter unit includes a plurality of switches and is coupled to the converter unit, the first capacitor, the second capacitor, the detection unit and the second electrode. The detection unit issues a short-circuit signal to a control unit when the detection unit detects a current variation on the second capacitor.

Claims

1. A bridge circuit, comprising:

an input power unit comprising a first electrode and a second electrode;

a converter unit being coupled to said input power unit;

a first capacitor comprising a first terminal and a second terminal, said first terminal of said first capacitor being coupled to said converter unit, said second terminal of said first capacitor being coupled to said second electrode;

a second capacitor comprising a first terminal and a second terminal, said first terminal of said second capacitor being coupled to said first terminal of said first capacitor;

a detection unit being coupled to said second terminal of said second capacitor; and

a bridge inverter unit comprising a plurality of switches and being coupled to said converter unit, said first capacitor, said second capacitor, said detection unit and said second electrode;

wherein said detection unit issues a short-circuit signal to a control unit when said detection unit detects a current variation on said second capacitor.

2. The bridge circuit of claim 1, wherein the capacitance of said first capacitor is larger than the capacitance of said second capacitor, said second capacitor being a high-frequency capacitor.

3. The bridge circuit of claim 1, wherein said detection unit comprises a first diode, an opto-coupler, a resistor and an operation voltage source, an anode of said first diode being coupled to said the second terminal of said second capacitor, a cathode of said first diode being coupled to said second electrode, said opto-coupler being coupled to said first diode, a grounding terminal and said resistor, said resistor being coupled to said operation voltage source.

4. The bridge circuit of claim 2, wherein said detection unit comprises a first diode, an opto-coupler, a resistor and an operation voltage source, an anode of said first diode being coupled to said the second terminal of said second capacitor, a cathode of said first diode being coupled to said second electrode, said opto-coupler being coupled to said first diode, a grounding terminal and said resistor, said resistor being coupled to said operation voltage source.

5. The bridge circuit of claim 3, wherein said current variation is a pre-determined current received by said opto-coupler to turn on said opto-coupler so that a low logic level is built between said resistor and said opto-coupler.

6. The bridge circuit of claim 4, wherein said current variation is a pre-determined current received by said opto-coupler to turn on said opto-coupler so that a low logic level is built between said resistor and said opto-coupler.

7. The bridge circuit of claim 5, wherein said opto-coupler comprises a first sensor unit and a second sensor unit, said first sensor unit being coupled to said first diode, said second sensor unit being coupled to said resistor and said grounding terminal.

8. The bridge circuit of claim 6, wherein said opto-coupler comprises a first sensor unit and a second sensor unit, said first sensor unit being coupled to said first diode, said second sensor unit being coupled to said resistor and said grounding terminal.

9. The bridge circuit of claim 7, wherein said first sensor unit is a light emitter and said second sensor unit is a photodetector, said pre-determined current flowing through said first sensor unit so that said first sensor unit issues an opto-coupler signal to said second sensor unit to turn on said second sensor unit so that said grounding terminal is electrically connected to said resistor, said short-circuit signal being a low logic level.

10. The bridge circuit of claim 8, wherein said first sensor unit is a light emitter and said second sensor unit is a photodetector, said pre-determined current flowing through said first sensor unit so that said first sensor unit issues an opto-coupler signal to said second sensor unit to turn on said second sensor unit so that said grounding terminal is electrically connected to said resistor, said short-circuit signal being a low logic level.

11. The bridge circuit of claim 1, wherein said converter unit is a boost circuit, a buck circuit or a buck-boost circuit.

12. The bridge circuit of claim 2, wherein said converter unit is a boost circuit, a buck circuit or a buck-boost circuit.

13. The bridge circuit of claim 1, wherein said converter unit comprises an inductor element, a diode element and a switch element, said inductor element being coupled to said first electrode of said input power unit and an anode of said diode element, a cathode of said diode element being coupled to said inductor element, said first capacitor, said second capacitor and said bridge inverter unit.

14. The bridge circuit of claim 2, wherein said converter unit comprises an inductor element, a diode element and a switch element, said inductor element being coupled to said first electrode of said input power unit and an anode of said diode element, a cathode of said diode element being coupled to said inductor element, said first capacitor, said second capacitor and said bridge inverter unit.

15. The bridge circuit of claim 1, wherein said bridge inverter unit is a single-phase bridge inverter or a three-phase bridge inverter, wherein said bridge inverter unit turns an output of said input power unit into an alternate-current (AC) voltage to be supplied to a load.

16. The bridge circuit of claim 2, wherein said bridge inverter unit is a single-phase bridge inverter or a three-phase bridge inverter, wherein said bridge inverter unit turns an output of said input power unit into an alternate-current (AC) voltage to be supplied to a load.

17. A short-circuit protection method of a bridge circuit, said bridge circuit comprising an input power unit, a converter unit, a first capacitor, a second capacitor, a detection unit and a bridge inverter unit, said input power unit being coupled to said converter unit, said first capacitor being coupled to said converter unit, said second capacitor and said first capacitor being connected in parallel, said second capacitor and said detection unit being connected in series, said bridge inverter unit being coupled to said second capacitor and said detection unit, and said short-circuit protection method comprising steps of:

determining by said detection unit whether a current variation on said second capacitor has been detected; and

issuing by said detection unit a short-circuit signal to a control unit so that said control unit controls said bridge inverter unit to stop if said current variation on said second capacitor has been detected.

18. The short-circuit protection method of claim 17, wherein said step of determining whether said current variation on said second capacitor has been detected further comprises steps of:

determining by an opto-coupler of said detection unit whether a pre-determined current has been received; and

turning on said opto-coupler so that a resistor coupled to said opto-coupler issues said short-circuit signal if said pre-determined current has been received.