SU1707753A1 - Pulse-length modulator - Google Patents

Abstract

The invention relates to electrical engineering. The purpose of the invention is to increase reliability by improving the symmetry of the output pulses. The device contains a master and slave pulse generators 1, 8 and a phase-shifting unit 5. Thanks to the introduction of the first and second NAND logic elements, the OR logic element and the first and second pulse shapers 2, 3, the control goes through one channel, thus achieving the goal. 2 Il.

Description

1

The invention relates to electrical engineering, in particular, to converter equipment for converting mains voltage to an alternating or constant desired level, and can be used in the development of secondary power sources.

A device for controlling a pulse regulator is known, comprising two oscillators and a phase shifter made using a magnetic amplifier.

The drawback of the device is the manufacturing complexity, determined by the complexity of manufacturing the magnetic amplifier.

The closest in technical essence to the present invention is a phase control method of a pulse regulator, which is implemented using a device containing a master and a slave generator and two phase-shifting devices, the outputs of which are connected to the control inputs of the slave generator.

A disadvantage of the known device is the asymmetry of the duration of the half-periods of the output signal of the slave generator, due to the spread of parameters of the inverter, integrators and comparators of phase-shifting devices.

The aim of the invention is to increase reliability by improving the symmetry of the output pulses.

The goal is achieved by the fact that a pulse-width modulator containing a master and a slave pulse generator, the first outputs of which are connected respectively to the first and second output terminals, the slave pulse generator having a control input, and a phase-locking unit and the second pulse shaper, the logical element OR, the first and second logic elements AND-NOT, with the first and second outputs of the master generator of pulses through the first and second pulse shapers connected to the first and the second the inputs of the logical element OR, whose output through the phase-shifting unit is connected to the first input of the first logical element AND-NOT, the output of which is connected to the control input of the slave pulse generator, the second input of the first logical element AND-NOT connected to the output of the second logical element AND-NOT, the first and second inputs of which are connected respectively to the first output terminal and the second output of the slave pulse generator.

The essence of the invention is. that the slave generator is controlled from a single phase-shifting unit with a double frequency of the leading pulse generator, while the location of the output pulses on the time axis is fixed by the AND-NES logic element, whose inputs are controlled by the output signals of both pulse generators. This allows one phase-moving unit to be eliminated, and thereby eliminating the variation of parameters affecting the switching moment of the threshold element of the phase-shifting unit.

Fig. 1 is a schematic diagram of the modulator; Figure 2 shows signal plots explaining the principle of operation.

The modulator contains a master generator 1 pulses, the first 2 and second 3 pulse shapers, the logical element OR 4, the phase-shifting unit 5, the first 6 and the second 7 logical elements AND-NOT and the slave generator 8 pulses, and the out-of-phase outputs of the master generator 1 pulses through the first 2 and second 3 pulse generators are connected to an OR 4 gate connected to the control input of the phase-shifting unit 5, the output of which through the first logic element AND-NOT 6 is connected to the control input of the slave generator 8 and pulses, the two inputs of the second logic AND-NO element 7 are connected to the outputs of the master 1 and the slave pulse generators 8.

The modulator operates as follows.

When the device is turned on, the master pulse generator 1 generates a signal Ui at the anti-optical outputs. These pulses through the first 2 and second 3 pulse shapers (for example, differentiating chains) are fed to the input of an OR OR 4. The output of which produces pulses W. These signals trigger the sawtooth generator of the phase-shifting unit 5, which has signals at the output, which control through the first logical element AND-NOT 6 slave generator of 8 pulses. The unambiguity of the position of the output signal Us of the slave generator 8 pulses relative to the signal of the master oscillator 1 pulses is controlled by them through the second logic element AND-HE 7, to the control inputs of which they are connected.

In the known device, two sawtooth voltage generators and two comparators are used for this. The slope of the sawtooth voltage and the threshold of the comparators may vary depending on the parameters of the elements of which they are composed. This leads to the asymmetry of the half-cycles of the output signal of the slave generator 8 pulses. The control using such signals by the pulse controller, for example, In the form of an amplifier with a transformer output, it can lead to unilateral magnetization of the transformer cores and, consequently, to an increase in the current through the amplifying element, which can cause its failure.

In the proposed modulator, this asymmetry of the half-cycles of the output signal of the slave generator is absent, since the control goes through one channel, which is achieved by using additional elements and the corresponding connections.

The use of the invention will improve the reliability of the pulse controllers controlled by the proposed device.

Claims (1)

Invention Formula Pulse width modulator containing master and slave generators pulses, the first outputs of which are connected respectively to the first and second output terminals, the slave pulse generator having a control input, and a phase shifting unit, characterized in that, in order to increase reliability by improving the symmetry of the output pulses, the first and second pulse drivers, the logical element OR and the first and second logical elements AND-NOT, the first and second outputs of the master pulse generator through the first and second pulse shapers connected to the first and second inputs of the OR, whose output through the phase-shifting unit is connected to the first input of the first logical element AND-NOT, the output of which is connected to the control input of the slave pulse generator, the second input of the first logical element AND-NOT is connected to the output of the second logical element IS-NOT, the first and the second inputs of which are connected respectively to the first output terminal and the second output of the slave pulse generator.