Power conversion device and method for diagnosing abnormality in voltage sensor characteristics

Patent metadata

Field	Value
Publication number	US-10014776-B2
Application number	US-201715449191-A
Country	US
Kind code	B2
Filing date	Mar 3, 2017
Priority date	Jul 19, 2016
Publication date	Jul 3, 2018
Grant date	Jul 3, 2018

Abstract

A power conversion device provided with a DC power source, a voltage boost converter, an inverter, a primary smoothing capacitor, a secondary smoothing capacitor, an intermediate capacitor provided in the voltage boost converter and three voltage sensors which measure the voltages of the capacitors, further including an abnormality diagnosis controller which makes a diagnosis of the presence/absence of an abnormality in the detection characteristics of the voltage sensors, on the basis of the state of transition of the detection results of the voltage sensors which are monitored during a discharge operation by the respective capacitors.

First claim

What is claimed is:

1. A power conversion device, comprising:
a voltage boost converter which performs DC/DC conversion of a DC voltage supplied from a DC power source and outputs a boosted DC voltage by switching of a first power semiconductor element group;
an inverter which is connected to a subsequent stage of the voltage boost converter, performs DC/AC conversion of the boosted DC voltage by switching of a second power semiconductor element group, and outputs an AC voltage;
a primary smoothing capacitor which is connected between the DC power source and the voltage boost converter and smoothens the DC voltage supplied to the voltage boost converter;
a secondary smoothing capacitor which is connected between the voltage boost converter and the inverter and smoothens the boosted DC voltage supplied to the inverter;
an intermediate capacitor provided inside the voltage boost converter;
a primary-side voltage sensor which measures a voltage of the primary smoothing capacitor;
a secondary-side voltage sensor which measures a voltage of the secondary smoothing capacitor;
an intermediate voltage sensor which measures a voltage of the intermediate capacitor; and
an abnormality diagnosis controller which:
carries out a process of measuring a detected voltage value of each of the primary-side voltage sensor, the secondary-side voltage sensor and the intermediate voltage sensor, and selecting detected voltage values of two of the primary-side voltage sensor, the secondary-side voltage sensor and the intermediate voltage sensor, multiple times over a passage of time during implementation of an operation of discharging electrical charge inside the primary smoothing capacitor and electrical charge inside the secondary smoothing capacitor;
implements the operation of discharging by controlling the switching of the first power semiconductor element group included in the voltage boost converter and the switching of the second power semiconductor element group included in the inverter; and
upon halting the operation of discharging based on control of the voltage boost converter, makes a diagnosis of a presence or absence of an abnormality in detection characteristics of the primary-side voltage sensor, the secondary-side voltage sensor and the intermediate voltage sensor, based on comparison results of the detected voltage values which are gathered multiple times during the operation of discharging based on control of the inverter.

2. The power conversion device according to claim 1 , wherein the abnormality diagnosis controller:
implements the operation of discharging based on the control of the voltage boost converter and the control of the inverter, in a state in which the DC power source supplied to the voltage boost converter is disconnected; and
halts the operation of discharging, based on the control of the voltage boost converter, when deviation in the detected voltage values becomes equal to or lower than a predetermined deviation threshold value.

3. The power conversion device according to claim 2 , wherein the abnormality diagnosis controller:
halts the operation of discharging based on the control of the inverter, when the detected voltage value of each of the primary-side voltage sensor, the secondary-side voltage sensor and the intermediate voltage sensor gathered during the operation of discharging based on the control of the inverter, upon halting the operation of the discharging based on the control of the voltage boost converter, become less than a predetermined threshold value;
calculates, as one of the comparison results, a sum of absolute values of multiple times of deviation in the detected voltage values which are selected the multiple times; and
determines that there is the abnormality in the detection characteristics when the sum exceeds a predetermined first determination threshold value.

4. The power conversion device according to claim 2 , wherein the abnormality diagnosis controller:
halts the operation of discharging based on the control of the inverter, when the detected voltage value of each of the primary-side voltage sensor, the secondary-side voltage sensor and the intermediate voltage sensor gathered during the operation of discharging based on the control of the inverter, upon halting the operation of the discharging based on the control of the voltage boost converter, become less than a predetermined threshold value;
calculates, as one of the comparison results, an absolute value of the deviation in the detected voltage values which are selected the multiple times, individually for each of the multiple times; and
determines that there is the abnormality in the detection characteristics when any of the absolute value of deviation calculated for each of the multiple times exceeds a predetermined first determination threshold value.

5. The power conversion device according to claim 1 , wherein the abnormality diagnosis controller:
halts the operation of discharging based on the control of the inverter, when the detected voltage value of each of the primary-side voltage sensor, the secondary-side voltage sensor and the intermediate voltage sensor gathered during the operation of discharging based on the control of the inverter, upon halting the operation of the discharging based on the control of the voltage boost converter, become less than a predetermined threshold value;
calculates, as one of the comparison results a sum of absolute values of multiple times of deviation in the detected voltage values which are selected the multiple times; and
determines that there is the abnormality in the detection characteristics when the sum exceeds a predetermined first determination threshold value.

6. The power conversion device according to claim 1 , wherein the abnormality diagnosis controller:
halts the operation of discharging based on the control of the inverter, when the detected voltage value of each of the primary-side voltage sensor, the secondary-side voltage sensor and the intermediate voltage sensor gathered during the operation of discharging based on the control of the inverter, upon halting the operation of the discharging based on the control of the voltage boost converter, become less than a predetermined threshold value;
calculates, as one of the comparison results, an absolute value of deviation in the detected voltage values which are selected the multiple times, individually for each of the multiple times; and
determines that there is the abnormality in the detection characteristics when any of the absolute value of deviation calculated for each of the multiple times exceeds a predetermined first determination threshold value.

7. A power conversion devise, comprising:
a voltage boost converter which performs DC/DC conversion of a DC voltage supplied from a DC power source and outputs a boosted DC voltage by switching of a first power semiconductor element group;
an inverter which is connected to a subsequent stage of the voltage boost converter, performs DC/AC conversion of the boosted DC voltage by switching of a second power semiconductor element group, and outputs an AC voltage;
a primary smoothing capacitor which is connected between the DC power source and the voltage boost converter and smoothens the DC voltage supplied to the voltage boost converter;
a secondary smoothing capacitor which is connected between the voltage boost converter and the inverter and smoothens the boosted DC voltage supplied to the inverter;
an intermediate capacitor provided inside the voltage boost converter;
a primary-side voltage sensor which measures a voltage of the primary smoothing capacitor;
a secondary-side voltage sensor which measures a voltage of the secondary smoothing capacitor;
an intermediate voltage sensor wh

Assignees

• Mitsubishi Electric Corp

Inventors

• Kobayashi Masaru
• Idenoue Shinsuke
• Ishii Satoshi
• Otsuka Kazuhiko
• Abe Junichi

Classifications

• G01R31/2829

  Testing of circuits in sensor or actuator systems (testing of apparatus for measuring electric or magnetic variables G01R35/00; testing of indicating or recording apparatus G01D; in airbag systems B60R21/0173; checking gas analysers G01N33/007; monitoring or fail-safe circuits for electromagnets H01F7/1844) · CPC title

• H02M3/158 Primary

  including plural semiconductor devices as final control devices for a single load · CPC title

• G01R19/003

  Measuring mean values of current or voltage during a given time interval · CPC title

• H02P27/06

  using DC to AC converters or inverters (H02P27/05 takes precedence) · CPC title

• H02M1/32

  Means for protecting converters other than automatic disconnection · CPC title