Abstract:
A variable-frequency drive that includes a DC power supply bus with a positive line and a negative line, and an inverter module powered by the DC bus for supplying a variable voltage to an electric load. The inverter includes a first DC/DC converter including output terminals connected in series on the positive line of the DC bus, a second DC/DC converter including input terminals connected between the positive line and the negative line of the DC bus, a filtering capacitor connected in parallel to the input terminals of the first converter and to the first output terminals of the second converter, and an electric power storage module connected in parallel to the second output terminals of the second converter.
Abstract:
The invention relates to a variable speed drive for three-phase electric motor, comprising a rectifier module (10) supplying a rectified voltage (15) from a single-phase alternating current network, a voltage step-up module (40) supplying a regulated bus voltage (45), an inverter module (50) supplying a control voltage to the motor (M). The variable speed drive comprises a hybrid power-factor correction device which drives the voltage step-up module and which comprises a digital circuit (30) provided with a voltage step-up module supplying a correction signal based on a measurement signal of said bus voltage and an analogue circuit (20) supplying a driver signal (25) to the step-up module based on a measurement signal of said rectified voltage and based on said correction signal.
Abstract:
The invention relates to a current-source power converter comprising, in a module thereof , switching legs having normally-on field effect transistors each controlled by a gate control device. A normally-open auxiliary switch is in series with the switching legs and connected to the positive line of the power supply bus. This auxiliary switch can prevent the mains from short-circuiting during start-up or during malfunction of the auxiliary power supply.
Abstract:
The invention relates to a gate control device for a JFET-type transistor that has a gate, a drain and a source. The gate control device includes a voltage generation circuit comprising an output connected to the gate of the transistor, where the circuit is designed to generate at the output a reference gate-source voltage following a predetermined voltage ramp. A voltage limiting circuit is designed to limit the reference gate-source voltage to a predetermined maximum value when the gate-source voltage at the terminals of the JFET transistor has reached said maximum value.
Abstract:
The invention relates to a switched-mode power supply system comprising two buffer capacitors connected in series and connected between the two input terminals of a DC input voltage source, two switches connected in series, a primary inductive assembly connected in series with the two switches, and a secondary winding magnetically coupled to the primary inductive assembly in order to deliver a DC output voltage. A current injection module injects current at a mid-point of the two buffer capacitors in order to generate a current imbalance at this mid-point. A balancing circuit for balancing the leakage currents of the capacitors, one end of said balancing circuit being connected to the mid-point of the buffer capacitors, maintains this imbalance at a predetermined value. The invention also relates to a speed variator using such a power supply system.