SU442430A1 - Measuring converter of alternating voltage in constant - Google Patents

Description

one

This invention relates to electrical measuring technology.

An alternating-voltage-to-constant voltage measuring transducer is known, comprising a memory device, two switches, a non-linear converter and a comparison device, the first switch being connected to the memory input.

Such a converter has a low measurement accuracy and low speed.

The purpose of the invention is to improve the accuracy of the response of the variable voltage to constant voltage transducer.

To achieve this goal, a reference voltage source is inserted in it, connected to one of the inputs of the comparison device, to the other input of which a series-connected nonlinear converter and a memory device are connected, the input of the measuring converter being connected to the output of the first and second switches, and the second switch furthermore associated with a second memory input.

FIG. 1 is a block diagram of a measurement transducer; in fig. 2 shows a simplified schematic diagram of a converter.

The proposed transducer of the effective value of alternating voltage to constant contains a nonlinear converter 1, a memory device made in the form of an adjustable memory divider 2 (RZD), a comparison device 3 with a supporting element 4, switches 5 and 6. Between the adjustable memory divider 2 and a nonlinear converter 1, a power limiter amplifier can be switched on, and a storage amplifier at the output of the linear converter.

The 1-1 measuring converter of alternating voltage to constant multi-temporal comparison 5 operates according to the method of equivalent effects and has two work cycles — preparatory and working.

In the preparatory cycle, switches 5 and 6 are in position b. At the same time, the input of the adjustable memory divider is connected to the input of the linear converter, and the output of the comparison device to the control circuit of the said divider.

The AC signal to be converted is fed through divider 2 to the input of nonlinear converter 1 and is converted to a DC signal, which is compared to a reference source by a comparison device 4. The error signal is amplified by 0 by a comparison device 3 and acts

to the control circuit of divider 2, changing its division ratio to a value at which the signal Ln at the output of converter 1 becomes equal to the signal t / o of the reference source 4.

In this case, the input signal L will be associated with the signal UE and the reference signal Uo by the following expression:

and „and, to, to, and

where / Ci is the division factor of divider 2, Kz is the conversion coefficient of nonlinear converter 1. In the operating cycle, switches 5 and 6 are set to a, i.e. the input of divider 2 is disconnected from the input of the linear converter and connected to the output of a comparator device 3. When this preserves the division factor of divider 2 set in the previous preparatory cycle. Under the action of negative feedback, after contacts a of switches 5 and 6, at the input of the comparison device 3, after the end of the transient process, a state is established in which the Un signal at the output of the converter 1 becomes equal to the signal of the reference source 4. The output of the comparison device and will be associated with the t / n signal and the t / o reference signal with the following expression:

and, and, K, -K, -i. (2)

Since in a short period of time sufficient for the end of the transition process, the value of Uo; / If K2 and s can change significantly, then equations 1 and 2 can be equated, i.e.

to, to, and to, to, and, and, and.

Thus, the proposed converter performs an accurate conversion of the effective value of the non-temporal current into a constant one.

FIG. 2 as an example, a schematic diagram of a linear converter is given, in which a thermal converter 1 is used as a nonlinear converter, and an adjustable storage divider 2 is made on an optocoupler and a memory storage amplifier. In the initial state from the output of the comparison amplifier 3 due to the reference source 4, the memory amplifier is given a maximum signal and the LED lights up most clearly, which reduces the resistance

photoresistor to the minimum value. The AC signal without attenuation is fed to the input of the thermocouple I. Thermo-emf. at the output of thermocouple 1 is compared with the reference emf. 4. The difference is amplified by amplifier 3 and fed to the input of an amplifier charger, which reduces the LED's glow until the resistance of the photoresistor increases to the value at which the thermal emf is. 4 equals emf reference source. The memory capacitance C maintains, during the operating cycle at the input of the memory amplifier, the signal necessary to maintain the resistance value R set in the first cycle.

Subject invention

AC voltage to DC converter containing a storage device, two switches, a non-linear converter and a comparison device, the first switch connected to the first memory input, characterized in that, in order to improve the accuracy and speed of measurement, a source is entered a reference voltage connected to one of the inputs of the comparison device, to the other input of which are connected a series-connected nonlinear converter and storage A device, the input of the measuring converter through the first n of the second commutator is connected to its output, and the second switch is also connected to the second input

storage device.