Quasiresonant boost power converter with bidirectional inductor current

Claim 2

A boost power converter for powering a load with an AC power source, comprising: (a) an energy storage device; (b) a resonant circuit; (c) a resonator switch circuit adapted to alternately connect the resonant circuit to different sides of the energy storage device, wherein power from the energy storage device is transferred by the resonant circuit to the load; (d) a boost inductor circuit; and (e) a boost switch circuit electrically coupled between the boost inductor circuit and the resonator switch circuit and adapted to selectively connect the boost inductor circuit to the resonator switch circuit, such that a boost inductor of the boost inductor circuit is charged in one of two different directions depending on the phase of the AC power source.

Claim 3

The invention of claim 1, wherein the load comprises a fluorescent lamp.

Claim 4

The invention of claim 1, wherein the resonator switch circuit is configured for substantially fully resonant, zero-voltage switching.

Claim 5

The invention of claim 1, wherein: the resonant circuit comprises a resonant inductor and a resonant capacitor; the resonator switch circuit comprises a first switching device and a second switching device, each electrically coupled to the resonant circuit and configured for zero-voltage switching; the energy storage device comprises a capacitor electrically coupled to the first and second switching devices; the boost inductor is electrically coupled to the AC power source; the boost switch circuit comprises a third switching device electrically coupled between the boost inductor and the first and second switching devices; and the boost power converter operates in either a first operating mode or a second operating mode, depending on the phase of the AC power source.

Claim 6

The invention of claim 4, wherein: in the first operating mode, the third switching device is configured to remain closed when the first switching device opens and when the second switching device closes; and in the second operating mode, the third switching device is configured to remain closed when the second switching device opens and when the first switching device closes.

Claim 7

The invention of claim 5, wherein: in the first operating mode, the third switching device is configured to close at substantially the same time that the first switching device closes; and in the second operating mode, the third switching device is configured to close at substantially the same time that the second switching device closes.

Claim 8

The invention of claim 4, wherein the boost switch circuit further comprises a power-factor correction controller configured to control the third switching device to cause a bidirectional current through the boost inductor in phase with a voltage of the AC power source.

Claim 9

The invention of claim 7, wherein: in the first operating mode, the power-factor correction controller is configured to open the third switching device in response to a voltage of the AC power source, while the first switching device is open and the second switching device is closed, in order to discharge the boost inductor and provide a high power factor; and in the second operating mode, the power-factor correction controller is configured to open the third switching device in response to a voltage of the AC power source, while the second switching device is open and the first switching device is closed, in order to discharge the boost inductor and provide a high power factor.

Claim 10

The invention of claim 4, wherein the first and second switching devices are configured to zero-voltage switch the resonant circuit between the different sides of the energy storage device.

Claim 11

The invention of claim 4, wherein the first, second, and third switching devices are configured to zero-voltage switch the boost inductor between the different sides of the energy storage device.

Claim 12

The invention of claim 4, wherein the first, second, and third switching devices and the resonant circuit are each electrically coupled to a common node.

Claim 13

The invention of claim 4, wherein the first and second switching devices are configured for switching at approximately a 50% duty cycle.

Claim 14

The invention of claim 4, wherein the energy storage device is configured to provide a higher voltage than a peak of the AC power source.

Claim 17

The method of claim 14, wherein: step (b) comprises the step of coupling the boost inductor to the resonator switch circuit to begin charging the inductor; step (c) comprises the step of decoupling the boost inductor from the resonant circuit to discharge the inductor into the energy storage device; and step (d) comprises the step of zero-voltage switching.

Claim 18

The method of claim 14, wherein the load comprises a fluorescent lamp.

Claim 19

A boost power converter for powering a load with an AC power source, comprising: (a) an energy storage device; (b) a resonant circuit; (c) a resonator switch circuit adapted to alternately connect the resonant circuit to different sides of the energy storage device, wherein power from the energy storage device is transferred by the resonant circuit to the load; (d) a boost inductor circuit; and (e) a boost switch circuit adapted to selectively connect the boost inductor circuit to the resonator switch circuit, such that a boost inductor of the boost inductor circuit is charged in one of two different directions depending on the phase of the AC power source, wherein: the resonant circuit comprises a resonant inductor and a resonant capacitor; the resonator switch circuit comprises a first switching device and a second switching device, each electrically coupled to the resonant circuit and configured for zero-voltage switching; the energy storage device comprises a capacitor electrically coupled to the first and second switching devices; the boost inductor is electrically coupled to the AC power source; the boost switch circuit comprises a third switching device electrically coupled between the boost inductor and the first and second switching devices; and the boost power converter operates in either a first operating mode or a second operating mode, depending on the phase of the AC power source.

Claim 20

A boost power converter for powering a load with an AC power source, comprising: (a) an energy storage device; (b) a resonant circuit; (c) a resonator switch circuit adapted to alternately connect the resonant circuit to different sides of the energy storage device, wherein power from the energy storage device is transferred by the resonant circuit to the load; (d) a boost inductor circuit; and (e) a boost switch circuit adapted to selectively connect the boost inductor circuit to the resonator switch circuit, such that a boost inductor of the boost inductor circuit is charged in one of two different directions depending on the phase of the AC power source, wherein: the resonant circuit comprises a resonant inductor and a resonant capacitor; the resonator switch circuit comprises a first switching device and a second switching device, each electrically coupled to the resonant circuit and configured for zero-voltage switching; the energy storage device comprises a capacitor electrically coupled to the first and second switching devices; the boost inductor is electrically coupled to the AC power source; the boost switch circuit comprises a third switching device electrically coupled between the boost inductor and the first and second switching devices; and the boost power converter operates in either a first operating mode or a second operating mode, depending on the phase of the AC power source.

Claim 21

The invention of claim 17, wherein: in the first operating mode, the third switching device is configured to remain closed when the first switching device opens and when the second switching device closes; in the second operating mode, the third switching device is configured to remain closed when the second switching device opens and when the first switching device closes; in the first operating mode, the third switching device is configured to close at substantially the same time that the first switching device closes; and in the second operating mode, the third switching device is configured to close at substantially the same time that the second switching device closes.

Claim 22

The invention of claim 17, wherein the boost switch circuit further comprises a power-factor correction controller configured to control the third switching device to cause a bidirectional current through the boost inductor in phase with a voltage of the AC power source, wherein: in the first operating mode, the power-factor correction controller is configured to open the third switching device in response to a voltage of the AC power source, while the first switching device is open and the second switching device is closed, in order to discharge the boost inductor and provide a high power factor; and in the second operating mode, the power-factor correction controller is configured to open the third switching device in response to a voltage of the AC power source, while the second switching device is open and the first switching device is closed, in order to discharge the boost inductor and provide a high power factor.

Claim 23

The invention of claim 17, wherein: the first and second switching devices are configured to zero-voltage switch the resonant circuit between the different sides of the energy storage device; the first, second, and third switching devices are configured to zero-voltage switch the boost inductor between the different sides of the energy storage device; the first, second, and third switching devices and the resonant circuit are each electrically coupled to a common node; the first and second switching devices are configured for switching at approximately a 50% duty cycle; and the energy storage device is configured to provide a higher voltage than a peak of the AC power source.