SU771780A2 - Controllable power-diode based generator - Google Patents

Description

one

The invention relates to power converter technology and can be used in ultrasonic process units.

According to the main author. St. 2400335

A generator is known on controlled valves, which contains a series circuit from a load and a filter capacitor, U

parallel to which single-phase bridge inverter cells are connected, each of which contains switching capacitors and chokes

1.15

The disadvantage of this device is that an increase in the limiting frequency of the output voltage is associated with the need to increase the number of inverter cells. This leads to a 20 "decrease in reliability.

The aim of the invention is to increase the frequency of the output voltage of the generator without increasing the number of inverter cells.

This is achieved by the fact that additional capacitors, which are interconnected by a star, are connected to the co-30 in the generator on controlled valves containing three cells, are introduced into the generator.

corresponding switching capacitors of the inverter cells and have a capacity that doubles the capacity of switching capacitors.

The drawing shows the scheme of the inverter.

The input terminals of the filter filter capacitor 2 and the load 3 are connected in series. . To the capacitors 28-30 of the inverter cells are connected star-connected additional capacitors 31-33, the capacity of which is twice the capacity of the capacitors 2830.

The device works as follows. At some point in time Vg, the control current pulses on thyristors 4 and 14, of the thyristors, are discontinued. The parameters of the cxeN elements are "chosen as

so that the thyristor current varies in time according to the oscillating law and reaches zero no later than 1/12 of the control voltage period (natural thyristor shutdown mode), after 1/12 of the control gain period after the VQ time, control current pulse. At the same time, a control current pulse is applied to the thyristor 7. As a result, the current loop formed by condenser 2, choke 16, thyristor 4, capacitor 28, drosel 19, thyristor 7, load 3 is released another 1/12 of the control voltage period a control current pulse is applied once. At the same time, a control current pulse is applied to the thyristor 10. The sequence of unlocking the thyristors within one control voltage period is shown in the table. There are also numbers of condensate and commuting chokes, through which the current circuit shuts down after unlocking the corresponding thyristors.

As follows from the table, in the intervals of simultaneous conduction of the valves of different cells, the current circuit is closed through two additional capacitors connected in series (31-33, or 31-32, or 33-32), while in the interval of conductivity of the valves only one cell is stored through a cell capacitor (28, 29.30). However, since the capacity of additional capacitors is twice the capacity of the capacitors of the inverter cells, the resulting capacitance of the current circuits in all the valve conduction intervals is the same. The inductance of the current circuits is also the same, and therefore all the input current pulses are inverter

0 cells are identical in shape and amplitude. One period of control voltage corresponds to 12 such pulses (see table).

The load current 3 according to the first Kirchhoff law is the difference between the current of the droplets 1 of the input filter and the input current of the inverter cells. The throttle current of the input filter is almost constant, and therefore the frequency of the load current (generator output frequency) is determined by the pulse frequency of the input current of the inverter cells, i.e. 12 times the control frequency

laziness. Accordingly, the duration of the load current period T is 1/12 of the control voltage period.

The time during which the voltage on the closed thyristors retains negative polarity (closure time) is not the same for the thyristors indicated in the diagram by even and odd numbers. Time

Claims (1)

Claim Generator on controlled valves, according to ed. St. No. 240033, characterized in that, in order to increase the frequency of the output voltage when using three inverter cells, it is equipped with three additional capacitors connected to a star and connected to the corresponding switching capacitors, and the capacity of the additional capacitors is twice the capacity of the switching capacitors.