SU1647704A1 - Method of communication of currents in phases of superconductor converter - Google Patents

Abstract

The invention relates to electrical engineering. The purpose of the invention is to improve the energy characteristics and quality of the voltage shape at the output of the superconducting converter. The superconducting converter using the method contains superconducting transformers 1-3 of phases A, B, C, cryotronic switches 5-7, a power supply and control unit 9 that regulates the amplitude, and a current sensor 10 that regulates the current in the load. The method allows, by eliminating pauses in the supply voltage, to increase the power of the superhigh-voltage transducer and, with an increased average voltage, linear current injection into the load while reducing the voltage ripple, thereby achieving the goal. 1 il.

Description

The invention relates to electrical engineering and can be used to power superconducting magnetic systems using superconducting (cryotronic) converters.

The aim of the invention is to improve the energy characteristics and quality of the output voltage.

The drawing shows a schematic diagram of a three-phase superconducting converter.

The superconducting converter contains superconducting transformers 1-3 of phases A, B, C, the first terminals of the secondary windings of which are combined and connected to the first terminal 4 for connecting the load, and the second terminals are connected via cryotronic switches 5-7 to the second terminal 8 for connecting the load. The keys 5-7 are controlled and the voltage supplied to the primary windings of superconducting transformers of each phase A, B, C is performed by the power and control unit 9, with the feedback output of which current sensor 10 is connected, which detects the current in the load.

The operation of a superconducting converter includes a strict sequence of processes that can be

consider as consecutive non-switching and switching intervals.

In each non-switching interval in one of the phases (for example, phase A) a load current of 1 H flows, and a voltage pulse with amplitude E acts in the primary winding of a superconducting transformer of this phase.

Before the start of switching, the cryotron keys 5 and b are switched to the open state in switched phases (for example, phases A and B) and the load current circulates in one of the phases (phase A), and the current in the other switched phase (phase C) equals zero.

The switching of phase currents is carried out by applying voltage pulses to the primary windings of superconducting transformers 1 and 2, switching phases (phases A and B) subject to the conditions

,, U5-2E Uki-

W + 2E

where Uid is the amplitude value of the voltage pulse to the primary winding of the semiconductor phase transformer with current (phase A);

Uk2 is the amplitude value of the voltage pulse on the primary winding of the superconducting transformer 2 phase without current (phase B);

E is the amplitude value of a voltage pulse acting in the primary windings of superconducting transformers 1.2 at non-switching intervals,

   and - the difference of the amplitude values of the voltage on the primary windings of the superconducting transformers 1 and 2 of the switched phases (A and B).

1H - load current;

This coefficient of proportionality is determined by the design of the superconducting converter and the winding parameters of superconducting transformers.

For the superconducting converter under consideration

... (1-k2) + and, h tk m

where tk is the duration of the switching interval;

Lp is the inductance of the primary winding of the superconducting transformer;

W is the mutual inductance of the windings of superconducting transformers;

K - transformation ratio;

LS is the inductance of the secondary winding of a superconducting transformer;

C - total inductance of additional elements (cryotronic valves

keys, busbars).

In this case, in a superconducting circuit formed by phases with public keys 5,6 (phases A and B), in the switching interval under the action of a voltage difference

 a circulating current ik IH is induced which compensates for the current in phase A to zero and induces a current of 1N in phase B.

To implement the switching modes, a sensor 10 is used, which performs

feedback of control unit 9 with load current 1H. In the switching interval of the remaining phases (in this example, phase C), the keys 5-7 are closed and the reverse voltage can be applied to them. In the considered switching interval, the voltage at the output of the converter is equal in magnitude and direction to the voltage that occurred on the extra-switching interval. At the end of the switching process in the phase,

in which the current is compensated to zero (phase A), the key resistance R is introduced (key 5 is turned off), and then the non-switching and switching processes are repeated in other phases.

Claims (1)

The invention method of switching currents in phases of a superconducting converter containing superconducting transformers according to the number of phases, the primary windings of which are connected to the output terminals of the power supply and control unit, with a feedback terminal connected to the load current sensor, and the secondary windings of superconducting transformers via cryotron switches , the control pins of which are connected to the control pins of the power supply and control unit are connected in parallel with each other and pins for connecting the load narrow, which means that during the switching time interval, with open cryotronic keys in switched phases and current flowing in one of these phases, a voltage pulse with a direction is applied to the primary windings of superconducting transformers of each phase opposite to the direction of the current flowing in the phase at the moment of time preceding the switching, characterized in that, in order to improve the energy characteristics and quality the forms of the output voltage, the magnitude of these pulses are determined by the ratio ,, Ш-2Е Uki Uk2 2 + 2E where Uici is the amplitude value of the voltage pulse on the primary winding of a superconducting phase transformer with current in the switching time interval; Uk2 is the amplitude value of the voltage pulse on the primary winding of a superconducting phase transformer without current in the switching time interval; 0 E is the amplitude value of the voltage pulse on the primary windings of superconducting transformers in the extra-switching interval;  Chn is the difference of the amplitude values of the voltage ne on the primary windings of superconducting transformers of the switched phases; 1n - current load; ui is the proportionality coefficient determined by the design of the superprojector converter and the winding parameters of superconducting transformers. 15