Resonant converter

• US 20040052099A1
• Filed: 09/19/2003
• Published: 03/18/2004
• Est. Priority Date: 10/13/2000
• Status: Active Grant

• Current Assignee: American Power Conversion Denmark Aps (Schneider Electric SE)
• Original Assignee: American Power Conversion Denmark Aps (Schneider Electric SE)
• Inventors: Nielsen, Henning Roar
• Granted Patent: US 6,956,755 B2
• Time in Patent Office: Days
• US Class Current: 363/95
• CPC Class Codes: H02M 5/458 using semiconductor devices only
• CPC Class Codes: H02M 7/4815 Resonant converters H02M7/4811 and H02M7/4826 take precedence
• CPC Class Codes: H02M 7/538 in a push-pull configuration H02M7/5375 takes precedence ; with oscillating arrangements H02M7/53832, H02M7/53846
• 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: Y02P 80/10 Efficient use of energy, e.g. using compressed air or pressurized fluid as energy carrier

Abstract

The invention relates to a resonant converter (200, 300). The resonant converter (200, 300) consists of a furst circuit, primarily a DC circuit (201, 301) connected to a resonant circuit (207, 307) which is further connected to a switch/filter circuit (212, 312) which is connected to a second circuit, primarily an AC circuit (219, 319). The proposed resonant converter (200, 300) is unique in that the resonant converter (200, 300) contains a direct connection between a voltage centre (203, 303) in the DC circuit (201, 301) and a voltage centre (209, 309, 325) in the resonant circuit (207, 307), and that the resonant circuit (207, 307) contains at least one transformer having at least two windings (223, 224, 331, 332, 333, 334), wherein there is a connection from the windings (223, 224, 331, 332) of the transformer to at least first and second switches (215, 216, 315, 316, 328, 329), wherein activation of the switches (215, 216, 315, 316, 328, 329) forms a connection to at least a first node (214, 314, 327), wherein a voltage centre (203, 303) in the DC circuit (201, 301) is also connected to the first node (214, 314, 327) by activation of at least a third switch (213, 313, 326). This results in a resonant converter (200, 300) wherein there are just swiches (213, 215, 216, 313, 315, 316, 326, 328, 329) in the switch/filter circuit (212, 312) so that the number of switches (213, 215, 216, 313, 315, 316, 326, 328, 329) with power loss is as low as possible. The resonant converter (200, 300) moreover has the advantage that there is a direct connection from the centre (203, 303) of the DC circuit (201, 301) to the load (219, 319), without this current path running through the coil (217, 317, 330) to the resonant circuit (207, 307). This minimizes the current load of the coil (217, 317, 330) and hereby the influence on the frequency of the resonant converter in case of a short-circuit on the output of the resonant converter (200, 300) where a great output current is to be provided, while the output voltage is close to zero volt. The reason is that a switch (213, 313, 326) in the switch/filter circuit (212, 312), which is connected to a voltage centre (214, 314, 327), will conduct for by far the greatest part of the time at an output voltage close to zero volt, and that this current path bypasses the resonant circuit (207, 307). In addition, reduced switching across the switches (213, 215, 216, 313, 315, 316, 326, 328, 329) is achieved.

Claims

1. A resonant converter (200, 300) consisting of a first circuit, primarily a DC circuit (201, 301) connected to a resonant circuit (207, 307) which is further connected to a switch/filter circuit (212, 312), which is connected to a second circuit, primarily an AC circuit (219, 319), characterized in that the resonant converter (200, 300) contains a direct connection between a voltage centre (203, 303) in the DC circuit (201, 301) and a voltage centre (209, 309, 325) in the resonant circuit (207, 307), and that the resonant circuit (207, 307) contains at least one transformer having at least two windings (223, 224, 331, 332, 333, 334), wherein there is a connection from the windings (223, 224, 331, 332) of the transformer to at least first and second switches (215, 216, 315, 316, 328, 329), wherein activation of the switches (215, 216, 315, 316, 328, 329) forms a connection to at least a first node (214, 314, 327), wherein a voltage centre (203, 303) in the DC circuit (201, 301) is also connected to the first node (214, 314, 327) by activation of at least a third switch (213, 313, 326).

2. A resonant converter (300) according to claim 1, characterized in that the transformer has additional windings (332, 333) which operate in anti-phase to the windings (331, 334).

3. A resonant converter (200, 300) according to claim 1 or 2, characterized in that the resonant converter (200, 300) is used as a DC to AC converter.

4. A resonant converter (200, 300) according to claim 1 or 2, characterized in that the resonant converter (200, 300) is used as an AC to DC converter, wherein the first node (214, 314, 327) of the resonant converter (200, 300) is connected to an AC supply (219, 319), wherein the first node (214, 314, 327) is connected by activation of switches (215, 216, 315, 316, 328, 329) to windings (223, 224, 331, 332) on the transformer, said transformer having windings (223, 224, 331, 332) which are connected to a DC circuit (201, 301).

5. A resonant converter (200, 300) according to one of claims 1 to 4, characterized in that the resonant converter (200, 300) is incorporated in an N-phase system having at least one resonant converter (200, 300) per phase, the number of phases N being at least 1.

6. A resonant converter (200, 300) according to claim 5, characterized in that several switch/filter circuits in the N-phase system use the same common resonant circuit (207, 307) and the same common DC circuit (201, 301), wherein each phase is formed by activation of independent sets of switches (213, 215, 216, 313, 315, 316, 326, 328, 329).

7. A resonant converter (200, 300) according to one of claims 2, 5 or 6, characterized in that the resonant converter (200, 300) is used as an AC to AC converter.

8. A resonant converter (200, 300) according to claim 7, characterized in that the resonant converter (200, 300) is used for converting at least one of the parameters frequency, voltage and current.

9. A resonant converter (200, 300) according to one of claims 1 to 8, characterized in that semiconductors are used as switches comprising at least one of the types field effect transistor, bipolar transistor, Insulated Gate Bipolar Transistor (IGBT), Gate Turn-Off thyristor (GTO) and Injection Enhanced Gate Transistor (IEGT).

10. A resonant converter (200, 300) according to one of claims 1 to 9, characterized in that the resonant frequency (200, 300) uses three point modulation.

11. A resonant converter (200, 300) according to one of claims 1 to 10, characterized in that the resonance is controlled by the switches (213, 215, 216, 313, 315, 316, 326, 328, 329) in the switch/filter circuit (212, 312).

12. A resonant converter (200, 300) according to one of claims 1 to 10, characterized in that the resonance is controlled by a current source which is coupled magnetically to the resonant circuit (207, 307) via the core (208, 308).