RU2307441C1 - Method for reducing dynamic losses in electric energy transformers - Google Patents

Abstract

FIELD: electric engineering, possible use in electric energy transformers, for example, in increasing and decreasing transformers.

SUBSTANCE: reduction of dynamic losses in suggested method occurs due to connection of device to transformer, which device ensures commutation of required keys of transformer at zero voltage, and at which commutation of all power keys and diodes occurs are zero current and (or) zero voltage. Suggested method may be realized by means of a device connected to the transformer. In parallel to required transformer key, to which other keys and transformer diodes may be connected in parallel, alternating-current wise, device input is connected. Device contains, in parallel to its input, a capacitor and a current impulse generator, consisting of serially connected inductive element, key with zero reverse conductivity and power buffer, and also contains device for draining energy from current impulse generator, for example, back into transformer.

EFFECT: reduced dynamic losses in electric energy transformers.

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Description

The invention relates to electrical engineering and can be used in electric power converters, for example in step-up and step-down converters.

There is a method of reducing dynamic losses when the key is turned on in a boost converter (power corrector) [1], which consists in limiting the recovery current of the converter diode, based on introducing into the converter circuit the diode of the converter in series with the inductive element, in parallel with which the diode and resistor are connected in series . The advantage of this method is the reduction of losses when turning on the converter key. The disadvantage is that losses remain when the converter key is turned off, and losses are added to the device resistor.

The closest analogue selected as a prototype [2] (Fig. 3) is a method of reducing losses in a boost converter (power corrector) using a device containing a capacitor connected to the converter, a current pulse generator containing an inductive element and a key with zero reverse conductivity, for example, a thyristor or a transistor and a diode connected in series, and a device for removing energy from a current pulse generator, which consists in turning off the diodes and the Browsers connected to each other in parallel with alternating current at zero voltage using a capacitor of a device connected in parallel with alternating current to said diodes and converter keys include the required of said converter keys at zero voltage by first resetting the voltage on said key by applying a current pulse between the terminals of the said key from the current pulse generator, include the key of the current pulse generator at zero current due to the presence of ind inactive element connected in series with the key of the current pulse generator.

The said device for implementing the indicated method is connected with its input parallel to the required converter key, to which other keys and converter diodes can be connected in parallel via alternating current.

An advantage of this method is the switching of diodes and converter keys at zero voltage.

The disadvantage is the presence of dynamic losses when the current pulse generator generator is not shunted by the capacitor when the current of the inductive element of the current pulse generator flows through it, more than the current of the converter key.

The technical result of the invention is to reduce dynamic losses in power converters.

The technical result of the proposed method is achieved in that they reduce losses in a device connected to a converter containing a capacitor, a current pulse generator containing an inductive element and a key with zero reverse conductivity connected in series, for example a thyristor or a transistor and a diode connected in series, and an energy removal device from the current pulse generator, due to the fact that you turn off the key of the current pulse generator at zero current by limiting the duration of the current pulse, you It is activated a current pulse generator, by the introduction of the current pulse generator of the energy buffer, such as a capacitor in series with said inductive element and key.

The invention is illustrated by drawings.

Figure 1 presents part of the structural power circuit of the Converter and the structural power circuit of the inventive device.

In Fig.2 presents plots of voltages and currents explaining the operation of the circuit shown in Fig.1.

Figure 3 presents part of the structural power circuit of the Converter and the structural power circuit of the prototype device [2].

The proposed method can be implemented using connected to the Converter 1 device 1, shown in Fig.1. Parallel to the required key 3 of converter 1, to which other keys and diodes 4 of converter 1 can be connected in parallel via alternating current (here, circuit 5 circuits the levels of constant potentials), the input of device 2 is connected. Device 2 contains a capacitor 6 and a current pulse generator in parallel with its input 7, consisting of a series-connected inductive element 8, a key with zero reverse conductivity 9 and an energy buffer 10, and also contains a device for removing energy 11 from the current pulse generator 7, example, back to converter 1.

The operation of the device is as follows (Fig.1 and 2). Upon the arrival of the control signal at time t ₁ about the need to zero the voltage on the required key 3, turn on the key 9. The latter is turned on at zero current, that is, with low losses, due to the presence of inductive element 8 connected in series with it. As the current increases along the generator circuit of current pulses 7, the voltage decreases on the required key 3, which leads to a change in the sign of the voltage on the inductive element 8 at the time of the maximum current of the inductive element 8, as well as to zero the voltage on the required key 3 at the moment t ₂ - at this moment the key 3 is turned on with low losses. After changing the sign of the voltage on the inductive element 8, the current through the last, and therefore through the switch 9 starts to decrease and becomes equal to zero at time t ₃ . Further, the reverse current in the inductive element 8 does not occur (up to the imperfect properties of the key 9) due to the zero reverse conductivity of the key 9. At time t _{3, the} key 9 is turned off with low losses.

When the above process occurs, a certain energy is transferred to the energy buffer. The output of this energy, for example, back to the converter 1 is carried out by the energy removal device 11, for example, a recovery device.

Further, at time t _4, switch 3 is turned off and the voltage at the latter rises in a time longer than the closing time of switch 3, due to the presence of a capacitor 6 connected in parallel to the latter. This ensures low losses when switching off switch 3, that is, switching off at zero voltage.

At time t _{5, the} process repeats again.

If, as part of the energy buffer 10, a matching or isolation transformer is used at its input, then the transformer inductance is used as the inductive element 8.

An analysis of the known technical solutions showed that the proposed method of reducing dynamic losses in electric power converters exhibits new properties, which include reducing dynamic losses in electric power converters.

Information sources

1. Bonomorsky P. et al. Base unit of a power supply with power factor correction for a PC // Electronic Components, 2002, No. 8, pp. 107-110.

2. W.A. Tabisz and F.C. Lee, "Zero-voltage switching multi-resonant technique - a novel approach to impruve performance of high frequency quasi-resonant converters", IEEE Power Electronics Specialists Conference, 1988.

Claims (1)

A method of reducing dynamic losses in power converters using a device containing a capacitor connected to the converter, a current pulse generator containing a series-connected inductive element and a key with zero reverse conductivity, and a device for removing energy from the current pulse generator, which consists in turning off the required keys and the diodes of the converter, connected together in parallel by alternating current, at zero voltage using the capacitor of the device, is connected parallel in alternating current to the said keys and diodes of the converter, include the required of the said converter keys at zero voltage by first zeroing the voltage on the key by applying a current pulse between the terminals of the key from the current pulse generator, include the key of the current pulse generator at zero current for due to the presence of an inductive element connected in series with the current pulse generator key, characterized in that the pulse of the generator key is turned off a current at zero current by limiting the current pulse generated by the pulse current generator, by introducing into the energy buffer generator current pulses to said series inductive element and key.

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