SU777818A1 - Switching filter - Google Patents

Description

(54) SWITCHING FILTER

The invention relates to electrical engineering, it can be used in automatic control systems with single-phase valve rectifiers for measuring the average value of their control pulse signals.

Known switching filters that contain integrators connected to ring switches 1.

Their disadvantage is low speed.

In addition, switching filters are known that contain integrators connected to switches, a clock generator, an amplifier, and OR 2 elements.

The disadvantages of this device are the low speed caused by the time separation of the integrators' intervals and the high static error due to the nonidentity of the characteristics of the device blocks.

In order to reduce static leakage and improve speed, a switching filter containing an integrator connected to a switch, the control inputs of which are connected to a clock generator, and an input signal source, a diode smoothing C-circuit and a threshold element, with the output source of input signals through A diode connected in series and an integrator is connected to the input of a smoothing KS circuit, the output of which is connected to the switch and, via a threshold element, to the output bus.

FIG. 1 shows a circuit diagram of a commercial filter; in fig. 2 - switching operation schedule.

ten

The filter contains an integrator /, smoothing YAS-Lip 2, a source of 3 input signals, a switch 4, a clock generator 5, a threshold element 6, a diode 7 and an output (output bus) 8.

15

FIG. 2 shows the time schedules of the switching filter, where:

a) a plot of the change in the duty cycle of the source 3 impulse signals;

b) a graph of the variation of the output voltages of the integrator /, smoothing RC circuit 2 and the threshold level of the response of element 6;

c) clock pulses of the generator 5;

d) a graph of the change in the output voltage at outlet 8.

The filter works as follows.

In the established mode of operation, at each measurement interval with the duration T, set by the clock generator 5, short-term installation of the initial zero conditions of the integrator 1 and the / C-circuit 2 takes place via the switch 4 (Fig. 26, c). Then, on the integrator / pr., A measurement is made of the average value of the SERIES of pulses coming from the source 3 of the input signals through the diode 7 following the period T and the variable duty cycle, while the voltage on the integrator 1 increases in steps in the tact interval T (Fig. 2b) . The voltage on RC circuit 2, connected to the output of the integrator /, also increases in the tact interval T (Fig. 2b): And it has almost linear growth rate at, i.e., a sufficiently large frequency / I / T of source 5 pulses compared to clock generator 5.

At moments (1 or a. In Fig. 2b, d) the magnitude of the rising voltage of C-chain 2 coincides with the threshold of element 6, its output voltage increases in steps, and output pulses are generated to bus 8.

The introduction of a smoothing C-circuit 2 and a threshold element allows for the conversion of the average value of the input TCHI-modulated impulse signal of an increased tracking frequency f 1 / t to the phase-pulse output signal following the low repetition frequency / 1 / T and phase a with the average value (duty ratio) of the pulse signal of the source 3. At the same time, the measurement operations of the readout are performed simultaneously at each interval T of the filter operation, which increases its speed and reduces the static reshnost.

Claims (2)

1. Shipillo V. P., Automated valve electric drive. M., "Energy, 1969, p. 190, fig. 4-8. 2. USSR author's certificate number 587619, cl. H 03 K 17/02, 05/27/76.