Power conversion device

Patent metadata

Field	Value
Publication number	US-12244248-B2
Application number	US-202318306569-A
Country	US
Kind code	B2
Filing date	Apr 25, 2023
Priority date	May 31, 2022
Publication date	Mar 4, 2025
Grant date	Mar 4, 2025

Abstract

A setting unit sets a duty ratio of a PWM signal based on a target voltage value, and outputs the duty ratio to a voltage conversion circuit. An estimated value calculation unit cyclically calculates an estimated duty ratio value based on the detected input voltage value and the detected output voltage value. An abnormality detection unit cyclically calculates, as a difference value, a difference between an updated estimated value and a comparison reference value, and detects abnormality of a voltage detection unit based on a change in calculated difference value. The updated estimated value is a newly calculated estimated duty ratio value. The comparison reference value is a value based on the estimated duty ratio value calculated in a cycle prior to a cycle in which the updated estimated value is calculated.

First claim

What is claimed is:

1. A power conversion device, comprising:
a voltage conversion circuit;
voltage detection circuitry including:
an input voltage detector configured to detect, as a detected input voltage value, an input voltage input to the voltage conversion circuit; and
an output voltage detector configured to detect, as a detected output voltage value, an output voltage output from the voltage conversion circuit; and

control circuitry configured to control the voltage conversion circuit,
the control circuitry including:
setting circuitry configured to set, based on a target voltage value which is a target value of the output voltage, a duty ratio of a PWM signal to be given to the voltage conversion circuit, and configured to output the PWM signal based on the set duty ratio to the voltage conversion circuit;
estimated value calculation circuitry configured to cyclically calculate, based on the detected input voltage value and the detected output voltage value, an estimated duty ratio value which is a duty ratio of the PWM signal supposed to be output from the setting circuitry to the voltage conversion circuit with a premise of a relationship between the detected input voltage value and the detected output voltage value; and
abnormality detection circuitry configured to detect abnormality of the voltage detection circuitry based on a change of a difference value, the difference value being a cyclically calculated difference between an updated estimated value and a comparison reference value, the updated estimated value being the estimated duty ratio value newly calculated by the estimated value calculation circuitry, the comparison reference value being based on the estimated duty ratio value calculated by the estimated value calculation circuitry in a cycle prior to a cycle in which the updated estimated value is calculated.

2. The power conversion device according to claim 1 , wherein the comparison reference value is the estimated duty ratio value acquired in a cycle that immediately precedes the cycle in which the updated estimated value is acquired.

3. The power conversion device according to claim 1 , wherein the comparison reference value is an average value of a plurality of the estimated duty ratio values acquired in cycles that precede the cycle in which the updated estimated value is acquired.

4. The power conversion device according to claim 1 , wherein the abnormality detection circuitry is configured to determine that the voltage detection circuitry has abnormality when, after the difference value is detected to have exceeded a predetermined range, the cyclically calculated difference value is detected to have fallen within the predetermined range a predetermined number of times in succession.

5. The power conversion device according to claim 4 , wherein the abnormality detection circuitry is configured to set the predetermined range based on the input voltage input to the voltage conversion circuit and the output voltage output from the voltage conversion circuit.

6. The power conversion device according to claim 4 , wherein the predetermined range is set based on a maximum value of a duty ratio gap width, the duty ratio gap width being a width of a gap between the duty ratio set based on the target voltage value and on the detected output voltage value, and the estimated duty ratio value, in a normal operation range of the voltage detection circuitry.

7. The power conversion device according to claim 1 , wherein the abnormality detection circuitry is configured to temporarily end determination about whether the voltage detection circuitry has abnormality when the difference value is detected, in succession, to have exceeded a predetermined range, and the difference value exceeds the predetermined range at polarities opposite from each other in two occurrences of the exceeding detected in succession.

8. The power conversion device according to claim 1 , wherein the abnormality detection circuitry is configured to temporarily disable detection of the abnormality when the target voltage value is changed.

9. The power conversion device according to claim 1 , wherein the abnormality detection circuitry is configured to temporarily disable detection of the abnormality when a change in load causes an output current of the voltage conversion circuit to change by an amount equal to or greater than a predetermined current value.

10. The power conversion device according to claim 1 , wherein the abnormality detection circuitry is configured to temporarily disable detection of the abnormality when a change in voltage of an external power source causes the input voltage to change by an amount equal to or greater than a predetermined voltage value.

Assignees

• Mitsubishi Electric Corp

Inventors

• Fujioka Kazuhiro
• Ishiguro Yoshiaki
• Kondo Ryota

Classifications

• H02M1/4225

  using a non-isolated boost converter · CPC title

• H02M1/32

  Means for protecting converters other than automatic disconnection · CPC title

• H02M7/4803

  with means for reducing DC component from AC output voltage · CPC title

• H02M1/0025

  Arrangements for modifying reference values, feedback values or error values in the control loop of a converter · CPC title

• H02M1/0019

  the disturbance parameters being load current fluctuations · CPC title