RU2231901C2 - Method and device for regulating voltage of any kind - Google Patents

Abstract

FIELD: secondary power supply systems.

SUBSTANCE: proposed method and device that can be used for instance in ac sine-wave, ac asymmetric, rectified, and dc voltage regulators and stabilizers, in power modulators of automatic-control systems and radio equipment, low- and high-voltage drives depend for their operation on conversion of rectified output voltage into high-frequency uniformly pulse-width modulated voltage in response to voltage increase in step with input voltage rectification, its addition to input voltage, and output filtration; input voltage reduction is effected by its uniform pulse-width modulation followed by output filtration.

EFFECT: enhanced power characteristics.

3 cl, 3 dwg

Description

The invention relates to a conversion technique and can be used in secondary power supply systems, in particular in regulators and stabilizers of an alternating sinusoidal, alternating asymmetric, rectified and constant voltage.

A known method of discrete voltage regulation [1], which consists in the implementation of discrete regulation of the current input voltage level, based on comparing the latter with the current values of two specially formed voltage levels and using the comparison result as control coefficient information of the regulatory body.

The disadvantages of this method are:

- distortion of the shape of the output voltage under the influence of destabilizing factors both from the supply network and from the load side, expressed in limiting the output voltage to instantaneous values;

- limited accuracy of regulation of the output voltage at the level of discreteness of the regulatory body.

Closest to the proposed invention (prototype) is a method for regulating AC voltage [2], based on high-frequency alternation of the shunt mode of the boost transformer with the mode of voltage addition or voltage subtraction and change of duty cycle during the mixed switching of keys.

The disadvantages of this method are:

- additional losses in power switches in the bypass mode of a boost transformer;

- low quality of the output voltage (increased level of high-frequency harmonics), especially at the beginning and end of the input voltage range, since the switching frequency of power switches cannot exceed several hundred hertz.

This is due to the fact that the magnetization of the core of the magnetic circuit when switching power switches has one sign and is carried out within the half-cycle of the mains voltage, therefore, the transformer must be designed for the main frequency of the mains voltage. In addition, it is necessary to take into account the magnetization of the magnetic circuit of the transformer by the load current. An increase in the switching frequency of power switches will lead to additional losses in the magnetic circuit (loss of magnetization reversal) and in copper (due to the skin effect), since the length of the wires in the windings will correspond to the parameters of the low-frequency transformer.

Known AC voltage stabilizer [3], containing a transformer connected by a secondary winding to one of the power buses, primary, through switching elements connected to the input voltage, a comparison and control device, switching elements are connected in such a way that depending on the output voltage determined by the circuit comparison and control, and the level control circuit, the primary winding is connected so that the voltage on it changes polarity, or the transformer operates in the current transformer mode short-circuited primary winding and through the power switch, the control circuit which is connected to a comparison and control circuit and the first bridge circuit output voltage is maintained with a certain degree of accuracy.

The disadvantages of this AC voltage stabilizer are

- limited by the transformation ratio of the transformer, the accuracy of stabilization of the output voltage;

- additional losses in the power elements of the shorted primary winding of the transformer in the current transformer mode.

Closest to the proposed invention (prototype) is an electronic voltage stabilizer [4], which contains a boost booster transformer, a reversing bridge, a regulating key of two counter-parallel connected transistors, a current sensor, shunt transistors, a pulse-width modulator, and logic circuits.

The disadvantages of this electronic voltage stabilizer are:

- additional losses in power switches in the bypass mode of a boost transformer;

- the increased switching frequency of the control key does not lead to a decrease in the size of the boost booster transformer, since the magnetization of the magnetic circuit during switching of the control key has one sign and is carried out within the half-cycle of the mains voltage in the presence of magnetization by the load current, therefore, the transformer must be made from the operating condition at the mains frequency ; Thus, the low-frequency transformer must satisfy the requirements of the high-frequency transformer (losses in the magnetic core due to magnetization reversal and losses in copper due to the skin effect) with the dimensions of the low-frequency; reduction of losses in the magnetic circuit will require the implementation of the core of the transformer from high-frequency materials (ferrite, amorphous alloys); but magnetic cores made of high-frequency materials have a lower induction compared to low-frequency electrical steel, which will lead to an increase in the number of turns in the windings of the boost transformer and, consequently, to an increase in losses in the transformer windings;

- it is impossible to regulate and stabilize a voltage of a different kind than sinusoidal.

The invention is aimed at solving the problem of regulation and stabilization of voltage of any kind.

The technical result of the invention is to expand the functionality, increase energy performance, improve the quality of the output voltage and regulation, reduce weight and dimensions.

The problem is solved using a method of regulating any type of voltage, based on the voltage addition of high-frequency voltage with increasing voltage, and the input voltage is pre-rectified, converted into high-frequency AC with amplitude and pulse-width modulation (PWM), transformed, rectified synchronously with the input, summed with input and smooth at the output, and lowering the input voltage is carried out using pulse-width modulation and smooth at the output.

A method of controlling voltage of any kind is implemented using a voltage regulating device of any kind containing a transformer, a control key, a current sensor, a second control key, a rectifier is connected to the input of the device, the output of which is connected to the power bus of the high-frequency converter, the control inputs of which are connected to the control unit, and the output of the rectifier to the primary winding of the transformer, the secondary winding of which is connected by the midpoint to the input voltage phase wire, and the other two and conclusions to the inputs of rectifiers of positive and negative polarities, the outputs of which are connected through a regulating switch to a smoothing filter and the first output of an electronic key with controlled conductivity, the second terminal of which is connected to a neutral wire, and the control inputs of an electronic key with controlled conductivity to a control unit, the output is smoothing the filter through the current sensor is connected to the output of the device and through the feedback circuit with the control unit, the other two inputs of which are connected to the phase wire and the outputs dy current sensor, and the key regulatory control inputs to the control unit and the control unit is a microcontroller, and incorporates a program control unit, the pulse width modulator and the analog-to-digital converter.

A block diagram of a voltage regulating device of any kind is shown in Fig. 1, and timing diagrams of voltages explaining the operation of the device using the example of regulating a sinusoidal voltage in the voltage boost mode - Fig. 2, and in the lower mode - Fig. 3.

A voltage control device of any kind (Fig. 1) contains a rectifier 1, the output of which is connected to a high-frequency converter 2, the control inputs of which are connected to the control unit 3, and the output to the primary winding of the transformer 4, the secondary winding of which is connected with the midpoint to the “Phase” wire input voltage, and the other two outputs to the inputs of rectifiers of positive and negative polarities 5 and 6, respectively, the outputs of which are connected via control keys 7 and 8 to the first output of the electronic circuit yucha with controlled conductivity 9 and a smoothing filter 10, the second output of the electronic key with controlled conductivity 9 is connected to the wire “0”, and the control inputs of the electronic key with controlled conductivity 9 to the control unit 3, the output of the smoothing filter 10 through the current sensor 11 is connected to the output device and through the feedback circuit to the input of the control unit 3, the other two inputs of which are connected to the wire “Phase” of the output voltage Uout and the output of the current sensor 11, and the two outputs of the control unit 3 are connected to the control keys 7 and 8.

Consider a method of regulating voltage of any kind, implemented using a device using the example of regulating sinusoidal voltage.

The input voltage is supplied to the input of the rectifier 1, the input of the control unit 3, which is a microcontroller (incorporating a program control unit, pulse-width modulators and an analog-to-digital converter) and to the midpoint of the transformer 4, and the input of the control unit 3 and the middle output transformer 4 connected to the wire "Phase". If the network voltage is less than the specified output (Uout) (Fig. 2, a), the control unit 3 generates PWM modulated control pulses of the high-frequency converter 2. From the output of the converter 2, the high-frequency voltage is alternating with amplitude and pulse-width modulation (Fig. 2, b ) is supplied to transformer 4. From the secondary winding of transformer 4, voltage is supplied to two rectifiers 5 and 6, for converting it into unipolar - positive and negative polarities, respectively. With a positive half-wave of voltage at the input, the control unit 3 turns on the control key 7 (Fig.2, c), and with a negative one - the control key 8 (Fig.2, d). The synchronization of the operation of the control keys 7 and 8 with the network is carried out by the control unit 3, where the moments of transition of the input voltage through zero are determined by software. The transformer 4 is included in relation to the network as a boost, therefore, the voltage at the output of the control switches 7 and 8 is the sum of the mains voltage and the voltage at the output of the transformer 4 (Fig.2, d). From the output of the control keys 7 and 8, the voltage thus formed through the smoothing filter 10, the current sensor 11 is fed to the output of the device and through the feedback circuit to the input of the control unit 3, where the output voltage is regulated by software. It should be noted that the dual modulation of high-frequency voltage - amplitude and PWM - allows you to get high quality output voltage in a wide range of input voltage.

If the voltage in the network uin is greater than the specified output Uout (Fig. 3, a), then it is supplied through the transformer 4, rectifiers 5 and 6 to the control switches 7 and 8, where PWM modulation of the input voltage uвx is carried out (Fig. 3, b) , the regulating key 7 is in the positive half-wave (Fig. 3, c), and 8 is in the negative (Fig. 3, d). Next, the voltage supplied to the smoothing filter 10, the output of which takes the form of Uout (Fig.3, b). To transfer to the load in a currentless pause (control key 7 or 8 off) the energy stored in the inductor of the smoothing filter 10 is an electronic switch with controlled conductivity 9, in the presence of a control signal at the first (Fig. 3, d), the current flows in the direction “ 0 ”- smoothing filter 10 with a positive polarity of the input voltage uvx, in the presence of a control signal at another control input (Fig.3, e) - in the opposite direction with a negative polarity of the input voltage uvx. In the absence of control signals, the electronic key with controlled conductivity 9 is turned off. The control keys 9, 10 are controlled by the control unit 3. The smoothed voltage after the filter 10, through the current sensor 11 is supplied to the output of the device and through the feedback circuit to the input of the control unit 3.

Sources of information

1. A.S. No. 789985 from 12.23.80 g. The method of discrete control of AC voltage. V.E. Boltnev, V.P. Milovzorov, A.K. Musolin.

2. Patent of Russia №2155365 C2 from 08.27.00, the Method of regulating AC voltage. B.C. Klimash.

3. Patent of Russia No. 2100837 C1 dated December 27, 1997. The AC voltage stabilizer. Feigin L.Z., Mikhalev S.I.

4. Patent of Russia №2123717 C1 dated 12/20/98. Electronic voltage stabilizer. G.G. Shop, L.T. Shop.

Claims (3)

1. A method of regulating voltage of any kind, based on the addition of high-frequency voltage with increasing voltage, characterized in that the input voltage is rectified, converted to alternating high-frequency voltage with amplitude and pulse-width modulation, transform, transform with a positive polarity of the input voltage into a unipolar voltage of positive polarity, and with a negative polarity of the input voltage - into a unipolar voltage of negative polarity, summarize with I single voltage and smooth at the output, and lowering the input voltage is carried out using pulse-width modulation and smooth at the output. 2. A voltage control device of any kind, containing a transformer, a control key, a current sensor, characterized in that a second control key is additionally inserted into it, a rectifier is included at the input of the device, the output of which is connected to the power bus of the high-frequency converter, the control inputs of which are connected to the unit control, and the output is connected to the primary winding of the transformer, the secondary winding of which is connected by the midpoint to the input voltage phase wire, and the other two leads to the input I will give rectifiers of positive and negative polarities, the outputs of which through the corresponding control keys are connected to the smoothing filter and the first output of the electronic key with controlled conductivity, the second output of which is connected to the neutral wire, and the control inputs of the electronic key with controlled conductivity are connected to the control unit, the output of the smoothing filter through a current sensor connected to the output of the device and through the feedback circuit to the control unit, the other two inputs of which are connected to the phase ode and the current sensor output, and control inputs regulate the keys are connected to outputs of the control unit. 3. The device according to claim 2, characterized in that the control unit is a microcontroller and incorporates a program control unit, pulse-width modulators and an analog-to-digital converter.

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