Power conversion device

Patent metadata

Field	Value
Publication number	US-2016308461-A1
Application number	US-201415100711-A
Country	US
Kind code	A1
Filing date	Jan 9, 2014
Priority date	Jan 9, 2014
Publication date	Oct 20, 2016
Grant date	—

Abstract

A power conversion device converts three-phase AC power into DC power by two-arm PWM modulation control and includes a main circuit that is constituted by a plurality of switching elements that are bridge-connected therein; a voltage-command generation unit that generates a voltage command value for the main circuit; a current detection unit that detects at least one of output currents of the main circuit; a power-factor calculation unit that calculates a power factor on the basis of the output current and the voltage command value; a carrier-signal generation unit that generates a carrier signal of a frequency corresponding to the power factor; and a PWM-signal generation unit 6 that compares the voltage command value and the carrier signal to generate a PWM signal that executes switching control on the switching elements.

First claim

1 . A power conversion device that converts DC power into three-phase AC power by using two-arm PWM modulation control, the power conversion device comprising:
a main circuit that is constituted by a plurality of switching elements that are bridge-connected therein; a voltage-command generation unit that generates a voltage command value for the main circuit; a current detection unit that detects at least one of output currents of the main circuit; a power-factor calculation unit that calculates a power factor on the basis of the output current and the voltage command value; a carrier-signal generation unit that generates a carrier signal of a frequency corresponding to the power factor; and a PWM-signal generation unit that compares the voltage command value and the carrier signal so as to generate a PWM signal that executes switching control on the switching elements.

2 . A power conversion device that converts three-phase AC power into DC power by two-arm PWM modulation control, the power conversion device comprising:
a main circuit that is constituted by a plurality of switching elements that are bridge-connected therein; a voltage-command generation unit that generates a voltage command value for the main circuit; a current detection unit that detects at least one of input currents of the main circuit; a power-factor calculation unit that calculates a power factor on the basis of the input current and the voltage command value; a carrier-signal generation unit that generates a carrier signal of a frequency corresponding to the power factor; and a PWM-signal generation unit that compares the voltage command value and the carrier signal so as to generate a PWM signal that executes switching control on the switching elements.

3 . The power conversion device according to claim 1 , wherein
the carrier-signal generation unit calculates the frequency of the carrier signal on the basis of a relation between the power factor and the frequency of the carrier signal.

4 . The power conversion device according to claim 1 , wherein
the carrier-signal generation unit reduces the frequency of the carrier signal as the power factor approaches 0.

5 . A power conversion device that converts DC power into three-phase AC power by two-arm PWM modulation control, the power conversion device comprising:
a main circuit that is constituted by a plurality of switching elements that are bridge-connected therein; a voltage-command generation unit that generates a voltage command value for the main circuit; a current detection unit that detects at least one of output currents of the main circuit; a power-factor calculation unit that calculates a power factor on the basis of the output current and the voltage command value; a carrier-signal generation unit that generates a carrier signal; a current-protection-level calculation unit that calculates a current protection level corresponding to the power factor; a PWM-signal generation unit that compares the voltage command value and the carrier signal so as to generate a PWM signal that executes switching control on the switching elements; and a current-protection monitoring unit that stops an operation of the main circuit when the output current exceeds the current protection level.

6 . A power conversion device that converts three-phase AC power into DC power by two-arm PWM modulation control, the power conversion device comprising:
a main circuit that is constituted by a plurality of switching elements that are bridge-connected therein; a voltage-command generation unit that generates a voltage command value for the main circuit; a current detection unit that detects at least one of input currents of the main circuit; a power-factor calculation unit that calculates a power factor on the basis of the input current and the voltage command value; a carrier-signal generation unit that generates a carrier signal; a current-protection-level calculation unit that calculates a current protection level corresponding to the power factor; a PWM-signal generation unit that compares the voltage command value and the carrier signal so as to generate a PWM signal that executes switching control on the switching elements; and a current-protection monitoring unit that stops an operation of the main circuit when the input current exceeds the current protection level.

7 . The power conversion device according to claim 5 , wherein
the current-protection-level calculation unit calculates the current protection level on the basis of a relation between the power factor and current information indicating the current protection level.

8 . The power conversion device according to claim 5 , wherein
the current-protection-level calculation unit lowers the current protection level as the power factor approaches 0.

9 . A power conversion device that converts DC power into three-phase AC power by two-arm PWM modulation control, the power conversion device comprising:
a main circuit that is constituted by a plurality of switching elements that are bridge-connected therein; a temperature detection unit that detects a temperature of the main circuit; a voltage-command generation unit that generates a voltage command value for the main circuit; a current detection unit that detects at least one of output currents of the main circuit; a power-factor calculation unit that calculates a power factor on the basis of the output current and the voltage command value; a carrier-signal generation unit that generates a carrier signal; an overheat-protection-level calculation unit that calculates an overheat protection level corresponding to the power factor; a PWM-signal generation unit that compares the voltage command value and the carrier signal so as to generate a PWM signal that executes switching control on the switching elements; and an overheat-protection monitoring unit that stops an operation of the main circuit when the temperature of the main circuit exceeds the overheat protection level.

10 . A power conversion device that converts three-phase AC power into DC power by two-arm PWM modulation control, the power conversion device comprising:
a main circuit that is constituted by a plurality of switching elements that are bridge-connected therein; a temperature detection unit that detects a temperature of the main circuit; a voltage-command generation unit that generates a voltage command value for the main circuit; a current detection unit that detects at least one of input currents of the main circuit; a power-factor calculation unit that calculates a power factor on the basis of the input current and the voltage command value; a carrier-signal generation unit that generates a carrier signal; an overheat-protection-level calculation unit that calculates an overheat protection level corresponding to the power factor; a PWM-signal generation unit that compares the voltage command value and the carrier signal so as to generate a PWM signal that executes switching control on the switching elements; and an overheat-protection monitoring unit that stops an operation of the main circuit when the temperature of the main circuit exceeds the overheat protection level.

11 . The power conversion device according to claim 9 , wherein
the overheat-protection-level calculation unit calculates the overheat protection level on the basis of a relation between the power factor and temperature information indicating the overheat protection level.

12 . The power conversion device according to claim 9 , wherein
the overheat-protection-level calculation unit lowers the overheat protection level as the power factor approache

Assignees

• Mitsubishi Electric Corp

Inventors

• Taira Satoshi

Classifications

• H02M7/44 Primary

  by static converters · CPC title

• H05K7/20909

  Forced ventilation, e.g. on heat dissipaters coupled to components · CPC title

• H02H7/122 Primary

  for inverters, i.e. DC/AC converters · CPC title

• H02P27/08

  with pulse width modulation · CPC title

• H02M1/08

  Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters · CPC title