Power converter with current feedback loop

Patent metadata

Field	Value
Publication number	US-9343986-B2
Application number	US-201414156851-A
Country	US
Kind code	B2
Filing date	Jan 16, 2014
Priority date	Jan 16, 2013
Publication date	May 17, 2016
Grant date	May 17, 2016

Abstract

In a power converter, a driver drives a switching element using a manipulated variable therefor to convert input power into output power. A first measuring unit measures a value of a first electric parameter depending on the input power. A first determiner determines, from the measured value of the first electric parameter, a first feedback controlled variable. A second measuring unit measures a value of a second electric parameter indicative of the output power, and a calculator calculates, based on the measured value of the second electric parameter and a command value for the second electric parameter, a second feedback controlled variable. A selector selects, based on the measured value of the first electric parameter, one of the first feedback controlled variable and the second feedback controlled variable. A second determiner determines the manipulated variable using the selected one of the first and second feedback controlled variables.

First claim

What is claimed is:

1. A power converter comprising:
a driver that drives a switching element of a switch circuit using a manipulated variable for the switching element to convert input power to the switch circuit into output power of the switch circuit;
a first measuring unit that measures a value of a first electric parameter depending on the input power to the switch circuit;
a first determiner that determines, from the measured value of the first electric parameter, a first feedback controlled variable;
a second measuring unit that measures a value of a second electric parameter indicative of the output power from the switch circuit;
a calculator that calculates, based on the measured value of the second electric parameter and a command value for the second electric parameter, a second feedback controlled variable;
a selector that selects, based on the measured value of the first electric parameter, one of the first feedback controlled variable and the second feedback controlled variable; and
a second determiner that determines the manipulated variable for the switching element using the selected one of the first feedback controlled variable and the second feedback controlled variable.

2. The power converter according to claim 1 , wherein the first feedback controlled variable, the second controlled variable, and the first electric parameter are a same electrical quantity, and the selector is configured to select one of the first feedback controlled variable and the second feedback controlled variable such that the selected one of first feedback controlled variable and the second feedback controlled variable is closer to the measured value of the first electric parameter.

3. The power converter according to claim 2 , wherein:
the first determiner directly determines, from the measured value of the first electric parameter, the first feedback controlled variable that is higher than the measured value of the first electric parameter;
the calculator calculates, based on the measured value of the second electric parameter and the command value for the second electric parameter, the second feedback controlled variable that is higher than the measured value of the first electric parameter; and
the selector is configured to select one of the first feedback controlled variable and the second feedback controlled variable such that the selected one of first feedback controlled variable and the second feedback controlled variable is lower than the other thereof.

4. The power converter according to claim 1 , wherein:
the first measuring unit is configured to measure, as the measured value of the first electric parameter, one of an input current to the switch circuit as the input power and an output current from the switch circuit as the output power; and
the second measuring unit is configured to measure, as the measured value of the second electric parameter, one of an output voltage and the output current from the switch circuit as the output power.

5. The power converter according to claim 1 , wherein:
the first electric parameter is one of an input current to the switch circuit as the input power, and an output current from the switch circuit as the output power;
each of the input current and the output current varies with time; and
the first measuring unit is configured to measure, as the measured value of the first electric parameter, one of a peak value of the input current to the switch circuit as the input power within a predetermined period, and a peak value of the output current from the switch circuit as the output power within the predetermined period.

6. The power converter according to claim 1 , wherein:
the switch circuit is comprised of, as the switching element, a pair of a first switching element and a second switching element connected thereto;
the driver complementarily turns on the first switching element and the second switching element for each predetermined cycle;
the first electric parameter includes at least one of a first input current to the first switching element and a second input current to the second switching element; and
the first measuring unit is configured to measure, as the measured value of the first electric parameter, one of:
one of a peak value of the first input current and a peak value of the second input current; and
an average value of the peak value of the first input current and the peak value of the second input current.

7. The power converter according to claim 1 , wherein:
the first determiner is configured to add a preset value of the first electric parameter to the measured value of the first electric parameter, thus determining the first feedback controlled variable.

8. The power converter according to claim 1 , further comprising:
a change quantity calculator that calculates a change quantity of the measured value of at least one of the first electric parameter and the second electric parameter per unit time;
a third determiner that determines whether the change quantity of the measured value of at least one of the first electric parameter and the second electric parameter per unit time is within a predetermined allowable range; and
a reducing unit that reduces the manipulated variable for the switching element when it is determined that the change quantity of the measured value of at least one of the first electric parameter and the second electric parameter per unit time is out of the predetermined allowable range.

9. The power converter according to claim 8 , wherein:
the reducing unit is configured to subtract, from the manipulated variable for the switching element, a value, and change the value depending on the change quantity of the measured value of at least one of the first electric parameter and the second electric parameter per unit time.

10. The power converter according to claim 1 , wherein:
the switch circuit includes a transformer comprised of a primary winding and a secondary winding magnetically coupled thereto;
the switching element is connected to the primary winding; and
the first measuring unit is configured to measure, as the measured value of the first electric parameter, one of an input current to the primary winding as the input power and an output current from the secondary winding as the output power.

Assignees

• Denso Corp
• Nippon Soken

Inventors

• Kimura Norihito
• Itou Hideki
• Hayashi Yuji

Classifications

• H02M3/33507

  with automatic control of the output voltage or current, e.g. flyback converters (H02M3/33561, H02M3/33569 take precedence) · CPC title

• H02M3/3376 Primary

  with automatic control of output voltage or current · CPC title