HEF4752V Просмотр технического описания (PDF) - Philips Electronics

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производитель

HEF4752V

A.C. motor control circuit

Philips Electronics 

Philips Semiconductors

A.C. motor control circuit

Product specification

HEF4752V

LSI

APPLICATION INFORMATION

Figure 2 shows the functional block diagram of a 3-phase

a.c. motor speed control system using a thyristorized

inverter with variable frequency output. The inverter

control signals are generated by the HEF4752V

(PWM-IC). A special feature of the PWM (Pulse-Width

Modulation) - IC is here, that the motor is supplied by

sinoidally modulated pulses, hence the resulting motor

current will approach a sine-wave with a minimum on

higher harmonics. In this way, an optimum speed drive

with high performance is obtained.

Furthermore, the HEF4752V contains all logic circuitry

required for this special waveform generation, so that the

amount of control circuit components is reduced

considerable. The speed drive system in Fig.2 is controlled

by the analogue control section.

The FCT and VCT clock pulse oscillators are driven in

such a way, that a fast response speed control of the a.c.

motor is obtained, depending on: the reference values for

speed; motor voltage; motor current (Limited by the

measured motor current via DCCT - d.c. current

transformer -); the increasing value of VCb during braking

action.

Fig.2 PWM motor speed control system using HEF4752V.

January 1995

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