SU851692A1 - Low-frequency ac voltage-to-dc voltage converter - Google Patents

Description

(54) AC VOLTAGE LOW FREQUENCY CONVERTER TO PERMANENT VOLTAGE

one

The invention relates to electrical engineering and can be used as a converter of low-voltage alternating voltage to direct voltage when constructing sources of various purposes.

AC / DC converters are known that contain a series-connected power transformer, a rectifier, a smoothing filter, and a regulating element 1 and 2.

The disadvantage of these devices is considerable weight and dimensions.

Closest to the proposed low-frequency AC / DC voltage converter, comprising an input rectifier and a conversion channel consisting of a high-frequency inverter connected in series with a power transformer, an output rectifier and a smoothing filter, as well as a control unit 3.

The drawbacks of the known device are the relatively low quality of mass-dimensional indicators and dynamic characteristics, since they depend on the degree of approximation of the envelope of the rectified voltage to the rectangular shape, which is defined as the number of taps of the primary winding of the power transformer (as well as key elements for their switching) and the duration of the front and rear fronts. In the ideal case, in a known transducer, a rectified voltage with an isosceles trapezoid shape can be obtained, the sides of which are sinusoidal segments. In the voltage spectrum of this form, low-frequency components are present with frequencies that are multiples of twice the input voltage frequency.

The purpose of the invention is to improve the mass and dimensional parameters and dynamic characteristics.

15 This goal is achieved by the fact that in a low-voltage alternating voltage-to-constant-voltage converter, containing an input rectifier and a conversion channel consisting of series-connected inverters,

Claims (3)

20 frequencies with a power transformer, an output rectifier and a smoothing filter, as well as a control unit, the conversion channel is connected to the input pins directly, and a booster channel consisting of an additional smoothing filter connected in series and controlled by an alternator is connected to the output of the rectifier. a voltage transformer, the secondary winding of which is connected in series, in the primary winding circuit of a power transformer of a high frequency inverter. FIG. 1 given electrical circuit of the converter; in fig. 2 - output voltages of its main blocks. A low-voltage AC / DC voltage converter contains an input rectifier 1 and a conversion channel consisting of a series-connected high frequency inverter on key elements 2-5 with a power transformer 6 and an output rectifier on diodes 7 with a smoothing filter on the choke 8 and a capacitor 9. The load 10 can be both active and reactive. In addition, there is a booster channel in the converter, by means of a smoothing filter 11 of which, the output of the input rectifier 1 is connected to a controlled generator on the key elements 12-15 with a voltage transformer 16. The control unit 17 serves to generate and distribute control signals to the key elements 2-5 and 12-15 either by the magnitude of the voltage on the load, or by commands from an external device. The Converter operates as follows. When voltage is applied at a frequency f to a high frequency inverter and alternately switching on elements 2.5 and 3.4 at the output of the inverter, we obtain a high frequency voltage f (Fig. 2). At the same time, the voltage is rectified by rectifier 1, smoothed by filter 11, and converted by the generator on elements 12-15 to square voltage U / rtj with the same frequency g. Three modes of operation are characteristic for the converter: booster, short-circuiting, and spinning. in the voltage boosting mode, by means of the transformer 6 and the transformer 16, the voltages Ut and are added together, and in the voltampump mode, they are subtracted. The short circuit mode, when the voltage of the secondary winding of the transformer 16 is O, is provided when elements 12, 14 or 13, 15 are turned on simultaneously. The switching algorithm of elements 12-15 for each of the modes is set by control unit 17. The rectified voltage Ug has the shape shown in FIG. 2, where a, b, and c are the modes of operation of the boost converter, short circuit and volt offset, respectively. Claims of the Inverter Low Voltage to Direct Current Voltage Converter Containing an Input Rectifier and a Conversion Channel Consisting of a High Frequency Inverter Series-Connected to a Power Transformer, an Output Rectifier and a Smoothing Filter, and a control unit characterized in that In order to improve the mass and size parameters and dynamic characteristics, the conversion channel is connected to the input terminals directly, and to the output of the rectifier is connected a booster channel consisting of an additional smoothing filter connected in series and a controlled generator with a voltage transformer, the secondary winding of which is connected in series to the primary winding circuit of a power transformer of an over-frequency inverter. Sources of information taken into account during the examination 1. USSR author's certificate No. 540336, cl. H 02 M 7/155, 1977. 2. The patent of Germany No. 2624532, cl. H 02 M 1/14, 1977. 3. USSR author's certificate Ho 505100, cl. H 02 M 5/12, 1976.