RU2007829C1 - Alternating-to-direct voltage converter - Google Patents

Abstract

FIELD: electric engineering. SUBSTANCE: device has transformer 1, rectifier 2, which input terminals are connected to terminals of secondary winding of transformer, capacitor 3 and loading 4 which are connected in parallel to joint between output terminal of rectifier and tap of middle point of transformer secondary winding. In addition device has two MOSFETs 5, 6 having n-channel, two MOSFETs 7, 8 having p-channel, two diodes 9, 10. Cathode of diode 9 is connected to anode of diode 10 and to second terminal of input power supply which first terminal is connected to first output terminal of primary winding of transformer. Second output terminal of primary winding of transformer is connected to discharging output of first MOSFET having n-channel and to first MOSFET having p-channel which charging input and substrate are connected to cathode of second diode and to charging input and substrate of second MOSFET having p-channel. Discharging output of the latter MOSFET is connected to discharging output of second MOSFET having n-channel which charging input and substrate are connected to anode of first diode and to charging input and substrate of first MOSFET having n-channel. Gate of this MOSFET is connected to gate of first MOSFET having p-channel. Gate of second MOSFET having n-channel is connected to gate of second MOSFET having p-channel. Use of transformer is improved by full demagnetizing or re-magnetizing of its core due to introduced primary winding coils which form additional section which first terminal is connected to first terminal of primary winding of transformer and which second terminal is connected to discharging output of second MOSFET which gate is connected to second control terminal. First control terminal is connected to gate of first MOSFET. EFFECT: improved use of transformer. 2 dwg

Description

 The invention relates to electrical engineering, radio electronics and is intended for use in converting devices as a secondary power source with a capacitive storage for pulsed load (for example, gas discharge).

 Widely known voltage converters, which are chargers with various current-forming elements [1]. The input voltage in them is a constant voltage, which is converted by an inverter into an alternating voltage. Then this alternating voltage is rectified and charges the capacitive storage. Between the inverter and the rectifier, matching elements can be included or a direct connection is used between them. Capacitive storage can be directly connected to the output of the rectifier or through a matching element. If an alternating voltage is used as the input voltage, an additional rectifier and a smoothing filter must be used. This, of course, will lead to a decrease in efficiency and worsen overall dimensions, which is a drawback of analogues.

 As a prototype, an AC to DC converter [2] was selected, containing a transformer, a rectifier, the input terminals of which are connected to the extreme terminals of the transformer secondary winding, a capacitor and a load connected in parallel and connected between the output terminal of the rectifier and the output from the midpoint of the secondary transformer winding, two MOS transistors with an n-channel, two MIS transistors with a p-channel and two diodes, the anode of the first of which is connected to the sources and substrates of both MIS transistors with an n-channel, the drain and which are connected to the second terminal of the primary winding of the transformer and the drains of both MOS transistors with a p-channel, the sources and substrates of which are connected to the cathode of the second diode, the anode of which is connected to the cathode of the first diode and the second terminal of the input voltage source, the first terminal of which is connected to the first the output of the primary winding of the transformer, and the output of the control circuit is connected to the gates of all four MOS transistors. Such a converter allows the core of the transformer to be completely remagnetized only when the next half-wave (low-frequency) input voltage arrives at its input. The work of the prototype with a long magnetized core leads to the need to increase the dimensions and mass of the transformer, to reduce the output power and efficiency of the converter.

 The objective of this invention is the improvement of the use of the transformer: this achieves the required technical result due to its complete demagnetization (magnetization reversal) when switching the MOS transistors in the AC to DC converter containing a transformer, a rectifier, the input terminals of which are connected to the extreme terminals of the transformer secondary winding, capacitor and load connected in parallel and connected between the output terminal of the rectifier and the terminal from the midpoint of the secondary winding transformer, two MOSFET transistors with n-channel, two MOSFETs with p-channel and two diodes, the cathode of the first of which is connected to the anode of the second diode and the second terminal of the power source, the first terminal of which is connected to the first terminal of the primary winding of the transformer, the second the output of which is connected to the drains of the first MOSFET transistor with an n-channel and the first MOSFET transistor with a p-channel, the source and substrate of which are connected to the cathode of the second diode and the source with the substrate of the second MOSFET transistor with a p-channel, the drain of which is connected to the drain second TIR-t a transistor with an n-channel, the source and substrate of which is connected to the anode of the first diode and the source with the substrate of the first MOS transistor with an n-channel, the gate of which is connected to the gate of the first MOS transistor with a p-channel, and the gate of the second MIS transistor with n -channel is connected to the gate of the second MIS transistor with a p-channel, distinctive features from the prototype are that the primary winding of the transformer is supplemented with turns forming its additional section, connected by its own output to the first output of the primary winding of the transformer pa, and its second output - to a drain of the second MIS transistor whose gate is connected to the second control terminal, a first terminal connected to the control gate of the first MIS transistor.

With a positive half-wave of the input voltage U _in , the device is operated using MIS transistors with an n-channel, and with a negative half-wave of U _in - using MIS transistors with a p-channel. Since MIS transistors with an n-channel with a positive half-wave U _in (and also MOS transistors with a p-channel with a negative half-wave U _in ) open and close alternately, the current in the primary (and secondary) winding of the transformer will flow in one, then in another (opposite) direction (for any polarity U _in ). As a result, the core of the transformer will be completely remagnetized, i.e., there will be no permanent magnetization in it.

 In FIG. 1 is a schematic diagram of an AC to DC converter; in FIG. 2 is a timing diagram of the current in the transformer windings.

The proposed AC to DC converter contains a transformer 1, a rectifier 2, a capacitor 3, a load 4, two MOS transistors with an n-channel 5 and 6, two MOS transistors with a p-channel 7 and 8, two diodes 9 and 10. The transformer 1 has two windings: primary and secondary. The extreme terminals of the secondary winding of the transformer 1 are connected to the input terminals of the rectifier 2, between the output terminal of which and the output from the midpoint of the secondary winding of the transformer 1, capacitor 3 and load 4 are connected in parallel to each other. The first terminal of the input voltage source is connected to the first terminal (middle point) of the primary windings of transformer 1, the second (extreme) terminal of which is connected to the drains of the MOS transistors 5 and 7. The third (extreme) terminal of the primary winding of transformer 1 (from the extreme turn of the additional section) connected to the drains of the MOS transistors 6 and 8. The sources and substrates of the MOS transistors 5 and 6 are connected to the anode of the diode 9, and the sources and substrate of the MOS transistors 7 and 8 are connected to the cathode of the diode 10. The cathode of the diode 9 and the anode of the diode 10 are connected to the second terminal of the power source. The gates of the MOS transistors 5 and 7 are connected to the first control terminal, and the gates of the MOS transistors 6 and 8 are connected to the second control terminal. The rectifier 2 can be made as in analogues, as in the prototype or otherwise. Capacitor 3 performs the function of energy storage. As the load 4 can be used various devices and elements (laser, gas discharge lamps, etc.). The control signals U _control1 and U _control2 must be bipolar. When U _CP1 has a positive polarity, U _CP2 is negative, and vice versa. The duration of the control pulses depends on the specific technical requirements, and their frequency should be much greater than the frequency of the input voltage.

 The proposed device operates as follows.

With a positive half-wave of the input voltage U _{I, the} current flow in the primary winding of the transformer 1 is determined by the open state of the MOS transistors 5 and 6, since the diode 9 is turned on in the through direction. At a negative half-wave U _{in, the} current flow is determined by the open state of the MOS transistors 7 and 8, since in this case the diode 10 is already turned on in the through direction. To open the MOS transistors 5 and 6, positive pulses are received at their gates, and to open the MIS transistors 7 and 8, negative pulses are received. Since the frequency of the unlocking pulses U _{control 1} and U _{control 2} will be significantly higher than the frequency U _I , then for one half-wave of the input voltage, the current in the windings of the transformer 1 will repeatedly change its direction of flow (see Fig. 2). So, when the MOS transistor 5 (or MIS transistor 7) is open, the current will flow through the first (main, left) section of the primary winding of the transformer 1 through the MIS transistor 5 (or 7) and diode 9 (or 10). When the MOS transistor 6 (or MIS transistor 8) is open, the current from the input voltage source will flow through the second (additional, right) section of the primary winding of the transformer 1 via the MIS transistor 6 (or 8) and diode 9 (or 10).

 The signals from the secondary winding of the transformer 1 are converted by the rectifier 2 into a pulsating unipolar voltage supplied to the capacitive energy storage 3. When the load 4 is connected (ignited), the capacitor 3 is discharged to the load 4.

 Due to the change in the direction of current flow in the windings of the transformer 1, the magnetization of the core of the transformer is completely reversed, that is, its permanent magnetization is absent. This circumstance improves the use of transformer 1, allows to reduce its dimensions and weight.

 An experimental check of the AC to DC converter was carried out on MIS transistors KP701, KP702, 2P703, 2P803 and laboratory samples.

 In the proposed device was observed multiple full magnetization reversal of the transformer magnetic circuit during the action of one half-wave of the input voltage. (56) 1. Bulatov O.G. et al. “Semiconductor Chargers of Capacitive Energy Storage”, M., “Radio and Communication”, 1986, p. 43.

 2. Copyright certificate of the USSR N 1693701, cl. H 02 M 7/217, 1971.

Claims (1)

 AC VOLTAGE CONVERTER TO CONSTANT, containing a transformer, the first terminal of the primary winding of which is connected to the first of the input terminals for connecting the power source, and its secondary winding is connected to the input of the rectifier, the output of which forms output terminals for connecting the load, between which the capacitor is connected, two MIS a transistor with an n-channel, two MIS transistors with a p-channel, two diodes, the cathode of the first of which is connected to the anode of the second diode and the second input terminal, as well as two control outputs for connecting the corresponding outputs of the control unit, the second terminal of the primary winding of the transformer connected to the drains of the first MOSFET transistor with an n-channel and the first MOSFET transistor with a p-channel, the source and substrate of which are connected to the cathode of the second diode and the source with the substrate of the second MOSFET with a p-channel, the drain of which is connected to the drain of the second MOS transistor with an n-channel, the source and substrate of which are connected to the anode of the first diode and the source with the substrate of the first MOS transistor and with an n-channel, the gate of which is connected to the gate the first MOSFET transistor with a p-channel, and the gate of the second MOSFET transistor with an n-channel is connected to the gate of the second MOSFET transistor with a p-channel, characterized in that the primary winding of the transformer is additionally equipped with turns forming an additional section connected with one of its output to the first terminal of the primary winding of the transformer, and its second terminal to the drain of the second MOS transistor, the gate of which forms the second control terminal, and the first control terminal is formed by the gate of the first MOS transistor.

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