RU2494436C1 - Ac voltage regulator - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: AC voltage regulator comprises a control element of discrete action, connected between input and output leads, and also a counter, a clock driver connected with an input to input leads, and with an output - to the count input of the counter, and a circuit of code comparison, the first input of which is connected to the output of the calculation unit, the second input - to the counter output, and the following components are introduced: a unit of existing value meters, outputs of which are connected to inputs of analogue comparators and to inputs of two analogue multiplexors, a combination device, inputs of which are connected to outputs of analogue comparators, and the output is connected to one of inputs of a summator and address inputs of analogue multiplexers, a unit of analogue comparators, two multiplexors, outputs of which are connected with inputs of the ADC unit, to the input of which a signal is also connected from a setpoint setter, a calculation unit, to inputs of which ADC outputs are connected, and the output is connected to one of inputs of the code comparison circuit, and a setpoint setter.

EFFECT: increased stability of existing voltage value at a regulator output.

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Description

The present invention relates to the field of electrical engineering and may find application in systems of precision control of technological parameters, in particular in temperature controllers.

Known AC voltage regulator containing a discrete action regulator connected between input and output terminals, an analog-to-digital converter connected by an input to the terminals for connecting a control signal, a clock driver connected by an input to the input terminals, and the output to the counter input of the counter, source signals “log.0”, an adder, the first input of which is connected to the higher bits of the analog-to-digital converter, and the output - to the control inputs of the regulator action, and a comparator, the first input of which is connected to the output of the least significant bits of the analog-to-digital converter, the second input - with the output of the counter, and the output - with the least significant bit of the second input of the adder, the highest bits of which are connected to the output of the signal source “log.0” [ A.S. 1325431 SU, G05F 1/20, AC Voltage Regulator].

The disadvantage of this controller is the non-uniformity of the control characteristic, expressed in the deviation of the power increment in the load from the calculated value during regulation, which is due to deviations of the parameters of the control windings and keys from the nominal values.

Closer in technical essence to the proposed technical solution is an AC voltage regulator containing a discrete regulating element connected between input and output terminals, an analog-to-digital converter connected to an input with terminals for connecting a control signal, as well as a counter, a clock generator, connected to an input to the input pins, and the output to the counting input of the counter, the signal source is “log.0”, an adder, the first input of which is connected to the higher bits of the of the digital-to-digital converter, and the output - with the control inputs of the regulating body of discrete action, and a comparator, the first input of which is connected to the output of the least significant bits of the analog-digital converter, the second input - with the output of the counter, and the output - with the least significant bit of the second input of the adder, the older ones the bits of which are connected to the output of the signal source "log.0", a code converter, the input of which is connected to the outputs of the upper bits of the analog-to-digital converter, and the output - with the installation input of the counter [A.s. 2386993 C1, G05F 1/00, AC voltage regulator].

The disadvantage of this voltage regulator is that a transformer acts as a discrete regulating body, in which the secondary winding is partitioned so that the number of turns in the various sections are treated as integers of degree two, which requires the manufacture of special transformers. Another disadvantage is the deviation of the voltage at the output of the regulator from the set value with instability of the supply network. Programming the code converter is based on a specific value of the supply voltage. Therefore, the deviation of the supply voltage from the nominal will not allow to obtain the required effective voltage value at the regulator output.

The technical result of the invention is to increase the stability of the current value of the voltage at the output of the regulator, as well as to improve the technical feasibility, expressed in the possibility of using any sectioned transformers as a discrete regulatory body.

The technical result is achieved by the fact that in the known AC voltage regulator containing a discrete action regulator included between the input and output terminals, as well as a counter, a clock driver connected to the input terminals by the input and the output to the counter counter input, and a code comparison circuit , the first input of which is connected to the output of the calculation unit, the second input - to the output of the counter, a block of current value meters is introduced, the outputs of which are connected to the inputs of the analog comparators and with the inputs of two analog multiplexers, a combinational device whose inputs are connected to the outputs of the analog comparators, and the output is connected to one of the inputs of the adder and the address inputs of the analog multiplexers, the block of analog comparators, two multiplexers, the outputs of which are connected to the inputs of the ADC block, the input of which is also the signal from the setpoint adjuster is connected, the calculation unit, to the inputs of which the ADC outputs are connected, and the output is connected to one of the inputs of the code comparison circuit and the setpoint adjuster.

The circuit of the proposed AC voltage regulator is shown in figure 1. It contains a clock generator 1, the inputs of which are connected to the input terminals of a discretely controlled transformer (DRT), and the output is connected to the counting input of the counter 6, the decoder 2, the input of which is connected to the output of the adder 4. The outputs of the decoder 2 are connected to the corresponding electronic keys of the sections of the DRT . One of the inputs of the adder 4 is connected by the low order with the output of the code comparison circuit 5, and the remaining bits with the output of the logical zero source 3, the other input of the adder 4 is connected to the output of the combinational device 7. The outputs of the measuring unit 9 of the actual value are connected to the inputs of the analog comparators 8. The outputs of the block of analog comparators 8 go to the inputs of the combination device 7. The output of the combination device 7 is connected to one of the inputs of the adder 4 and to the address inputs of the multiplexers 13 and 14. The outputs of the multip lexors are connected to the inputs of the ADC block 11, to another input of which a signal is supplied from the output of the setpoint adjuster 10. The inputs of the calculation block 12 are connected to the output of the ADC block, and the output of the calculation block is connected to one of the inputs of the code comparison circuit. The setpoint adjuster 10 is connected to one of the inputs of each analog comparator.

The clock generator 1 is made on a 554CAZ chip, counter 6, a logic zero source 3, a decoder 2, an adder 4, a code comparison circuit 5, a combination device 7, a calculation unit 12 can be performed on an AT90S1200 microcontroller chip. Analog multiplexers 13 and 14 can be performed on a 590KN1 chip. Measuring instruments of actual value 9 can be built on microcircuits LH0091. For the ADC block 11 can be used chip AD9634. The block of analog comparators can be performed on operational amplifiers LM741.

Figure 2 shows timing diagrams explaining the principle of operation of the proposed AC voltage regulator. The work of the proposed AC voltage regulator is as follows. In the initial state, the contents of the counter are zero. At the start of each regulation period, the calculating unit 12 calculates the switching moment and outputs it to the input of the code comparison circuit 5. The clock generator 1 generates short pulses from the mains voltage corresponding to the beginning of each half-period of the mains voltage. With the beginning of the half-cycle, the pulse from the output of the generator 1 clock goes to the counting input of the counter 6, which increments the contents of the counter. The code s from the output of counter 6 is supplied to one of the outputs of the code comparison circuit 5, which compares it with the q code supplied to the second input from the calculation unit 12. The q code determines the moment of switching between the discrete voltage levels. If (s <q), then the output of the code comparison circuit 5 is a logic zero signal (r = 0), otherwise a logical unit (r = 1). The value of r from the output of the code comparison circuit 5 goes to the least significant bit of one of the inputs of the adder 4, to the second input of which a value is supplied from the combinational device 7, which determines the number of the connected section at the beginning of the control cycle. After overflow counter 6 begins a new cycle of regulation. Further, the operation of the device is repeated.

The power at the load will be determined by the following expression

$$P=\frac{n}{N}\cdot P_{\mathrm{one}}+\frac{(N-n)}{N}\cdot P_2(\mathrm{one})$$

where n is the number of half-periods of the network when a section with a power of P _{1 is} connected to the load;

N is the duration of the control cycle in half periods of the network;

P ₁ and P ₂ are the power of the initial and final level, respectively.

Since the power is directly proportional to the square of the effective voltage value, we obtain the following formula

$$U_{de\mathrm{th}\mathrm{from}t}^2=\frac{n}{N}\cdot U_{d\mathrm{one}}^2+\frac{(N-n)}{N}\cdot U_{d2}^2(2)$$

Express n from the above expression

$$n=\frac{N\cdot (U_{d2}^2-U_{de\mathrm{th}\mathrm{from}t}^2)}{U_{d2}^2-U_{d\mathrm{one}}^2}(3)$$

Based on this expression, you can find the moment of switching from one section to another (the number of half-periods of the mains voltage when the initial section is connected). For this, it is necessary to know the effective voltages of the initial and final sections U _d1 and U _d2, respectively, as well as the effective voltage U _deyst , which must be obtained at the load.

Figure 3 shows the connection diagram of the meters to the sections of the DRT. Each meter gives an analog signal V _i proportional to the current voltage of the section. Moreover, V ₁ <V ₂ <V ₃ <... <V _m-1 <V _m .

The signals from the meters are fed to the block of analog comparators, each of which compares the level of the section V _i with the setpoint V _{0 of the} effective voltage value at the load.

An analog comparator generates a signal of a logical unit if the setpoint level is greater than the signal from the meter of the actual value, otherwise a logical zero. The set point cannot be less than the minimum voltage and more than the maximum voltage generated by the DRT, which means that the signals from the first and last meters can be excluded from analysis to determine the number of the section connected at the beginning of the regulation period, since their ratio with the set point is predefined (V ₀ > V ₁ , V ₀ <V ₅ always).

A combinational device (KU) summarizes the signals received at its inputs from analog comparators, and the result in the form of a k-bit code is output. The capacity of the code k at the output of the control unit depends on the number of sections of the DRT and is found by formula (4) with rounding to the nearest whole number. The output of the control unit determines the number of the section connected at the beginning of the regulation period

$$k=lo{g}_{2}m(\mathrm{four})$$

where m is the number of sections of the DRT.

For example, the setpoint value V ₀ is between the signals of the V ₃ and V ₄ meters, that is, V _{0 is} greater than V ₁ V ₂ , V ₃ , and less than V ₄ , V ₅ , ..., V _m . In this case, the logic unit will go to the control unit from the analog comparators AK ₁ and AK ₂ , and the remaining inputs of the control unit will have zeros. After summing, the output will be binary code 10 ₂ , which means that at the beginning of the regulation period, the logical unit will be fed to the electronic key K3.

The code from the outputs of the KU goes to one of the inputs of the adder 4. Also, the code from the output of the KU goes to the address inputs of the multiplexers. The multiplexer (13) attaches the actual value of the initial level to its output, and the multiplexer (14) - connects the effective value of the final level. The signals from the outputs of the multiplexers and the setting value are converted using the ADC block into binary codes and are fed to the computer inputs. The computer according to the formula (3) calculates the number of half-periods during which the initial voltage level is issued and gives it to the input of the code comparison circuit 5.

Compared with the known AC voltage regulator [2], when the voltage of the supply network changes, the voltage regulator determines the numbers of the connected sections and recounts the switching time between them so that the effective voltage at the output of the regulator corresponds to the setting. No reprogramming of the controller elements is required when using other discrete transformers with the same number of sections.

Claims (1)

An AC voltage regulator containing a discrete action regulator connected between input and output terminals, as well as a counter, a clock driver, connected by an input to the input terminals, and an output to a counter input of a counter, and a code comparison circuit, the first input of which is connected to the output of the unit calculations, the second input - with the output of the counter, characterized in that a block of meters of actual value is inserted into it, the outputs of which are connected to the inputs of analog comparators and to the inputs of two analog ultiplexers, a combinational device, the inputs of which are connected to the outputs of the analog comparators, and the output is connected to one of the inputs of the adder and the address inputs of the analog multiplexers, the block of analog comparators, two multiplexers, the outputs of which are connected to the inputs of the ADC block, to the input of which the signal from the master is also connected settings, the calculation unit, to the inputs of which the outputs of the ADC block are connected, and the output is connected to one of the inputs of the code comparison circuit, and the setpoint adjuster.

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