SU936290A1 - Ac-to-ac voltage converter - Google Patents

Description

The device relates to electrical engineering, in particular to converter equipment, and can be used in power supply systems of electrical and radio equipment,

Known AC voltage regulators are known in which the variation of the magnitude of the voltage across the load is made by switching transformer taps using controlled AC switches 1-5.

The drawback of such devices is high weight and size indicators, since in order to achieve high control accuracy, a large number of keys have to be introduced into the circuit, however, only two keys (thyristors) work in the device at the same time, and their continuous operation time is unlimited. In this case, it is necessary to calculate the heat sinks of each thyristor from the condition of transmission through this thyristor of the entire control power and the total area of the heat sinks is very large and often determines the weight and dimensions of the device.

The closest to the proposed is a variable

voltage to alternating, containing a matching transformer, the primary winding of which is connected to the input terminals, and booster transformer, the primary winding of which is made sectionalized, and the secondary winding is connected between the input and output terminals, and controlled AC switches,

10 connecting terminals of the secondary winding of the matching transformer with the terminals of the primary winding of booster transformer, every 1st tap of the secondary winding of the main

15 of the transformer, except for the latter, is connected via an appropriate controlled key with (1 + 1) -th tap, and its last tap is connected to the first tap of the booster transformer 20, respectively. The advantage of this device is the high efficiency of using key elements and the reduced installed capacity of transformer equipment 6.

However, the requirement of galvanic isolation of the keys among themselves leads to the fact that in this scheme, each thyristor in the key must be installed on its own heat sink i

oadator, not having electrical connections with other circuit elements. The overall dimensions of the device remain high. The installation of such devices is complicated, since the coolers must be installed inside the device case and must not have electrical contacts with the case and with each other. The likelihood of emergency operation due to possible short circuits between coolers due to installation errors or during operation reduces the reliability of the device. The use of symmetric thyristors as controllable keys does not lead to a gain in the mass of coolers, since in this case it is necessary to use heat sinks of twice the area and isolate them from each other and from the body of the device. Installing power semiconductor devices on a single radiator through insulating gaskets also does not give the desired effect, since this deteriorates heat removal from the thyristor, which causes the radiator to be too large and under-use thyristors in current. At the same time, the possibility of emergency mode arising due to the closure of two thyristors between each other, if the insulators are damaged, remains.

The aim of the invention is to reduce the weight and dimensions of the device, simplify installation and increase the reliability of the device.

The goal is achieved by the fact that in the device the matching transformer is made with m secondary windings, one of the outputs of each i-th secondary winding of the matching transformer is connected to the (1 + 1) output of the sectioned primary winding of the booster transformer the transformer and other terminals of the secondary windings of the matching transformer through controlled keys of alternating current, are connected to one point.

In this device, all controlled AC switches have a common connection point. In this case, using symmetric thyristors as controllable keys, it is possible to install all power semiconductor devices on one radiator without insulating gaskets, and choose the area of the radiator from the condition of simultaneous operation of two thyristors. The mass and dimensions of the cooler (and therefore the device) are significantly reduced, the installation of such a device is simplified, the reliability is increased.

The drawing shows a diagram of the device.

The device contains a matching transformer 1, having a primary winding 2, connected to an input terminal, and secondary windings 3-5 which have no direct galvanic connection between them, as well as a voltage transformer 6, the secondary winding 7 of which is connected between the input and output terminals, and The primary winding 8 is divided into several sections, the number of which is equal to the number of secondary windings of the matching transformer, and the controlled alternating current switches K fK ... , .K.One of the findings

each i-th secondary winding of the matching transformer is connected to the (i + l) -M output of the primary winding

booster transformer,

and the keys ICf, K2, ... .K | m connect the other

conclusions of the secondary windings of the main transformer and the first output of the primary winding of booster transformer at one point.

The regulation process proceeds in the same way as the well-known one: the closure of any two keys allows one voltage level to be formed at the load. Moreover, in this scheme, as well as in the well-known / it is possible to carry out both a voltage booster and a volt extraction.

Thus, in this device it is possible to significantly reduce weight and size indicators, simplify installation and increase reliability without introducing new elements into the elements and complicating the technology of winding an electromagnetic element.

Claims (6)

1. USSR author's certificate 401980, cl. G 05 P 1/20, 1973. 2. USSR author's certificate 478289, cl. G 05 R 1/28, 1975. 3. Authors certificate of the USSR 585487, cl. G 05 P 1/16, 1975, 4. Patent CU1A 3732485. class. G 05 P 1/30, 323-43,5, 1973. 5. US patent 3,732,486, cl. G 05 P 1/20, 323-13.5, 1973. 6. USSR Author's Certificate for Application No. 2886365 / 24-07, cl. H 02 M 5/257.