RU2539353C2 - Six-time magnetic semiconductor frequency multiplier - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: six-time magnetic semiconductor frequency multiplier is based on three-phase transformer and six double-winding saturable core reactors connected as per bridge circuit, which are coupled by the first diagonal line to secondary windings of the transformer and by the second wye-connected diagonal line to the load. Windings of one diagonal line for each saturable core reactor and load are shunted by single-period keys connected to the control unit through the key that shunts the load.

EFFECT: improved power parameters, widened range of output voltage symmetrical regulation at active and inductance load, reduced weight and dimensions.

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Description

The invention relates to the field of electrical engineering, in particular to converter technology, frequency multipliers, and can be used as power sources for high-speed engines, hand-held electric tools, for rectifiers, for regulated power sources of electrotechnological installations, for example, induction heating, etc.

Known magnetic semiconductor frequency multiplier adopted as an analogue (ed. Certificate. No. 497695, BI, No. 48, 1975), containing a multi-winding transformer with saturated cores, DC magnetizing windings and self-magnetizing windings with capacitors.

The disadvantages of the analog are: large mass and dimensions, inertia, the dependence of the amplitudes of the harmonics of the output frequency on the level of the bias current, low energy performance.

Known magnetic semiconductor frequency multiplier an even number of times, adopted as an analogue (ed. Certificate. No. 782084, BI, No. 43, 1980), containing a three-phase converter of the number of phases of double multiplication frequency and half-wave switches connected to the secondary windings of the aforementioned converter, and single phase transformer.

The disadvantages of the analogue are: large mass and dimensions, low energy performance due to the use of phase control of the keys along the switching angle, limited control range with active-inductive load.

Known magnetic semiconductor frequency multiplier, adopted as a prototype (ed. Certificate. No. 2323364, BI, No. 1, 1969, figure 2), containing a multi-winding transformer, to the secondary windings of which are connected the keys, inductors, the load installed between two stars , and a key management unit.

The disadvantages of the analog are: low overall dimensions, the dependence of the frequency settings on the parameters of the chokes, low reliability of the frequency multiplier.

The objective of the invention is: to increase energy performance, expand the range of regulation of the output voltage at an active inductive load, improve overall dimensions and simplify the design.

This goal is achieved by the fact that in a magnetic semiconductor frequency multiplier six times, containing a three-phase two-winding transformer and saturation chokes in each phase of the network, a load and half-wave keys controlled from the control unit, the windings of saturation chokes are connected according to a bridge circuit, one diagonals of which are connected to the secondary windings of the specified transformer, and the second diagonals are connected in two stars, between which the load is connected, and the windings of one diagonal of each saturation inductor Half-wave load shunted keys associated with the control unit via the key, shunt load.

The essence of the invention lies in the fact that the shunt key closes the winding of the saturation inductor at the beginning of the positive half-cycle for the time α π / 6, and from the moment of its opening, the core of the saturation inductor is magnetized and saturated at the moment β _k = 2π-α _k , which is uniquely associated with the angle switching regulatory keys, where α _k is the duration of the closed state of the regulatory key. A voltage is formed at the load, which is 6 times higher than the mains frequency, and all other harmonics below the sixth when added are mutually compensated. With an active-inductive load, from the moment α = α _{k the} control switch opens, the primary winding of the transformer is short-circuited with a zero key, ensuring current flow in the previous direction and free exchange of energy between the network and the load.

Figure 1 presents a diagram of a magnetic semiconductor frequency multiplier, and figure 2 is a timing diagram explaining the principle of its operation.

The magnetic semiconductor frequency multiplier 6 times contains a two-winding three-phase transformer 1, to the secondary windings 2, 3, 4 of which six saturable reactors 5-10 are connected with two windings 11-16, 11a-16a on each inductor, while the windings 11-16 and 11a-16a are connected by a bridge circuit. Some diagonals of the bridge are connected to the secondary windings 2, 3, 4 of the transformer 1, and the second are connected in two stars to the load 17. The windings 11-16 and load 17 are bridged with half-wave keys 18-24, which receive control signals from the control unit 25 through the key 24, installed parallel to the load 17 and acting as a zero valve to provide a discharge circuit of stored energy.

In Fig.1 shows a diagram of a frequency multiplier by 6 times, and Fig.2 is a timing diagram explaining the principle of operation at a switching angle α _k = π / 6.

At the beginning of the half-cycle from the control unit 25, a key 18 is closed, which shunts the winding 11 of the phase A voltage of the inductor 5 saturated in the previous half-cycle. A loop is formed: winding 2 - key 18 - load 17 - winding 11a of the inductor 1 - secondary winding 2, and is applied to the load 17 voltage segment 26 (figure 2, a). When the switching angle α = α _k = π / 6, the key 18 opens, and under the influence of the voltage of phase A, the saturation inductor 1 starts to magnetize and becomes saturated at the moment β _k = 2π-α _k . At the same time, under the influence of the phase C voltage, the inductor 10 is saturated, and after changing its polarity, the key 23 closes, while in the interval π / 6 α π / 2 the current flows through the circuit: first, winding 4 - winding 16a - load 17 - winding 16 and winding 4, and then 4-22-17-16a - phase 4, and voltage segments 27 and 28 of different polarity are formed on load 17 (Fig. 2, b). In the range of π / 2 α 5π / 6, phase B acts, first the inductor 7 is saturated, and then the key 20 shorts the winding 13. According to the contours: 3-13a-17-13-3, and then 3-20-17-13- 3, current flows and voltages 29 and 30 are applied to the load (FIG. 2, c). In the range of 5π / 6 α 7π / 6, phase A acts, with the first flowing current along the circuits: 2-12-17-12a-2, and after closing the key 19 along the circuit 2-19-17-12a-2, load formed voltage 31 and 32 (figure 2, g). Then phase C enters into action (Fig.2, d)). On the interval 7π / 6 α 3π / 2, the processes proceed in the inductor 9. It is saturated at first, and then the winding 15 is shunted by the key 22, and segments of sinusoids 33, 34 are applied to the load.

In the interval 3π / 2 α 11π / 6, phase B operates; first, the inductor 8 is saturated, and then the key 21 shorts the winding 14 of the inductor 8, forming a voltage of 35, 36 (Fig.2, e). In the last interval, at the moment β _k = 2π-α _{k, the} inductor 5 is saturated and the circuit flows: 2-11a-17-11-2, and a segment of sinusoid 37 is applied to the load 17. In the next voltage period, the processes are repeated.

Therefore, during the phase A voltage period, a common-mode voltage is applied to the load 17 with a frequency 6 times the frequency of the mains voltage.

When the active-inductive load 17 with the control angles α _k π / 6 from the moment of opening the control keys 18-23 from the key control unit 25, rectangular PWM pulses are sent to the key 24, which performs the functions of the zero valve, according to which on the interval α _k α β _k current flows in a short-circuited load circuit, decreasing exponentially. Key 24 operates at a frequency six times greater than control keys 18-23.

Magnetic materials with a narrow, rectangular hysteresis loop should be used for magnetic circuits of saturation chokes, and transistors should be used as keys: bipolar, such as IGBT, MOSFET or thyristors with capacitor switching, or GTO, IGCT and others.

Thus, in the proposed frequency multiplier, the output voltage is regulated 6 times over a wide range without shifting harmonics, regardless of the nature and parameters of the load, while the overall dimensions, reliability and energy indicators are increased. The inertia of the magnetic semiconductor regulatory body does not exceed a half-period of the network frequency.

Frequency multipliers of 6 times (300 Hz) can be made with a power of several hundred kilowatts.

Claims (1)

A six-fold magnetic semiconductor frequency multiplier containing a two-winding three-phase transformer and saturation chokes in each phase of the network, a load and half-wave keys controlled from the control unit, characterized in that the windings of the saturation chokes are connected by a bridge circuit, one diagonal of which is connected to the secondary windings transformer, and the second ones are connected in two stars, between which the load is connected, and the windings of one diagonal of each saturation inductor and the load are shunted half-time bubbled keys associated with the control unit via the key shunt load.

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