RU2364915C1 - High-precision electronic ac voltage controller - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: invention relates to electrical engineering, particularly AC voltage controller (stabilisers) and can be used in power supply circuits to stabilise single-phase AC power supply source. There is a known AC voltage controller that comprises summing transformer and autotransformer, switch, stabiliser control device with micro controller and sync pulse counter, input and output voltage pickups, current sync pulse pickup, load current pickup, controller state data display, and terminals for connection to the circuit and load. Autotransformer comprises two sets of taps, i.e. coarse-adjustment taps and fine-adjustment taps, the number of the former making m and that of the latter making k. Note here that voltage booster connected in between adjacent coarse-adjustment taps notable exceeds that between adjacent fine-adjustment taps. Connection of two taps, one from the course-adjustment set and one of fine-adjustment set, allows generation of a number of voltages with minor discreteness and with the number of control stages equal to N = m·k, where m is the number coarse-adjustment taps and k is the number of fine-adjustment taps.

EFFECT: higher reliability and accuracy, lower production costs.

7 cl, 1 dwg

Description

The invention relates to electrical engineering, in particular to regulators (stabilizers) of AC voltage, and is intended for use in power supply systems to stabilize a single-phase voltage source of AC electric power and in devices where there is a need for precise voltage regulation.

A known AC voltage stabilizer containing a circuit breaker, as well as a transformer, thyristor switches as a switch for non-contact switching of transformer branches and a stabilizer control device that contains a power supply, a zero-organ and a pulse shaper (see Rozanov Yu. K. Fundamentals of power electronics . - M.: Energoatomizdat, 1992 .-- 296 p., Fig. 59, p. 238). The disadvantages of the stabilizer are low reliability and efficiency, which prevents the technical result, which is provided by the invention.

Known AC voltage stabilizer containing a transformer with a main, additional and measuring windings. The beginning of the main winding is the input and output terminals of the stabilizer. The stabilizer also contains power sources and a reference voltage, a half-wave rectifier with an RC filter at the output, voltage comparators whose inverting inputs are connected through a resistor to a reference voltage source, and non-inverting inputs are also connected to the output of the RC filter through resistors.

The stabilizer also contains transistor amplifiers, electromagnetic relays with switching contacts (see the patent of the Russian Federation for the invention RU 2187834, 7 cl. G05F 1/20, 2001). The disadvantages of the stabilizer are low reliability and efficiency, which prevents the technical result, which is provided by the invention.

The closest device of the same purpose to the claimed invention is an AC voltage stabilizer containing a transformer, a switch made in the form of keys for switching branches of a transformer, and a stabilizer control device that contains a power supply, a zero-organ and pulse shapers, used as a transformer autotransformer, and as keys, respectively, optosymistors, and a power source is connected to the input and the general output of the autotransformer, and its rvy and second terminals through the first and second optosimistory connected to the first output of the stabilizer, the second output of which is the total output of the autotransformer. The stabilizer control device further comprises a sawtooth voltage generator, a comparator, where the first and second inputs of the power supply are connected to the input and the general output of the autotransformer, respectively, the first output of the power supply is connected to the input of the zero-organ, the output of which is connected to the input of the sawtooth voltage generator and the input of the first driver control pulses, the second output of the power supply is connected to the first input of the comparator, the second input of which is connected to the output of the sawtooth generator the output of the comparator is connected to the input of the second control pulse shaper, while the outputs of the first and second control shapers are connected to the control inputs of the first and second opto-sims. The stabilizer contains terminals (input terminals 6 and 7, output terminals 10 and 11), a circuit breaker and a protective earth terminal (see patent of the Russian Federation for invention RU 2216032, class 7 G05F 1/20, 2002).

The disadvantages of the stabilizer are a small range of regulation and pulse-phase control of opto-sims, which leads to inevitable distortion of the mains voltage, which is unacceptable.

The closest device of the same purpose to the claimed invention, taken as a prototype (see the patent of the Russian Federation for the invention RU 2188496 C1 7, CL H2M 5/12, G05F 1/30, 2002), is a device for stepwise regulation of AC voltage. This device contains input and output terminals, a first transformer having a main winding connected to the input output of the device, and a sectioned winding for lowering and / or increasing voltage, the soldering of which is connected to the corresponding terminals of the control switches of the first group of switches, managed switches of the second group of switches, inputs which are connected to the corresponding taps of the partitioned winding of the first transformer, the summing divider, the first and second inputs of which are connected Through the first and second keys, respectively, to the terminals of the control switches of the first and second groups of switches, respectively, and a second transformer, one of the windings of which is connected between the input and output terminals of the device, and the other winding is connected to the output of the summing divider.

The disadvantages of this device are:

1) the impossibility of fine adjustment,

2) a large number of taps at the partitioned winding of the primary transformer to obtain more accurate adjustment of the output voltage of the load at the output of the second transformer,

3) the impossibility of reversing, the device can only be raising the voltage or only lowering.

The purpose of the invention is to increase the accuracy of the readings (adjustments) of a high-precision AC voltage regulator (hereinafter referred to as the regulator), simplify the design of the device, increase reliability and durability, increase the range of regulation, as well as simplify adjustment and reduce the cost of the device.

This goal is achieved by the fact that in the already known AC voltage regulator, including summing and autotransformers, a switch, a stabilizer control device with a microcontroller and clock sensors, input and output voltage, a current clock sensor, a load current sensor, a device for displaying information about the state of the regulator, load connection device with an amplifier and magnetic starter located in the housing, as well as terminals for connecting to the network and the load, autos Mator and grounding contacts, contains two groups of taps, a group of taps of coarse adjustment with the number of taps = m and a group of taps of fine adjustment with the number of taps = k, and the voltage addition between adjacent taps of coarse adjustment significantly exceeds the voltage addition between adjacent taps of fine adjustment, a combination of connecting two taps one of the fine adjustment group and one of the coarse adjustment group allows to obtain a series of voltages with low resolution and with the number of adjustment steps equal to

,

,

where m is the number of taps of coarse adjustment;

k is the number of taps of fine adjustment.

The number of taps of the exact group m and voltage addition - voltage change during the transition of the connection to adjacent taps of the exact group, determines the accuracy of the voltage regulator, and the number of taps of the rough group k and the voltage difference between the extreme taps of the rough group determines the control range.

If the taps of the fine adjustment are located on one side of the taps of the coarse adjustment, then the polarity is maintained when two taps, one of the exact group and one of the coarse group are connected in any combination, and if the taps of the exact adjustment group are located between two adjacent coarse taps, then the polarity changes when two taps are connected, one of the exact group and one of the coarse group when a coarse group tap is located located on one or the other side of the exact tap group Adjusting. Two autotransformer taps are connected to the summing transformer, one tap from the fine-tuning group is connected through the pin-type current-limiting resistors and a fine-tuning switch and one tap from the coarse-tuning group, through the coarse-tuning current-limiting resistors and the coarse switching.

The drawing shows a functional diagram of a high-precision electronic voltage regulator.

Regulator 1 contains an adjustment block 2, which includes an autotransformer 13, with two groups of taps: - coarse adjustment B1 --- Bm - and fine adjustment -A1 --- Ak, which are connected through the corresponding groups of current-limiting coarse-adjustment resistors - 19 and a group fine-tuning current-limiting resistors - 16 through coarse fuse groups - 18 and fine - 15 adjustment to the corresponding fine adjustment switches - 14 and coarse adjustment - 17 and to the voltage-boost winding of the summing transformer 12, and ovnaya winding of the summing transformer is connected to the input and output of the network load. The controller control device 2 contains a microcontroller 3, the inputs of which are connected to an input voltage sensor 4, a voltage synchronization sensor 5, an output voltage sensor 6, a load current sensor 20, a current synchronization sensor 10, and the outputs of the microcontroller 3 are connected to the control inputs of the coarse voltage adjustment switch 17 and control inputs of the switch for fine adjustment of voltage 14, a device for displaying information about the state of the stabilizer 11, and a device for connecting a load 21, consisting of the amplifier 22 and the magnetic starter 23, as well as the ground contacts 24. The switches (switches) are designed as electronic thyristor blocks (other types of switches are possible: for example, based on transistors or triacs), consisting of pairs of counter-connected thyristors connected through fuse groups and current limiting resistor groups with autotransformer taps.

The regulator operates as follows: the input voltage from terminals 7 after turning on the circuit breaker 8 is supplied to the main winding of the summing transformer 12. The microcontroller 3, using the input voltage sensor 4, measures the input voltage and determines which two taps must be connected to the boost coil of the power transformer, moreover, one tap is taken from the group of taps B1 --- Bm of coarse adjustment and the second tap is taken from the group of taps A1 --- Ak of fine adjustment of autotransformat and 13 and delivers the commands to the control inputs of switches accurate - 14 and rough - 17 adjustment so that after the magnetic actuator 23 in the load connecting unit 21 corresponds to the load voltage set value of the output voltage, since the initial insertion is made regulator.

Further operation of the controller occurs as follows: when the input voltage is changed using the input voltage sensor 4 in the rated voltage range of the network, the controller control device 2 sends commands to the control inputs of the switches with precise - 14 and coarse - 17 settings, which through the fuse groups are accurate - 15 and coarse - 18 adjustments and groups of current-limiting resistors precise - 16 and coarse - 19 adjust switch taps - B1 --- Bm and - A1 --- Ak autotransformer 13 so as to provide on ltodobavochnoy winding of the summing transformer 12, a voltage value, which after the magnetic actuator 23 in the device 21 and the load connection with the transformation ratio provides the output of the summing transformer voltage equal to the output voltage adjusting value. The autotransformer taps are connected by a regulator control device by means of a microcontroller and a control program recorded in it. Depending on the readings of the input voltage sensors, two autotransformer taps are selected for connection: one from the taps of the exact group and one from the taps of the coarse adjustment group.

With small changes (fluctuations) in the voltage of the network, voltage regulation is carried out by switching one of the taps within the exact control group, and when the deviations of the input voltage exceed the limits of their regulation due to switching taps within the exact group, the next closest tap is switched within rough adjustment group.

Using an autotransformer to control a summing transformer can significantly reduce the currents flowing through the autotransformer windings, thyristor switches, current-limiting resistors and fuses, due to the use of a summing transformer with a transformation coefficient significantly greater than 1.

The stabilization accuracy is achieved due to the fact that the autotransformer contains two groups of taps, a group of taps of coarse adjustment B1 --- Bm - with the number of taps = m and a group of taps of fine adjustment -A1 --- Ak - with the number of taps = k, and the voltage addition between adjacent coarse adjustment taps significantly exceeds the voltage addition between adjacent fine adjustment taps, and the combination of connecting two taps of one of the fine adjustment group and one of the coarse adjustment group allows to obtain a series of voltages with a small discrete NOSTA and a number of values equal to

,

,

where m is the number of taps of coarse adjustment;

k is the number of taps of fine adjustment.

- (изменение напряжения при переходе подключения на соседние отводы точной группы автотрансформатора), подбирается с таким расчетом, чтобы обеспечить необходимую точность регулятора напряжения, а число отводов грубой группы k и вольтдобавка

(изменение напряжения при переходе подключения на соседние отводы грубой группы автотрансформатора) и разность напряжения между крайними отводами грубой группы с одной стороны от отводов точной группы и с другой стороны от отводов точной группы подбираются из условия обеспечения необходимого диапазона регулирования как в сторону увеличения напряжения, так и в сторону его увеличения. Примерная зависимость между вольтдобавками

и

следующая:Moreover, the number of taps of the exact group m and voltage addition

- (voltage change during the transition of the connection to neighboring branches of the exact autotransformer group), is selected so as to ensure the necessary accuracy of the voltage regulator, and the number of taps of the rough group k and voltage addition

(voltage change when connecting to adjacent taps of the coarse group of the autotransformer) and the voltage difference between the extreme taps of the coarse group on the one hand from the taps of the exact group and on the other hand from the taps of the exact group are selected from the condition of ensuring the necessary control range both in the direction of increasing voltage, and in the direction of its increase. Approximate relationship between voltage boosts

and

following:

The change in voltage at the output of the power transformer is determined taking into account the transformation coefficient C as:

If the taps of the exact adjustment group are located between two adjacent coarse adjustment taps, then the polarity changes when two taps are connected, one of the exact group and one of the coarse group, when the tapping of the coarse group located on one or the other side of the exact taps group is taken adjustments. It is also possible that the fine adjustment taps are located on one side of the coarse taps, while polarity is maintained when two taps, one of the exact group and one of the coarse group, are connected in any combination.

With small changes in the voltage level in the network, voltage adjustment is carried out by switching the taps of the exact autotransformer adjustment group, and with large changes in the voltage value in the network when adjustment is impossible only by switching the taps within the exact group, the necessary branch of the rough adjustment group is switched.

A high voltage regulation speed is achieved by a high speed of measuring the sampling parameters for measuring the input voltage, output voltage, load current for one period of the mains voltage, and switching the autotransformer to other taps with switch keys when the phase of the load current passes through zero, which eliminates network voltage distortion.

The measurement results of the input and output voltages, power, load, and other auxiliary parameters, the microcontroller outputs to the device 14 display information about the status of the controller. When the input voltage changes in the nominal range, the control device of controller 2 sends commands to the control inputs of the switch, which connects one of the coarse and one of the exact taps of the autotransformer in such a way as to provide a voltage of such magnitude on the voltage-boost winding of the summing transformer 12 that, taking into account the transformation coefficient, provides the load voltage corresponding to the installation value of the output voltage within the permissible error.

Switching is performed after the microcontroller determines, with the help of a current synchronization sensor 5, the moment the load current passes through zero. The stabilization accuracy is determined by the voltage between adjacent taps of accurate autotransformer adjustment, so with 6 coarse and 6 accurate autotransformer taps, the nominal input voltage range is from 130 V to 260 V with stabilization accuracy of ± 1.5%, and switching at zero load current eliminates voltage distortion network.

If the input voltage exceeds the operating range, which slightly exceeds the nominal range, the controller control device disconnects the load by turning on the magnetic starter 23 in the load connection device 21, then the switch disconnects all autotransformer taps involved in the regulation, the output voltage to the terminals is stopped . After normalizing the input voltage, that is, when the input voltage reaches the operating range, the control device resumes the work to stabilize the output voltage. In addition, the regulator control device monitors a number of emergency situations, when they occur, the output voltage to the load connection terminals is cut off. The microcontroller outputs information about emergency situations to the device displaying information about the status of the regulator.

Thus, the proposed controller allows to increase reliability by reducing the current in the circuit of electronic switches, to increase the speed of the controller, to obtain high adjustment accuracy with a minimum number of keys in the switches and taps in the autotransformer, while the cost of the AC voltage regulator is reduced, which is a technical result.

Claims (7)

1. An electronic voltage regulator comprising a control unit with a summing transformer, an autotransformer and switches, a control device with a microcontroller, a clock sensor, an input voltage sensor and an output voltage sensor, in addition, a current clock sensor, a load current sensor, an electronic state information display device voltage regulator, a load connection device with an amplifier and a magnetic starter located in the housing, as well as terminals for connecting I to the network and the load and ground contacts, characterized in that the autotransformer contains a group of taps for coarse adjustment with the number of taps m and a group of taps for fine adjustment with the number of taps k, and the voltage between adjacent taps for coarse adjustment exceeds the voltage between adjacent taps for fine adjustment, one tap from the fine adjustment group and one tap from the coarse adjustment group are connected to the summing transformer. 2. The electronic controller according to claim 1, characterized in that the combination of connecting two taps of the autotransformer of one of the group for fine adjustment and one of the group for coarse adjustment allows you to get a number of voltages with low resolution and with the number of levels N = m · k. 3. The electronic regulator according to claim 1, characterized in that the number of taps of the group k for fine adjustment and the voltage change when switching the connection to neighboring taps of the group for fine adjustment is selected so as to ensure the necessary accuracy of the electronic voltage regulator. 4. The electronic controller according to claim 1, characterized in that the number of taps m groups for coarse adjustment and the voltage difference between the extreme taps of the group for coarse adjustment is selected from the condition of ensuring the necessary control range. 5. The electronic controller according to claim 1, characterized in that the taps of the group for fine adjustment are located on one side of the taps of the group for coarse adjustment, while maintaining polarity when connecting in any combination of two taps, one of the group for fine adjustment and one of groups for coarse adjustment. 6. The electronic controller according to claim 1, characterized in that the taps of the group for fine adjustment are located between two adjacent taps of the group for coarse adjustment, while the polarity changes when two taps are connected, one of the group for fine adjustment and one of the group for coarse adjustment when a branch is taken from the group for coarse adjustment located on one or the other side of the group taps for fine adjustment. 7. The electronic controller according to claim 1, characterized in that two autotransformer taps are connected to a summing transformer, one tap from the group for fine adjustment is connected through a group of current-limiting fine adjustment resistors and a switch for fine adjustment, and one tap from the group for coarse adjustment through a current-limiting group coarse adjustment resistors and coarse adjustment switch.