Power conversion apparatus

• US 9,214,881 B2
• Filed: 01/18/2012
• Issued: 12/15/2015
• Est. Priority Date: 01/18/2011
• Status: Active Grant

• Current Assignee: Daikin Industries Ltd
• Original Assignee: Daikin Industries Ltd
• Inventors: Sekimoto, Morimitsu, Taniguchi, Tomoisa, Hibino, Hiroshi, Maeda, Toshiyuki
• Primary Examiner(s): Leykin, Rita
• Application Number:
  US13/980,241
• Publication Number:
  US 20130300327A1
• Time in Patent Office: 1,427 Days
• Field of Search: 318/400.23, 318/400.24, 318/400.25, 318/438, 318/807, 318/808, 318/599, 318/503, 318/729, 318/400.27
• US Class Current: 1/1
• CPC Class Codes: H02M 1/12 Arrangements for reducing harmonics from ac input or output
• CPC Class Codes: H02P 1/16 for starting dynamo-electric motors or dynamo-electric converters
• CPC Class Codes: H02P 21/05 specially adapted for damping motor oscillations, e.g. for reducing hunting
• CPC Class Codes: H02P 6/10 Arrangements for controlling torque ripple, e.g. providing reduced torque ripple

Abstract

A DC link is provided, which includes a capacitor connected in parallel to an output of a converter circuit, and outputs a pulsating DC link voltage. An inverter circuit is provided, which converts an output of the DC link to AC by switching, and supplies the AC to a motor connected thereto. A controller is provided, which controls switching of the inverter circuit so that motor currents pulsate in synchronization with pulsation of a power-supply voltage. The controller controls the switching of the inverter circuit in accordance with a load of the motor or an operational state of the motor, and reduces pulsation amplitude of the motor currents.

Claims

1. A power conversion apparatus comprising:

a converter circuit configured to perform full-wave rectification of a power-supply voltage of an AC power supply;

a DC link including a capacitor connected in parallel to an output of the converter circuit and configured to output a pulsating DC voltage;

an inverter circuit configured to convert an output of the DC link to AC by switching, and supplies the AC to a motor connected thereto; and

a controller configured to control the switching so that currents of the motor pulsate in synchronization with pulsation of the power-supply voltage, wherein

the controller controls the switching in accordance with reduction in a load of the motor, and reduces pulsation amplitude of the currents.

2. The power conversion apparatus of claim 1, wherein

the controller reduces the pulsation amplitude in accordance with at least one of the currents, electric power, speed, or a torque of the motor.

3. The power conversion apparatus of claim 1, wherein

the controller controls the switching so that the DC voltage is higher than zero, and reduces the pulsation amplitude.

4. The power conversion apparatus of claim 1, wherein

the controller reduces the pulsation amplitude at start-up of the motor.

5. The power conversion apparatus of claim 4, wherein

the controller gradually increases the pulsation amplitude after the start-up of the motor.

6. The power conversion apparatus of claim 1, wherein

the controller includes a current controller performing at least one of proportional control, integral control, or derivative control to reduce deviation of reference values of the currents from actual current values, and changes a control gain of the control when reducing the pulsation amplitude.

7. The power conversion apparatus of claim 2, wherein

the controller controls the switching so that the DC voltage is higher than zero, and reduces the pulsation amplitude.