초록 ▼

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 variab

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.

대표청구항 ▼

The invention claimed is: 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 voltag

The invention claimed is: 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.