SU659971A1 - Ac voltage-to-dc voltage converter - Google Patents

Description

one

The invention relates to the field of instrumentation technology, in particular, the conversion of the amplitude of the alternating voltage into a proportional constant voltage according to the principle of self-compensation.

An alternating voltage to constant voltage converter containing a series-connected reference element and an expander 1 are known.

However, the drawback of the device is the slow establishment of the stationary mode, i.e. the dynamic equilibrium mode, and the difficulty of ensuring the synchronous operation of the first and second integrators.

An alternating voltage-to-voltage amplitude converter is also known, comprising a series-connected comparison element, an expander, an integrator, and a negative feedback circuit connecting the output of the integrator to one of the inputs of the comparison element 2.

However, a disadvantage of this converter is also the slow establishment of a steady state. This is due to the following. In order to ensure minimum output ripple voltage, the time constant of the expander is chosen to be minimal, but sufficient for stable operation of the integrator, which is slightly more than half

period of the input sinusoidal signal, and the time constant of the integrator is chosen much more than the time constant of the expander (tr). In this case, the sawtooth output voltage of the converter is not monotonic, but stepped with periodic ups and downs, which lengthens the process of the converter to a steady state. Attempting to speed up the establishment of a stationary mode by decreasing the constant integration results in an increase in the output voltage ripple of the converter.

The purpose of the invention is to increase the speed of the converter.

This is achieved in that a converter containing a comparison element and an expander, an integrator and a negative feedback circuit connecting the output of the integrator with one of the inputs of the comparison element is inserted in series with an offset element, an adder and an additional expander, as well as an OR logical element and an inverter . The expander input is connected to the inputs of the mixing element and the inverter, the output connected with one of the inputs of the adder. The output of the OR gate is connected to the integrator input, the first input is connected to the expander output, the second input is connected to the output of the additional expander.

The introduction of an additional extender has caused a change in the integrator mode of operation. Until the converter reaches the stationary mode, it forms a monotonously increasing sawtooth voltage. This is ensured by the fact that the second expander forms output voltages at times when the output voltage of the first expander is absent, which is why the control voltage is constantly maintained at the input of the integrator, which means that its output sawtooth voltage will quickly reach a level equal to the amplitude AC output signal.

FIG. 1 shows a block diagram of the device; in fig. 2 shows diagrams explaining the operation of the device.

The ac voltage-to-dc amplitude converter contains a comparison element 1 based on a differential amplifier, one input of which is connected to the input terminal and the second input to the output of integrator 2. The inputs of the main expander 3 are connected to the output of element 1 and through the offset element 4 and the adder 5 the input of the additional expander 6, and the output of the latter and the output of the expander 3 through the element OR 7 are connected to the input of the integrator 2. The output of the element 1 through the inverter 8 is connected to the second input of the adder 5.

The device works as follows.

When applied to the input device of a sinusoidal voltage at the output element

1 according to the amplitude amplified amplitude voltage (fig. 2), since the output voltage of the converter is zero at the first moment. When it is necessary to obtain a positive polarity at the output of the converter, the expander 3 perceives a positive half-wave and, through its output signal, through the element 7 acts on the integrator

2 such that an increasing sawtooth voltage of positive polarity arises at its output.

This effect periodically ceases after the positive half-wave disappears with a delay for the time of the expander 3. Termination of the output signal of the expander 3 could change the state of the integrator 2 and cause the voltage saw to fall. However, this does not occur, since there is an additional expander 6. The duration of the positive half-waves at the output of element 1 gradually decreases, and the negative-increases (Fig. 2). At the output of the inverter 8, the change in duration will be reversed. Due to the increased duration of the negative half wave

element 4 forms a progressively increasing negative voltage, i.e., acts as a negative voltage accumulator for each period of the signal of reference element 1. Totalizer 5 displaces or superimposes the signal of inverter 8 on the signal of the element of displacement 4. Therefore, at the output of the adder 5, a signal is formed with a constantly decreasing positive half-wave, which is controlled by an additional expander 6. At the moment the converter goes to a stationary mode, the amplitude of the positive half-wave becomes below the detection threshold of the expander 6. The last stop work on the converter circuit as a whole. Thus, the voltage saw of the integrator 2 does not have periodic drops and monotonously increases until the amplitude of the positive half-wave of the input voltage increases. In this case, the signal at the output of element 1 disappears, and at the output of element 7 - with a delay for a constant time of the expander 6. As a result, the sawing voltage of the integrator 2 begins. When the saw voltage becomes less than the amplitude of the positive half-wave of the input signal at the output of element 1 the signal again appears and the process is repeated. The extender b allows the negative half-wave to be used in the process of reaching the stationary mode of converting positive half-waves and vice versa, which ensures uninterrupted operation of the integrator and shortens the time required to establish the stationary mode of the converter.

Claims (2)

Invention Formula The ac voltage-to-voltage amplitude converter containing a serially connected reference element and an expander, an integrator and a negative feedback circuit connecting the output of the integrator to one of the inputs of the comparison element, characterized in that, in order to improve performance, the connected bias element, the adder and additional expander, as well as the OR logical element and the inverter, moreover, the input of the extender is connected with the inputs of the bias element and the inverter, output annogo with one of the adder inputs, the output of OR logic gate connected to the input of the integrator, a first input - to the output rasschiritel, the second input - to the output of the additional expander. Sources of information taken into account in the examination 1. Copyright certificate № 491106, cl. G OSH 19/22, 1972. 5 2. Variable voltage amplitude converter to constant, I-6-17, 6, CU 2204007, developed by KNIIRIT, Kaunas. COOLHiJJl Bbia iSHOv signal /6,--.ii7 si receiver i Vnad element inverter offset -f  ci M -jupijf / u SS Bb / ifoS Optional Expander