FREQUENCY CHANGER

FIELD: electrical engineering; manufacture of converters and transformers. SUBSTANCE: frequency changer has transformer whose magnetic circuit is built up of N= 2k+1 cores, where k= 1,2,3... made of same magnetic material with rectangular hysteresis loop; each separate core carries different number of primary winding turns Wdifferentially connected in series, where k is core number, according to expression SW=SW, where Sis cross- sectional area of k-th core; Wis number of primary winding turns wound on k-th core. Each separate core also carries secondary winding turns Waccording to expression SW= SW,; each core, except for the last one, carries two isolating windings whose leads are connected through base resistors to emitter-base junctions of isolating transistors to form bidirectional switch which are interconnected so that emitter of each transistor is connected through diode anode-cathode to collector of other transistor and collectors of both transistors are connected to terminal leads of output winding of respective k+1 core. This provides for sequential polarity reversal of same-type cores both in open-circuit and loaded condition with preset sequence and for shaping voltage pulses across output windings equal in amplitude, opposite in polarity, and relatively shifted through angle Φ= K*π/N, where N is total number of cores in magnetic circuit; so, higher-frequency voltage is set up across changer output according to equation f= n*f,, where n = 2k+1, k = 1,2,3,...; fis output voltage frequency; fis input voltage frequency. In order to eliminate disturbance in polarity reversal and to raise loading capacity, as well as to improve output voltage characteristics, during polarity reversal of even-numbered core the next, odd-numbered, core does not reverse its polarity as its output winding is shorted out through conducting transistor of bidirectional switch. Enabling signal arrives at transistor from isolating winding wound on even-numbered core that reverses its polarity. Then odd-numbered core reverses its polarity and output of next, even-numbered, core is shorted out, etc. , until entire magnetic circuit reverses its polarity. This eliminates relative influence of polarity reversal of even- and odd-numbered cores. EFFECT: improved loading capacity of frequency changer and characteristics of its output voltage; simplified design; improved efficiency. 4 dwg Устройство относится к электротехнике, а именно к преобразовательной технике и к трансформаторо