SU696586A1 - Transistorized inverter with pulse-width modulation - Google Patents

Description

The invention relates to a converter technique, to converters made on semiconductor devices with a control electrode, and can be used in secondary power supplies of electronic equipment in controlled electric drives and in automation. A power source is implemented on two transistor inverters assembled on a push-pull circuit with self-excitation 1. One of the inverters is synchronized by the voltage of the other inverter by turning on the synchronizing winding in the base circuits of its transistors, and the output voltage of the auxiliary inverter is controlled by changing This is the time of recharging of the condenser connected via the control resistor to the base windings of the output transformer in the synchronous winding circuit. A disadvantage of this device is its complexity, due to the use of three additional polarity groups of diodes, providing a process of overcharging and a capacitor, as well as a low efficiency due to the additional losses from through-currents. A well-known inverter is known that allows pulse-width modulation by adjusting the output voltage, while this inverter operates at high frequencies and does not have through-currents 2. The drawback of the device is the small modulation range of the output voltage frequencies. The disadvantage is due to the fact that with an increase in the delay time, the duration of the saturating transistor pulse decreases with the exponential law of charge buildup leads to a decrease in the degree of saturation of the transistor and limits the increase in the delay. The closest in technical essence is a transistor inverter with a latitude-ravI pulley modulation, containing a square voltage generator and a driven push-pull generator with output transformers, the output windings of which are connected in series, and each synchronizing winding of the square voltage generator is connected to a control the transition of the corresponding transistor of the slave generator through the base winding of this generator and the common regulating element and reactive element | 3 |, However, this inverter only allows a wide range of modulation at low frequencies of the order of tens and hundreds of hertz. When using such inverters, the problem of producing rectified voltage arises. Therefore, in this case, it is advisable to use such inverters at high frequencies, since in this case the size of the output transformers is reduced.

The aim of the invention is to ensure the operation of the inverter at high frequencies.

This is achieved by the fact that the proposed transistor inverter contains a rectangular voltage generator and a driven push-pull generator with output transformers, the output windings of which are connected in series, and the synchronizing winding of the rectangular voltage generator connected to the corresponding transistor of the slave generator through The base winding of this generator and the common regulating element and the reactive element, which is connected with the control element, form a corrective yu chain. In this case, the reactive element can be either in the form of a capacitor connected in parallel to the control element or in the form of a transformer through the primary half windings of which the synchronizing windings are connected to the control transitions of the transistors of the driven auto-generator, and the control element is included in the secondary winding of this transformer.

The presence of a correction circuit allows you to change the shape of the base current of the transistors so that, depending on the type of reactive element, a more rapid establishment of an excess charge in the base with the accumulation of a scientific research institute of reactive energy by the element, or less intense absorption of the accumulated charge occurs when the reactive energy is consumed an item. In the first case, the reactive element allows to force the saturation of the transistor, in the second case it absorbs the resorption process.

Consistently turning on the load windings of the output transformers leads to a decrease in the collector current of the switched-off transistor in the delay interval and a decrease in the magnitude of the saturation boundary charge, so

As with such switching on of the load windings, the current in the load does not flow over the delay interval. The control of the delay occurs in the idling mode of the slave oscillator, which, with the same parameters of the control signals, makes the circuit more sensitive to the control action.

Fig, 1, schematically shows the proposed inverter:

1 — rectangular voltage generator, 2 — driven two-clock auto-generator, 3,4 — output transformers of the rectangular-voltage generator and driven auto-generator, 5.6 — basic windings of the output transformer of the driven auto-generator, 7.8 — synchronizing windings of the driven auto-generator, 9 , 10 — the transistors of the slave auto-generator, 11, 12 — the output windings of the transformers 13 — the load, 14 — the control element, 15 — the capacitor.

Claims (3)

The operation of the inverter is carried out in accordance with the time diagrams (Fig. 2). The rectangular voltage source 1 generates a variable rectangular voltage V. The voltage removed from the winding 11 and synchronizing windings 7.8, From the synchronizing windings, the voltage is applied to the base junctions of the transistor 9, 10 of the slave oscillator, performing its synchronization, W) 1 the voltage of the oscillator 2, removed from the winding 12 V, and the base windings 5,6 repeats the shape of the voltage of the source 1, but is phase shifted to the rear of the switching transistors 9, 10. The total voltage is a sequence of variable width modulated pulses, the duration of which depends on the time of the rtepe1 switching of the transistors 9, 10, associated with the time of dissipation of excess charge in the base of saturated transistors. The current in the load 13 and in the collector circuits of the transistors 9, 10 with the agreed connection of the windings 11, 12 flows only at the coincidence intervals 56 of the polarity of the source i and the oscillator 2. In the delay interval of the output voltage of the autogenerator 2 there is no current in the load, and the collector current of the transistors 9, 10 decreases to the value of the no-load current of the transformer 4. Accordingly, the magnitude of the boundary charge of the base decreases and the excess charge of the minority carriers of the base of the open transistor increases. Thus, the formation of the delay is carried out at small values of the boundary charge, which allows increasing the sensitivity of the circuit and eliminating the influence of the load on the modulation process. The switching delay of the transistors is controlled by adjusting the saturation and resorption modes of the base of the open transistor. The control voltage of the transistors 9, 1O, spimen from the windings 5, 7 and 6, 8, respectively, repeats in the form of a voltage, but has a smaller amplitude. Consider the processes in the circuit, starting from the moment of unlocking the transistor 9.. The uncoupling voltage of the windings 5.7 leads to the forced saturation of the transistor with a capacitor current and the rapid establishment of an excess charge Qg The established value of the excess charge is determined by the active component of the base current flowing through resistor 14. With the change in polarity of the synchronization voltage V, the process of dissolving the excess charge under the action of the voltage difference across the windings of 5.7, the energy stored by the capacitor and carrier recombination in the bulk of the base. When the charge value reaches a transistor, the transistor 9 goes out of saturation and closes, which leads to a change in the polarity of the output voltage of the autogenerator 2 and the optics of the aransistor 10. In the future, the processes are periodically repeated. The ramping down of the modulation range occurs due to the forced saturation of the transistors of the slave oscillator with the capacitor charge current and the exclusion of the dependence of the excess charge on the duration of the saturating pulse. The sensitivity with the windings in the load circuit is consistent as a result of the decrease in the collector current of the open transistor in the delay interval, which leads to an abrupt increase in the excess charge due to a decrease in the boundary value of the saturation charge. FIG. 3 is a schematic diagram of an inverter in which the inductance of the magnetizing circuit of the transformer 16t 17, 18 primary transformer 17, 18 19 secondary windings of the transformer 19 are used for extending the range of the transformer 16t. Synchronous windings 7.8 of the slave autogenerator 2 are connected to a common transistor bus 9 , 10 through the primary half windings 17, 19 of the transformer 16. The control element 14 is included in the secondary winding circuit 19 of the transformer 16. The operation of this device is characterized in that the unlocking of the transistor forsiruets and rasshireyute modulation range is due to retard resorption process accumulated excess zar5zda by changing the polarity of the synchronizing voltage zhe1sh. The current in the base of the open transistor does not change its sign, but flows in the same direction, decreasing according to the law of current decay in the inductance, and supports an excess charge decreasing due to recombination. The device can be performed on a two-stroke autogenerator assembled along a beam, bridge, and known circuits, both single-phase and multiphase. Claim 1. Transistor inverter with pulse-width modulation, containing a rectangular voltage generator and a driven push-pull generator with output transformers, the output windings of which are connected in series, and each synchronous winding generator of a rectangular voltage generator is associated with a control transition of the corresponding driven transistor a generator through the base winding of this generator and a common regulating element, And a reactive element, characterized in that, in order to ensure s of the inverter at higher frequencies, the reactive element is coupled to the control member forming the correcting circuit, the inverter 2. Transistor according to claim 1, distinguished ayuschiys in that the reactive element is a capacitor connected in parallel sound control &. l yushemu element. 3. Transistor inverter according to claim 1, characterized in that the reactive element is designed as a transformer, through the primary semi-windings of which the synchronizing windings are connected to the control transitions of the slave auto-oscillator transistors, and the control element is connected to the secondary winding of this transformer . 696586 yu number yo cl. 8 Sources of information taken into account during the examination 1. Patent U.S.S. No. 3031629, Ya. 31-11U 1962. 2. USSR author's certificate 545О54, cl. H 02 M 7/537; 1974. 3. Authors certificate of the USSR and Vk № 2519407/07, H 02 M 7/537, 1977. FIG.