DC-DC CONVERTER, SECONDARY BATTERY CHARGE AND DISCHARGE SYSTEM, AND METHOD OF CONTROLLING DC-DC CONVERTER

• US 20150214847A1
• Filed: 01/23/2015
• Published: 07/30/2015
• Est. Priority Date: 01/24/2014
• Status: Active Grant

• Current Assignee: Hitachi Information & Telecommunication Engineering, Ltd. (Hitachi, Ltd.)
• Original Assignee: Hitachi Information & Telecommunication Engineering, Ltd. (Hitachi, Ltd.)
• Inventors: SHIMADA, Takae, TANIGUCHI, Kimiaki, SHOJI, Hiroyuki, WATANABE, Kuniyoshi
• Granted Patent: US 9,595,841 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/342 The other DC source being a battery actively interacting with the first one, i.e. battery to battery charging with circuits for polarity protection H02J7/0034
• CPC Class Codes: H02M 1/0058 by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero using an auxiliary actively switched resonant commutation circuit connected to an intermediate DC voltage or between two push-pull branches of an inverter bridge H02M7/4811; in resonant inverters H02M7/4815; in inverters operating from a resonant DC source H02M7/4826
• CPC Class Codes: H02M 1/32 Means for protecting converters other than automatic disconnection
• CPC Class Codes: H02M 1/322 Means for rapidly discharging a capacitor of the converter for protecting electrical components or for preventing electrical shock
• CPC Class Codes: H02M 3/01 Resonant DC/DC converters
• CPC Class Codes: H02M 3/33573 Full-bridge at primary side of an isolation transformer
• CPC Class Codes: H02M 3/33584 Bidirectional converters
• 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

Abstract

In a DC-DC converter, a smoothing capacitor is connected between DC terminals of the switching circuit, and a smoothing capacitor and a voltage clamp circuit are connected between DC terminals of a switching circuit, the voltage clamp circuit including the switching device and the clamp capacitor. The smoothing capacitors are connected to the DC power sources) in parallel, respectively. The winding of the switching circuit is magnetically coupled to the winding of the switching circuit by the transformer. The DC-DC converter performs a discharging operation for discharging the clamp capacitor between at least one of the step-down operation and a step-up operation and a step-up operation performed thereafter.

Claims

1. A DC-DC converter comprising:

a first switching circuit in which a first smoothing capacitor is connected between DC terminals, and a primary winding is connected between AC terminals;

a second switching circuit in which a smoothing inductor and a second smoothing capacitor which are connected in series and connected between DC terminals, and a secondary winging is connected to AC terminals;

a transformer providing magnetic coupling between the primary winding to the secondary winding;

a voltage clamp circuit, including a clamp capacitor and a clamp switching device which are connected in series, the voltage clamp circuit being connected between DC terminals of the second switching circuit or between the AC terminals of the second switching circuit and one end of the second smoothing capacitor;

a controller operating either of a first mode or a second operation mode, wherein in the first mode, a power inputted between the first terminals, which are both terminals of the first smoothing capacitor, is outputted between the second terminals, which are both terminals of the second smoothing capacitor, and in the second mode a power inputted between the second terminals is outputted between the first terminals, wherein

in a third mode, the controller outputs, between the first terminals and/or the second terminals, a power discharged from the clam p capacitor by switching the clamp switching device, the third mode being performed between an interruption after the first mode or after the second mode and the second mode performed subsequent to the interruptions.

2. The DC-DC converter as claimed in claim 1, wherein in the third operation mode, when all of the switching devices included in the second switching circuit are turned off, the controller controls the clamp switching device to turn off.

3. The DC-DC converter as claimed in claim 1, wherein

the second switching circuit includes

a first switching leg including a first switching device and a second switching device connected in series, wherein

a second switching leg connected to the first switching leg in parallel, the second switching leg including a third switching device and a fourth switching device connected in series, wherein

both ends of the first switching leg are the DC terminals, and wherein

a series junction between the first switching device and the second switching device and a series junction between the third switching device and the fourth switching device are the AC terminals.

4. The DC-DC converter as claimed in claim 3, wherein

the voltage clamp circuit is connected between the DC terminals of the second switching circuit, and wherein

the second operation mode includes an operation of fixing the clamp switching device is in an ON state and switching the first to fourth switching device.

5. The DC-DC converter as claimed in claim 1, wherein

the secondary winding includes first and second secondary windings and a connecting member connecting one of the first secondary winding to one end of the second secondary winding,

the second switching circuit includes a first switching device and a second switching device, wherein

another end of the first secondary winding is connected to one end of the first switching device of the second switching circuit, wherein

another end of the second secondary winding is connected to one end of the second switching device, wherein

another end of the first switching device is connected to another end of the second switching device, wherein

a junction between the first switching device and the second switching device and a junction between the first secondary winding and the second secondary winding are the DC terminals of the second switching circuit, and wherein

the one end of the first switching device and the the one end of the second switching device are AC terminals.

6. The DC-DC converter as claimed in claim 1, wherein

the smoothing inductor includes a connecting member connecting the one end of the first smoothing inductor to the one end of the second smoothing inductor, wherein

the second switching circuit includes a connecting member connecting the one end of the first switching device and the one end of the second switching device, wherein

another end of the first switching device is connected to another end of the first smoothing inductor, wherein

another end of the second switching device is connected to another end of the second smoothing inductor, wherein

the second smoothing capacitor is connected between a junction between the first smoothing inductor and the second smoothing inductor and a junction between the first switching device and the second switching device, wherein

both ends of the first switching device and both ends of the second switching device are the DC terminals of the second switching circuit, and wherein

another end of the first switching device and another end of the second switching device are the AC terminals of the second switching circuit.

7. The DC-DC converter as claimed in claim 1, wherein

the third operation mode include an operation switching the clamp switching device at a switching frequency lower than a switching frequency of the clamp switching device in the first and second operation mode.

8. The DC-DC converter as claimed in claim 1, wherein

the first switching circuit includes:

a third switching leg including a fifth switching device and a sixth switching device connected in series, and

a fourth switching leg connected to the third switching leg in parallel, the fourth switching leg including a seventh switching device and an eighth switching device connected in series, wherein

both ends of the third switching leg are DC terminals, and wherein

a series junction of the fifth switching device and the sixth switching device and the series junction between the seventh switching device and the eighth switching device are AC terminals,

9. The DC-DC converter as claimed in claim 1, wherein

a power is transmitted and received between the first DC power source connected to the first terminals and a second DC power source connected to the second terminals.

10. The DC-DC converter as claimed in claim 1, further comprising

a resonating capacitor and/or a resonating inductor connected to the primary winding and/or secondary winding.

11. The DC-DC converter as claimed in claim 1, further comprising diodes connected to respective switching devices in anti-parallel connection, respectively.

12. A secondary battery charge and discharge system comprising:

the DC-DC converter as claimed in claim 1.

13. A method of controlling a DC-DC converter including:

a first switching circuit in which a first smoothing capacitor is connected between DC terminals, and a primary winding is connected between AC terminals;

a second switching circuit in which a smoothing inductor and a second smoothing capacitor which are connected in series and connected between DC terminals, and a secondary winging is connected to AC terminals;

a transformer providing magnetic coupling between the primary winding to the secondary winding;

a voltage clamp circuit, including a clamp capacitor and a clamp switching device which are connected in series, the voltage clamp circuit being connected between DC terminals of the second switching circuit or between the AC terminals of the second switching circuit and one end of the second smoothing capacitor;

a controller controlling the first and second switching circuits, the method comprising;

a step providing interruption after control in either of a first operation mode to output a power inputted to the first terminals, which are both ends of the first smoothing capacitor at second terminals, which are both ends of the second smoothing capacitor or a second operation mode to output a power inputted between the second terminals at the first terminals,

a step provides control in a third operation mode to output a power discharged from the clamp capacitor by switching the clamp switching device at least one of the first terminals and the second terminals, and

a step starting control in the second operation mode after the third operation mode.