POWER CONVERSION DEVICE

• US 20130294124A1
• Filed: 07/11/2013
• Published: 11/07/2013
• Est. Priority Date: 04/10/2012
• Status: Active Grant

• Current Assignee: Fuji Electric Company Limited (Fuji Electric Systems Company Limited)
• Original Assignee: Fuji Electric Company Limited (Fuji Electric Systems Company Limited)
• Inventors: FUJITA, Satoru
• Granted Patent: US 9,571,001 B2
• Time in Patent Office: Days
• US Class Current: 363/84
• CPC Class Codes: H02M 7/04 by static converters
• CPC Class Codes: H02M 7/125 Avoiding or suppressing excessive transient voltages or currents
• CPC Class Codes: H02M 7/217 using semiconductor devices only
• CPC Class Codes: H02M 7/797 using semiconductor devices only

Abstract

Aspects of the invention include a step-up/step-down chopper unit, an inverter unit, a rectifier unit, first to third voltage detection means, and a drive control unit. Voltage regulation means of the drive control unit, in accordance with a detected voltage value detected by the voltage detection means, generates control signals for keeping the effective voltage value of a capacitor constant. In some aspects of the invention, the effective voltage value of the capacitor is controlled to be constant by the switching elements of the step-up/step-down chopper unit and inverter unit being driven by the control signals. The rectifier unit can suppress a surge voltage by causing energy stored in a inductor to be absorbed by storage elements when bidirectional switching elements are turned off.

Claims

1. A power conversion device, comprising:

a first series circuit wherein a first inductor and a first bidirectional switching element are connected in series;

a second series circuit, connected in parallel to the first bidirectional switching element, wherein a second bidirectional switching element and a capacitor are connected in series;

a serial switching element wherein 2N (N being a positive integer) switching elements, in each of which a diode is connected in anti-parallel, are connected in series;

a serial storage element, connected in parallel to the serial switching element, wherein first and second storage elements are connected in series;

a first serial rectifier element, connected in parallel to the serial storage element, wherein first and second rectifier elements are connected in series; and

a second inductor connected from an intermediate point of the 2N switching elements to a connection point of the second bidirectional switching element and capacitor, wherein

a connection point of the first and second storage elements is connected to a connection point of the first bidirectional switching element and the capacitor,

a connection point of the first and second rectifier elements is connected to a connection point of the first bidirectional switching element and second bidirectional switching element, and

alternating current applied to the first series circuit is converted, and output from both ends of the capacitor.

2. The power conversion device according to claim 1, further comprising:

a second serial rectifier element, connected in parallel to the first rectifier element, wherein third and fourth rectifier elements are connected in series, wherein

a connection point of the third and fourth rectifier elements is connected to a connection point of the second bidirectional switching element and capacitor.

3. The power conversion device according to claim 1, further comprising:

voltage detection means that detects the voltage value of the alternating current; and

a drive control unit that drives each of the first and second bidirectional switching elements and first and second switching elements,

the drive control unit including

a first mode that, when the alternating current voltage value detected by the voltage detection means is within a predetermined first voltage range, turns off the first bidirectional switching element, turns on the second bidirectional switching element, and drives the 2N switching elements to step-up the alternating current, thereby maintaining the voltage of the serial storage element at a predetermined voltage value,

a second mode that, when the alternating current voltage value is within a predetermined second voltage range lower than the first voltage range, drives the first and second bidirectional switching elements to step-up the alternating current and apply it to the capacitor, thereby maintaining the voltage of the capacitor at the predetermined voltage value, and drives the 2N switching elements to step-up the alternating current, thereby maintaining the voltage of the serial storage element at the predetermined voltage value,

a third mode that, when the alternating current voltage value is lower than the second voltage range, turns off the first and second bidirectional switching elements, and drives the 2N switching elements, thereby maintaining the voltage of the capacitor at the predetermined voltage value using power stored in the serial storage element, and

a fourth mode that, when the alternating current voltage value is higher than the first voltage range, turns off the first bidirectional switching element and drives the second bidirectional switching element to step-down the alternating current, thereby maintaining the voltage of the capacitor at the predetermined voltage value, and drives the 2N switching elements to step-up the alternating current, thereby maintaining the voltage of the serial storage element at the predetermined voltage value.

4. The power conversion device according to claim 3, wherein

the drive control unit includes a fifth mode that, when the alternating current voltage value is within a predetermined third voltage range lower than the second voltage range, and a time is within a predetermined time, turns off the second bidirectional switching element and drives the first bidirectional switching element to step-up the alternating current, thereby maintaining the voltage of the serial storage element at the predetermined voltage value, and drives the 2N switching elements, thereby maintaining the voltage of the capacitor at the predetermined voltage value using power stored in the serial storage element.

5. The power conversion device according to claim 3, wherein

the drive control unit includes a sixth mode that, when the alternating current voltage value is within a predetermined third voltage range lower than the second voltage range, a time is within a predetermined time, and the voltage phase of the alternating current is synchronous with the voltage phase of the capacitor, drives the first and second bidirectional switching elements to step-up the alternating current, and drives the 2N switching elements, thereby maintaining the voltage of the capacitor at the predetermined voltage value using power stored in the serial storage element.

6. The power conversion device according to claim 4, wherein

the drive control unit includes a sixth mode that, when the alternating current voltage value is within third voltage range, the time is within the predetermined time, and the voltage phase of the alternating current is synchronous with the voltage phase of the capacitor, drives the first and second bidirectional switching elements to step-up the alternating current, and drives the 2N switching elements, thereby maintaining the voltage of the capacitor at the predetermined voltage value using power stored in the serial storage element.

7. The power conversion device according to claim 1, further comprising:

a frequency detection means that detects the frequency of the alternating current,

the drive control unit including

a seventh mode that, when the alternating current voltage value is within, or higher than, the second voltage range and the frequency detection means detects that the voltage value is deviating from a predetermined frequency range, turns off the second bidirectional switching element and drives the first bidirectional switching element to step-up or step-down the alternating current, thereby maintaining the voltage of the serial storage element at the predetermined voltage value, and drives the 2N switching elements, thereby maintaining the voltage of the capacitor at the predetermined voltage value using power stored in the serial storage element.

8. The power conversion device according to claim 3, further comprising:

a frequency detection means that detects the frequency of the alternating current,

the drive control unit including

a seventh mode that, when the alternating current voltage value is within, or higher than, the second voltage range and the frequency detection means detects that the voltage value is deviating from a predetermined frequency range, turns off the second bidirectional switching element and drives the first bidirectional switching element to step-up or step-down the alternating current, thereby maintaining the voltage of the serial storage element at the predetermined voltage value, and drives the 2N switching elements, thereby maintaining the voltage of the capacitor at the predetermined voltage value using power stored in the serial storage element.

9. The power conversion device according to claim 4, further comprising:

a frequency detection means that detects the frequency of the alternating current,

the drive control unit including

a seventh mode that, when the alternating current voltage value is within, or higher than, the second voltage range and the frequency detection means detects that the voltage value is deviating from a predetermined frequency range, turns off the second bidirectional switching element and drives the first bidirectional switching element to step-up or step-down the alternating current, thereby maintaining the voltage of the serial storage element at the predetermined voltage value, and drives the 2N switching elements, thereby maintaining the voltage of the capacitor at the predetermined voltage value using power stored in the serial storage element.

10. The power conversion device according to claim 5, further comprising:

a frequency detection means that detects the frequency of the alternating current,

the drive control unit including

a seventh mode that, when the alternating current voltage value is within, or higher than, the second voltage range and the frequency detection means detects that the voltage value is deviating from a predetermined frequency range, turns off the second bidirectional switching element and drives the first bidirectional switching element to step-up or step-down the alternating current, thereby maintaining the voltage of the serial storage element at the predetermined voltage value, and drives the 2N switching elements, thereby maintaining the voltage of the capacitor at the predetermined voltage value using power stored in the serial storage element.

11. The power conversion device according to claim 6, further comprising:

a frequency detection means that detects the frequency of the alternating current,

the drive control unit including

a seventh mode that, when the alternating current voltage value is within, or higher than, the second voltage range and the frequency detection means detects that the voltage value is deviating from a predetermined frequency range, turns off the second bidirectional switching element and drives the first bidirectional switching element to step-up or step-down the alternating current, thereby maintaining the voltage of the serial storage element at the predetermined voltage value, and drives the 2N switching elements, thereby maintaining the voltage of the capacitor at the predetermined voltage value using power stored in the serial storage element.

12. The power conversion device according to claim 1, further comprising:

a third bidirectional switching element connected from a connection point of the 2N switching elements to a connection point of the first and second storage elements.

13. The power conversion device according to claim 12, further comprising:

a voltage detection means that detects the voltage value of the alternating current; and

a drive control unit that drives each of the first and second bidirectional switching elements and first and second switching elements,

the drive control unit including

a first mode that, when the alternating current voltage value detected by the voltage detection means is within a predetermined first voltage range, turns off the first bidirectional switching element, turns on the second bidirectional switching element, and drives so as to turn on any one of an upper arm side switching element or lower arm side switching element of the 2N switching elements or the third bidirectional switching element, stepping-up the alternating current and thereby maintaining the voltage of the serial storage element at a predetermined voltage value,

a second mode that, when the alternating current voltage value is within a predetermined second voltage range lower than the first voltage range, drives the first and second bidirectional switching elements to step-up the alternating current and apply it to the capacitor, thereby maintaining the voltage of the capacitor at the predetermined voltage value, and drives so as to turn on any one of the upper arm side switching element or lower arm side switching element of the 2N switching elements or the third bidirectional switching element, stepping-up the alternating current and thereby maintaining the voltage of the serial storage element at the predetermined voltage value,

a third mode that, when the alternating current voltage value is lower than the second voltage range, turns off the first and second bidirectional switching elements, and drives so as to turn on any one of the upper arm side switching element or lower arm side switching element of the 2N switching elements or the third bidirectional switching element, thereby maintaining the voltage of the capacitor at the predetermined voltage value using power stored in the serial storage element, and

a fourth mode that, when the alternating current voltage value is higher than the first voltage range, turns off the first bidirectional switching element and drives the second bidirectional switching element to step-down the alternating current, thereby maintaining the voltage of the capacitor at the predetermined voltage value, and drives so as to turn on any one of the upper arm side switching element or lower arm side switching element of the 2N switching elements or the third bidirectional switching element, stepping-up the alternating current and thereby maintaining the voltage of the serial storage element at the predetermined voltage value.

14. The power conversion device according to claim 13, wherein

the drive control unit includes a fifth mode that, when the alternating current voltage value is within a predetermined third voltage range lower than the second voltage range, and a time is within a predetermined time, turns off the second bidirectional switching element and drives the first bidirectional switching element to step-up the alternating current, thereby maintaining the voltage of the serial storage element at the predetermined voltage value, and drives so as to turn on any one of the upper arm side switching element or lower arm side switching element of the 2N switching elements or the third bidirectional switching element, thereby maintaining the voltage of the capacitor at the predetermined voltage value using power stored in the serial storage element.

15. The power conversion device according to claim 13, wherein

the drive control unit includes a sixth mode that, when the alternating current voltage value is within a predetermined third voltage range lower than the second voltage range, a time is within a predetermined time, and the voltage phase of the alternating current is synchronous with the voltage phase of the capacitor, drives the first and second bidirectional switching elements to step-up the alternating current within a range not exceeding the rated current value of each of the first bidirectional switching element and first inductor, and drives so as to turn on any one of the upper arm side switching element or lower arm side switching element of the 2N switching elements or the third bidirectional switching element, thereby maintaining the voltage of the capacitor at the predetermined voltage value using power stored in the serial storage element.

16. The power conversion device according to claim 14, wherein

the drive control unit includes a sixth mode that, when the alternating current voltage value is within third voltage range, a time is within a predetermined time, and the voltage phase of the alternating current is synchronous with the voltage phase of the capacitor, drives the first and second bidirectional switching elements to step-up the alternating current within a range not exceeding the rated current value of each of the first bidirectional switching element and first inductor, and drives so as to turn on any one of the upper arm side switching element or lower arm side switching element of the 2N switching elements or the third bidirectional switching element, thereby maintaining the voltage of the capacitor at the predetermined voltage value using power stored in the serial storage element.

17. The power conversion device according to claim 12, further comprising:

a frequency detection means that detects the frequency of the alternating current,

the drive control unit including

a seventh mode that, when the alternating current voltage value is within, or higher than, the second voltage range and the frequency detection means detects that the voltage value is deviating from a predetermined frequency range, turns off the second bidirectional switching element and drives the first bidirectional switching element to step-up or step-down the alternating current, thereby maintaining the voltage of the serial storage element at the predetermined voltage value, and drives so as to turn on any one of the upper arm side switching element or lower arm side switching element of the 2N switching elements or the third bidirectional switching element, thereby maintaining the voltage of the capacitor at the predetermined voltage value using power stored in the serial storage element.

18. The power conversion device according to claim 13, further comprising:

a frequency detection means that detects the frequency of the alternating current,

the drive control unit including

a seventh mode that, when the alternating current voltage value is within, or higher than, the second voltage range and the frequency detection means detects that the voltage value is deviating from a predetermined frequency range, turns off the second bidirectional switching element and drives the first bidirectional switching element to step-up or step-down the alternating current, thereby maintaining the voltage of the serial storage element at the predetermined voltage value, and drives so as to turn on any one of the upper arm side switching element or lower arm side switching element of the 2N switching elements or the third bidirectional switching element, thereby maintaining the voltage of the capacitor at the predetermined voltage value using power stored in the serial storage element.

19. The power conversion device according to claim 14, further comprising:

a frequency detection means that detects the frequency of the alternating current,

the drive control unit including

a seventh mode that, when the alternating current voltage value is within, or higher than, the second voltage range and the frequency detection means detects that the voltage value is deviating from a predetermined frequency range, turns off the second bidirectional switching element and drives the first bidirectional switching element to step-up or step-down the alternating current, thereby maintaining the voltage of the serial storage element at the predetermined voltage value, and drives so as to turn on any one of the upper arm side switching element or lower arm side switching element of the 2N switching elements or the third bidirectional switching element, thereby maintaining the voltage of the capacitor at the predetermined voltage value using power stored in the serial storage element.

20. The power conversion device according to claim 15, further comprising:

a frequency detection means that detects the frequency of the alternating current,

the drive control unit including

a seventh mode that, when the alternating current voltage value is within, or higher than, the second voltage range and the frequency detection means detects that the voltage value is deviating from a predetermined frequency range, turns off the second bidirectional switching element and drives the first bidirectional switching element to step-up or step-down the alternating current, thereby maintaining the voltage of the serial storage element at the predetermined voltage value, and drives so as to turn on any one of the upper arm side switching element or lower arm side switching element of the 2N switching elements or the third bidirectional switching element, thereby maintaining the voltage of the capacitor at the predetermined voltage value using power stored in the serial storage element.

21. The power conversion device according to claim 16, further comprising:

a frequency detection means that detects the frequency of the alternating current,

the drive control unit including

a seventh mode that, when the alternating current voltage value is within, or higher than, the second voltage range and the frequency detection means detects that the voltage value is deviating from a predetermined frequency range, turns off the second bidirectional switching element and drives the first bidirectional switching element to step-up or step-down the alternating current, thereby maintaining the voltage of the serial storage element at the predetermined voltage value, and drives so as to turn on any one of the upper arm side switching element or lower arm side switching element of the 2N switching elements or the third bidirectional switching element, thereby maintaining the voltage of the capacitor at the predetermined voltage value using power stored in the serial storage element.