SU771816A1 - Device for smoothing rectified voltage pulsations - Google Patents

Description

one

This invention relates to electrical engineering and can be used in direct current power supply circuits.

Smoothing filters of rectified voltage are known, which contain capacitors in parallel arms and inductance in series arm 1. It is also known that the smoothing effect of such filters can be improved only by increasing the capacitance of the capacitors or the inductance value, which is associated with an increase in its dimensions and weight.

Transistor smoothing filters are also used to smooth out ripples of rectified voltage, providing large smoothing factors with relatively small dimensions 2. But they also weaken the constant component of the voltage and therefore have low efficiency. The use of complex multi-point chokes in inductive-capacitive filters gives a noticeable effect, but leads to complication and cost of the filter.

The prototype of the proposed device is a device for smoothing the pulsations of a rectified voltage, containing a choke connected between the input and output terminals and two capacitors, one of which is connected in parallel to the output terminals and the second one is connected to one of the input terminals 3.

, Depending on the inductance ratios and capacitances, this device may create a capacitive or inductive nature of the load to the rectifier. When working on a capacitive load, the rectifier valves always operate with a current cut-off and experience large impulse loads. When operating at an inductive load, the external characteristic of the rectifier is more stable, but the ripple factor at its output is approximately a dozen times higher than with a capacitive filter. To reduce pulsations at the output of the filter, for energy and economic reasons, it is always preferable to increase the capacitance of the capacitor than the inductance value, since the energy loss in the capacitor is negligible. But with small load resistances, the required capacitor capacitance becomes unacceptably large and, from design considerations, the parallel filter arm is eliminated, which leads to a VHP pulsation and a decrease in the filter efficiency.

The purpose of the invention is to increase the efficiency of the device.

This goal is achieved by the fact that in a device for smoothing pulsations of rectified voltage, containing a choke connected between the input and output terminals, and two capacitors, one of which is connected in parallel to the output terminals, and the second one is connected to one of the input terminals, The other 0 terminal of the second capacitor is connected to another input terminal through a chain consisting of a counter-parallel-connected diode and a dynistor, the polarity of the latter being connected to the opposite polarity of the rectified voltage and input vyNa FIG. 1 is a schematic diagram of the device; in fig. 2 - diagrams of voltage pulsations. The input capacitor 1 is connected by one of its terminals to the common bus of the filter, and the other terminal is connected via a counter-parallel-connected diode 2 to the dynistor 3 to the positive input. Diode 2 is connected according to, and distor 3 is opposite to the polarity of the source of high voltage. The output capacitor 4 is connected in parallel to the output pins. A choke 5 is connected between the positive input terminal and the positive output terminal. FIG. 2 shows: U i is the input voltage of the device; Uz is the voltage across the plates of the input capacitor 1; UZ is the output voltage of the device. At each pulsation period at the output of the rectifier, the capacitor 1 is charged to an amplitude value through an open diode 2 — moments from t to t g of the U curve. holding a constant voltage equal to the amplitude voltage. Until the opening of the dynistor 3, the current through the inductance of the drossel 5 continues to flow directly from the rectifier. When the voltage on

the input of the device (the output of the rectifier) U becomes less than the voltage on the capacitor 1 by the amount of the switching voltage of the dynistor 3, the latter opens (time t h) and the input voltage increases abruptly to an amplitude value, and only after that the input capacitor begins to discharge through inductance 5 to the load.

Claims (3)

The delay in the start of the discharge of the input capacitor 1 and the use of the input voltage source during this delay is equivalent to some increase in the capacitor capacitance. This, as well as the fact that the edges of the pulsations at the input become steeper, leads to a decrease in the pulsations of the voltage at the output of the device to reduce the pulsations of the rectified voltage. The use of the proposed solution furthermore facilitates the operation of the transformer and the power supply rectifier, as the current flow time through the rectifier gates increases. Apparatus of the Invention A device for smoothing pulsations of rectified voltage, comprising a choke connected between the input and output terminals, and two capacitors, one of which is connected in parallel to the output terminals, and the second one is connected to one of the input terminals, characterized in that in order to increase the efficiency, another output of the second capacitor is connected to another input terminal through a chain consisting of a counter-parallel-connected diode and a dynistor, with the polarity of switching on the last polarity in Suppressive voltage at the input pins. Sources of information taken into account in the examination 1. G. Weksler. Power supply of special equipment, Higher School, Kiev, 1975. 2. Weksler, S. S. et al. Transistor Smoothing Filters, “Technique, 1972. 3. Belopolsky I. I. Power Supply of Radio Devices, Gosenergoizdat, 1957, p. 213. + 0v -jzr , -0 Pus.i jtf 0 // 2 Uc.