Power-factor correction device for variable speed drive

• US 7,420,351 B2
• Filed: 11/13/2006
• Issued: 09/02/2008
• Est. Priority Date: 11/22/2005
• Status: Expired due to Fees

• Current Assignee: Schneider Toshiba Inverter Europe SAS (Toshiba Corporation)
• Original Assignee: Schneider Toshiba Inverter Europe SAS (Toshiba Corporation)
• Inventors: Grbovic, Petar
• Primary Examiner(s): IP, SHIK LUEN PAUL
• Application Number:
  US11/559,077
• Publication Number:
  US 20070114962A1
• Time in Patent Office: 659 Days
• Field of Search: 318/772, 318/803, 318/771, 318/770, 219/130.1, 322/19, 322/28, 322/36, 322/222
• US Class Current: 318/772
• CPC Class Codes: H02M 1/4225 using a non-isolated boost converter
• CPC Class Codes: H02P 2201/15 Power factor Correction [PFC] circuit generating the DC link voltage for motor driving inverter motor power factor control H02P23/26
• CPC Class Codes: H02P 27/08 with pulse width modulation
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
• CPC Class Codes: Y02P 80/10 Efficient use of energy, e.g. using compressed air or pressurized fluid as energy carrier

Abstract

A variable speed drive for a three-phase electric motor, including a rectifier module supplying a rectified voltage from a single-phase alternating current network, a voltage step-up module supplying a regulated bus voltage, and an inverter module supplying a control voltage to the motor. The variable speed drive includes a hybrid power-factor correction device that drives the voltage step-up module and that includes a digital circuit including a voltage step-up module supplying a correction signal based on a measurement signal of the bus voltage and an analog circuit supplying a driver signal to the step-up module based on a measurement signal of the rectified voltage and based on the correction signal.

Claims

1. A variable speed drive for a three-phase electric motor, comprising:

a rectifier module that supplies a rectified voltage from a single-phase alternating current electrical network;

a voltage step-up module that supplies a regulated bus voltage from the rectified voltage;

an inverter module powered by the bus voltage and that supplies a control voltage to the three-phase electric motor from a control set-point;

a digital processing unit that supplies the control set-point; and

a hybrid power-factor correction device that drives the voltage step-up module and that comprises;

a digital circuit including a voltage regulator module that receives a measurement signal of the bus voltage from the voltage step-up module and that supplies a correction signal based on the received measurement signal of the bus voltage, and

an analog circuit that receives a measurement signal of the rectified voltage from the rectifier module, that receives the correction signal from the digital circuit, and that supplies a driver signal to the step-up module based on the received measurement signal of the rectified voltage and the received correction signal.

2. A variable speed drive according to claim 1, wherein the digital circuit is incorporated in the processing unit.

3. A variable speed drive according to claim 1, wherein the correction signal is a pulse width modulation (PWM) signal.

4. A variable speed drive according to claim 1, wherein the step-up module includes a solid-state switch actuated by the driver signal.

5. A variable speed drive according to claim 4, wherein the analog circuit includes a limiter circuit that receives as an input the measurement signal of the rectified voltage and that generates as an output a clipped signal of roughly trapezoidal form.

6. A variable speed drive according to claim 5, wherein the limiter circuit includes a resistor divider bridge and a limiting diode including an anode connected to a mid-point of the divider bridge.

7. A variable speed drive according to claim 5, wherein the analog circuit further includes a switching circuit that receives as an input the clipped signal and the correction signal to generate a current reference signal.

8. A variable speed drive according to claim 7, wherein the analog circuit further includes a hysteresis-type current regulator that receives as an input the current reference signal and a current measurement signal to deliver as an output the driver signal to the solid-state switch.

9. A variable speed drive according to claim 8, wherein the voltage regulator module forces the current regulator to deliver a driver signal ordering the solid-state switch to open in absence of a variable speed drive load current.

10. A variable speed drive according to claim 9, wherein the digital circuit receives a measurement signal representative of the variable speed drive load current.