Hybrid switch device

Abstract

A hybrid switching device includes a first switching element, a second switching element, and a controller. The first switching element can be controlled independently. The second switching element is connected in parallel with the first switching element and can also be controlled independently. The controller generates a control signal and controls the first and second switching elements separately according to the power operating points of the operating curves. Specifically, under light load conditions below the power operating point, the control signal controls the first switching element to turn on; under heavy load conditions above the power operating point, the control signal controls the second switching element to turn on, thereby optimizing the switching efficiency under hybrid operation of the first and second switching elements.

Claims

1. A hybrid switching device, comprising: A first switching element, which can be controlled independently; A second switching element is connected in parallel with the first switching element, and the second switching element can be controlled independently; A controller is provided to generate a control signal and control the first switching element and the second switching element respectively according to a power operating point of an operating curve. The forward characteristics of the first and second switching elements are as follows: below the power operating point, under the same forward voltage, the forward current of the first switching element is higher than that of the second switching element; above the power operating point, under the same forward voltage, the forward current of the first switching element is lower than that of the second switching element. Under a light load below the power operating point, the control signal controls the first switching element to conduct alone; under a heavy load above the power operating point, the control signal controls the second switching element to conduct alone. Under a light load below the power operating point, the second switching element remains completely off and does not perform switching; under a heavy load above the power operating point, the first switching element remains completely off and does not perform switching, thereby optimizing the switching efficiency under mixed operation of the first and second switching elements.

2. The hybrid switching device as claimed in claim 1, wherein under light load conditions below the power operating point, the control signal controls the second switching element to remain in a fully off state and not to perform switching; under heavy load conditions above the power operating point, the control signal controls the first switching element to remain in a fully off state and not to perform switching.

3. The hybrid switching device as claimed in claim 1, wherein under light load below the power operating point, the operating curve is a first forward characteristic curve of the first switching element; and under heavy load above the power operating point, the operating curve is a second forward characteristic curve of the second switching element.

4. The hybrid switching device as claimed in claim 1, wherein the first switching element is a metal oxide semiconductor field-effect transistor and the second switching element is an insulated gate bipolar transistor.

5. The hybrid switching device as claimed in claim 4, wherein the metal oxide semiconductor field-effect transistor system is a silicon carbide metal oxide semiconductor field-effect transistor, and the insulating gate bipolar transistor system is a silicon-based insulating gate bipolar transistor.

6. The hybrid switching device as claimed in claim 5, wherein the silicon carbide-based metal oxide semiconductor field-effect transistor comprises: The first switch; A first resistor is connected in series with the first switch to form a first series path; A second resistor; A first diode is connected in series with the second resistor to form a second series path; wherein the first series path is connected in parallel with the second series path.

7. The hybrid switching device as claimed in claim 5, wherein the silicon-based insulated gate bipolar transistor comprises: A second switch; A second diode is connected in series with the second switch; A third resistor, connected in series with the second diode to form a third series path; a fourth resistor; A third diode is connected in series with the fourth resistor to form a fourth series path; wherein the third series path is connected in parallel with the fourth series path.

8. The hybrid switching device as claimed in claim 1, wherein the number of the second switching elements is greater than the number of the first switching elements.

9. The hybrid switching device as claimed in claim 8, wherein the ratio of the number of the first switching elements to the number of the second switching elements is 1:

3.

10. The hybrid switching device as claimed in claim 8, wherein the ratio of the number of the first switching elements to the number of the second switching elements is 2:

2.

11. The hybrid switching device as claimed in claim 1, wherein the control signal includes a first control signal and a second control signal for controlling the first switching element and the second switching element, respectively.

12. The hybrid switching device as described in claim 5, wherein when the number of the silicon carbide metal oxide semiconductor field-effect transistor and the number of the silicon-based insulated-gate bipolar transistor are each one, the portion of the total current allocated to the silicon carbide metal oxide semiconductor field-effect transistor is I_total*I_SiC_ratio, and the portion of the total current allocated to the silicon-based insulated-gate bipolar transistor is I_total*(1-I_SiC_ratio); wherein, I_total represents the total current, and I_SiC_ratio represents the proportion of the total current allocated to the silicon carbide metal oxide semiconductor field-effect transistor.

13. The hybrid switching device as claimed in claim 12, wherein I_SiC_ratio is 1 when a forward voltage of the silicon carbide metal oxide semiconductor field-effect transistor is less than a starting voltage of the silicon-based insulated-gate bipolar transistor; I_SiC_ratio is less than 1 and greater than 0.5 when the forward voltage of the silicon carbide metal oxide semiconductor field-effect transistor is less than a forward voltage of the silicon-based insulated-gate bipolar transistor; I_SiC_ratio is 0.5 when the forward voltage of the silicon carbide metal oxide semiconductor field-effect transistor is equal to the forward voltage of the silicon-based insulated-gate bipolar transistor; and I_SiC_ratio is less than 0.5 and greater than 0 when the forward voltage of the silicon carbide metal oxide semiconductor field-effect transistor is greater than the forward voltage of the silicon-based insulated-gate bipolar transistor.

14. The hybrid switching device as claimed in claim 5, wherein the number of silicon carbide metal oxide semiconductor field-effect transistors is one, and the number of silicon-based insulated gate bipolar transistors is N, where N is a positive integer greater than 1, wherein the silicon carbide metal oxide semiconductor field-effect transistor is controlled to flow through a portion of the total current at an optimal power efficiency point, and the remaining N silicon-based insulated gate bipolar transistors all flow the remaining current.

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