CS218622B1 - Inverting a reactive current commutating inverter with inductively coupled coils - Google Patents

Abstract

The invention relates to electrical engineering, specifically semiconductor inverters. The invention solves the problem of reactive current commutation of a resonant inverter using inductively coupled coils. The essence of the invention is the connection of commutation coils with a magnetically opposite inductive coupling, enabling the commutation of the reactive current of the diode to the relevant thyristor. The degree of coupling determines the exchange time of the current of the diodes and thyristors, as well as the magnitude of the output voltage in the steady state and the steepness of the increase in the current of the thyristors. The subject of the invention is the connection of a resonant inverter with reactive current commutation by inductively coupled coils, characterized by the fact that the load with a parallel connected commutation capacitor is connected to the positive pole of the source via a commutation coil and a thyristor with a zero diode connected in the opposite direction. Also, the negative pole of the power supply is connected to the load through the commutation coil and thyristors with a zero diode connected in the opposite direction. ' The opposite end of the load is connected to the middle . source outlet. Both commutating coils are placed on a common magnetic core and connected in opposite directions, as shown in Fig. 1 in the annex to the application of the invention.

Description

The invention relates to a resonant inverter with commutation of reactive current inductively coupled by coils.

So far, it is known to connect resonant inverters having magnetically matched coils used to commute an active line supplied from a unidirectional source to a load. If the resonant inverter is to be voltage-independent, it must contain a 'wrong rectifier' to return the reactive power of the load or commutation circuit to the unidirectional source. In this type of inverter, it is not possible to use magnetically coupled coils for commutation of the active current, since there would be no reactive energy return. The use of separate independent coils results in a large number of coils, large size, weight and increased inverter cost.

The above-mentioned drawbacks are eliminated by connecting the resonant inverter according to the invention, which is based on the connection of commutating coils with a magnetically opposite inductive coupling, enabling the reactive current of the diode to be switched to the respective thyristor, without disturbing the other operation of the inverter.

The incorporation of inductively coupled commutating coils allows for almost instantaneous, depending on the degree of inductive coupling, the exchange of diodes and thyristors. In addition, the inductive coupling allows both commutating coils to be placed on a common magnetic circuit, thereby substantially reducing the dimensions, weight and cost of the coils and the inverter. The utilization of the magnetic circuit to be used in both half-periods is also improved.

In the attached drawing of FIG. 1 is a circuit diagram of a resonant inverter with commutation of reactive current by inductively coupled coils. The above diagram is drawn by half-

Claims (3)

SUBJECT Connection of a resonant inverter with commutation of reactive current by inductively coupled coils, characterized in that a positive voltage is connected to the first common terminal of the load (8) and the parallel connected capacitor (7) via the coil (5) and the thyristor (1). (+) pole a via coil (6) and thyristor (2) with a counter-wiring with a medium source outlet. The analogous scheme applies to complete single-phase and three-phase connections. In FIG. 2 shows the time courses of thyristor current, diode, and output voltage during one steady state half-period. In the wiring of the resonant inverter according to FIG. 1, a load 8 with a parallel switched commutating capacitor 7 is connected to the positive pole of the source 9 via a commutation coil 5 and a thyristor 1 with a counter-connected zero diode 3. Also, the negative pole of the power supply is connected to the load 8 via a commutating coil 6 and a thyristor 2 with a reverse diode 4 connected. The other end, the terminal, of the load 8 is connected to the middle terminal 0 of the source 9. Both commutating coils are located on a common magnetic core and connected in the opposite direction. The inverter's steady state operation is as follows: Upon expiration of the active current half-period, given by the natural frequency of the resonant circuit formed by the commutating coil 5, respectively. by the coil 6, the commutating capacitor 7 and the load 8, the reactive current of the load 8, or the commutation circuit 7, are returned to the unidirectional source 9 by diode 3 in positive, and diode 4 in negative polarity of output voltage. After switching on the thyristors, which create another voltage half-period, the current is commuted from the positions of the leading elements: coils 5 resp. coils 6 and diodes 3, respectively. the diodes 4, the coil 6, or the non-conducting elements 6, respectively. coils 5 and thyristor 2, respectively. Thyristor 1, due to inductive coupling of coils 5 and 6. The degree of coupling determines the output voltage at steady state and also the steepness ´ of thyristor current increase 1 and 2. Possibility of using the invention is mainly in three-phase applications of resonant inverters, where the economic benefit will be greatest. BACKGROUND OF THE INVENTION diode (4) the negative (-) pole of the power supply (9), wherein the coils (5), (6) are disposed on a common magnetic core and connected upstream, and a second common load terminal (8) and parallel connected capacitor (7) it is connected to the middle terminal (0) of the power supply (9).