BIDIRECTIONAL ACTIVE POWER CONDITIONER

• US 20080062724A1
• Filed: 06/11/2007
• Published: 03/13/2008
• Est. Priority Date: 09/12/2006
• Status: Active Grant

• Current Assignee: Ablerex Electronics Company Limited (Ablerex Overseas Corporation Limited)
• Original Assignee: Ablerex Electronics Company Limited (Ablerex Overseas Corporation Limited)
• Inventors: WU, Chin-Chang, FENG, Ya-Tsung, CHOU, Hung-Liang
• Granted Patent: US 7,733,670 B2
• Time in Patent Office: Days
• US Class Current: 363/17
• CPC Class Codes: H02J 7/35 with light sensitive cells
• CPC Class Codes: H02J 9/062 for AC powered loads
• 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 3/33584 Bidirectional converters
• CPC Class Codes: H02M 3/33592 having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer
• CPC Class Codes: H02M 3/3378 in a push-pull configuration of the parallel type H02M3/3374 takes precedence
• CPC Class Codes: Y02B 10/70 Hybrid systems, e.g. uninterruptible or back-up power supplies integrating renewable energies
• 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

A bidirectional active power conditioner includes a DC side, a bidirectional DC/DC power converter, a DC/AC inverter and an AC side. The DC side electrically connects with a DC source while the AC side electrically connects with a load and an AC source. The bidirectional DC/DC power converter is controlled via high-frequency pulse width modulation (PWM) switching so as to generate a predetermined DC voltage or DC current while the DC/AC inverter is controlled to convert the predetermined DC voltage or DC current into a predetermined AC voltage or AC current.

Claims

1. A bidirectional active power conditioner, comprising:

a DC side connected to a DC source;

a bidirectional DC/DC power converter connected to the DC side, said bidirectional DC/DC power converter being controlled via high-frequency PWM switching so as to generate a predetermined DC voltage or a predetermined DC current;

a DC/AC inverter connected with the bidirectional DC/DC power converter, said DC/AC inverter converting the predetermined DC voltage or the predetermined DC current generated from the bidirectional DC/DC power converter into a predetermined AC voltage or a predetermined AC current; and

an AC side connected with the DC/AC inverter, said AC side further connected with one or both of a load and an AC source.

2. The bidirectional active power conditioner as defined in claim 1, wherein the DC source is selected from a battery unit.

3. The bidirectional active power conditioner as defined in claim 1, wherein the DC source is selected from a solar cell unit and an energy storage system which are connected in parallel.

4. The bidirectional active power conditioner as defined in claim 3, wherein the energy storage system includes a battery unit and a battery charger.

5. The bidirectional active power conditioner as defined in claim 1, wherein the bidirectional DC/DC power converter includes a plurality of power electronic switches, a high-frequency isolation transformer and an inductor, said bidirectional DC/DC power converter having a primary side and a secondary side.

6. The bidirectional active power conditioner as defined in claim 5, wherein the power electronic switch of the bidirectional DC/DC power converter includes a power switch element and a diode which are connected in anti-parallel relationship.

7. The bidirectional active power conditioner as defined in claim 5, wherein two of the power electronic switches located at the secondary side of the high-frequency isolation transformer to configure a push-pull structure which is further connected with the DC/AC inverter of the bidirectional active power conditioner via the inductor.

8. The bidirectional active power conditioner as defined in claim 5, wherein two of the power electronic switches located at the primary side of the high-frequency isolation transformer to configure a push-pull structure which is further connected with the DC side.

9. The bidirectional active power conditioner as defined in claim 5, wherein two of the power electronic switches and two equivalent capacitors are located at the primary side of the high-frequency isolation transformer to configure a half-bridge structure which is further connected to the DC side.

10. The bidirectional active power conditioner as defined in claim 5, wherein four of the power electronic switches are located at the primary side of the high-frequency isolation transformer to configure a full-bridge structure which is further connected to the DC side.

11. The bidirectional active power conditioner as defined in claim 5, wherein during transmitting power from the secondary side to the primary side of the high-frequency isolation transformer, the power electronic switches located at the primary side are completely disabled, and the power electronic switches located at the secondary side are controlled via high-frequency PWM switching.

12. The bidirectional active power conditioner as defined in claim 5, wherein, in a bidirectional power flow, all of the power electronic switches are controlled via high-frequency PWM switching, and in a switching operation the power electronic switch located at the primary side and the power electronic switch located at the secondary side are complementary.

13. The bidirectional active power conditioner as defined in claim 1, wherein the DC/AC inverter includes four power electronic switches and a filter capacitor.

14. The bidirectional active power conditioner as defined in claim 13, wherein the power electronic switch of the DC/AC inverter includes a power switch element and a diode which are connected anti-parallel relationship.

15. The bidirectional active power conditioner as defined in claim 13, wherein the electronic switches of the DC/AC inverter configure a full bridge structure.

16. The bidirectional active power conditioner as defined in claim 13, wherein during transmitting power from the AC side to the DC side of the bidirectional active power conditioner, the power electronic switches of the DC/AC inverter are completely disabled so that four diodes provided in the four power electronic switches are actuated the DC/AC inverter as a rectifier.

17. The bidirectional active power conditioner as defined in claim 13, wherein, in a bidirectional power flow, the power electronic switches of the DC/AC inverter are controlled in a low-frequency square-wave switching.

18. The bidirectional active power conditioner as defined in claim 1, wherein the AC source electrically connects with the AC side via a switch for supplying power to the load;

the AC source being used to charge the DC source via the bidirectional active power conditioner, power electronic switches of the bidirectional DC/DC power converter being controlled to generate a current passing through the inductor to have a full-wave rectified sinusoidal waveform, the DC/AC inverter commutating the full-wave rectified sinusoidal current to be a sinusoidal current inputted from the AC side such that a phase of the inputted current is approximately equal to that of the voltage supplied from the AC power source so as to obtain an unity power factor in the AC side of the bidirectional active power conditioner.

19. The bidirectional active power conditioner as defined in claim 1, wherein the AC source electrically connects with the AC side via a switch for supplying power to the load and supplying the power to the DC source via the bidirectional active power conditioner, the bidirectional active power conditioner being further functioned as an active power filter, controlling power electronic switches of the bidirectional DC/DC power converter to generate a full-wave rectified waveform of a compensation current, the DC/AC inverter commutating the full-wave rectified waveform of a compensation current to generate an AC compensation current which is injected into the AC source so that a current supplied from the AC source is sinusoidal and in phase with the voltage of AC source so as to obtain an unity power factor from the AC source.

20. The bidirectional active power conditioner as defined in claim 1, wherein when the AC side is only connected to the load or the AC source connected to the AC side is abnormal or fails, power electronic switches of the bidirectional DC/DC power converter are controlled to generate a full-wave rectified sinusoidal waveform of voltage and the DC/AC inverter commutates the full-wave rectified sinusoidal waveform of voltage into a sinusoidal waveform of AC voltage to supply to the load.