Electric power converting apparatus

Abstract

A three-phase electric power converting apparatus for driving a DC electric motor (3) having a field coil (4), wherein a plurality of semiconductor switching elements having a three-phase electric power conversion function as well as a plurality of smoothing capacitors (14a1,14a2) are series connected between P / N buses between which a DC voltage is applied. The DC electric motor is driven by a chopper operation of an armature chopper unit (13a) composed of a plurality of semiconductor switching elements having a two-phase electric power conversion function. A feedback circuit element (14d) as well as the field coil is connected between a field chopper unit (13b) composed of a plurality of semiconductor switching elements having a remaining-one-phase electric power conversion function and a junction (14c) between the foregoing smoothing capacitors. The voltage at the foregoing junction is caused by a chopper operation of the field chopper unit to flow through the field coil, while the energy stored in the field coil is fed back to the junction through the feedback circuit element.

Description

technical field [0001] The present invention relates to a power conversion device using a semiconductor switching element including an IGBT (Insulated Gate Bipolar Transistor) and the like and having a three-phase power conversion function. Background technique [0002] In the existing elevator system, although the elevator drive (specifically the elevator car drive) adopts a large-scale DC motor, no new type of DC motor is currently used, and most of them use three-phase AC induction motors or permanent magnet motors. But on the other hand, there are still a large number of elevator systems that still use old-fashioned DC motors without improvement, some of which have been in operation for 20 years or even longer, and are getting old day by day. [0003] Therefore, the aging elevator system as mentioned above was gradually updated. However, considering the budget, construction time, and demolition space, the final solution was to keep the DC mo...

AI Technical Summary

Problems solved by technology

[0014] Furthermore, a three-phase converter device or a three-phase inverter device is usually used as a power conversion device, but among them, the armature chopper device 53 only uses a two-phase power conversion function, so there is a problem that the remaining one phase is completely redundant.

[0015] Secondly, the latter does not require the power conversion device of the excitation control unit. With the increase in speed and capacity of the DC motor 55, the induced voltage of the motor 55 increases and the DC power supply voltage becomes larger, so the excitation voltage is higher than that of the DC power supply voltage. The rated voltage of the coil 57 will become smaller, and a larger voltage load will be applied to the excitation coil 57, which may cause the insulation of the excitation coil 57 to deteriorate and be damaged.

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