SU943593A1 - Device for measuring alternating current active power - Google Patents

Description

one

The invention relates to a measurement technique and can be used to convert active ac-to-ac power to direct current voltage.

A device for measuring active power is known, containing current and voltage sensors whose outputs are connected to the inputs of a Hall sensor 1.

The disadvantage of the device is low accuracy due to the presence of ripples in the output signal.

It is also known a device for measuring the active power of an alternating current, comprising a current transformer and a voltage transformer, the first windings of which are connected in series according to and connected to the input of the first rectifier, the second windings of current transformers and voltage are connected in series and counter to the input of the second rectifier, The first output pins of the rectifiers are combined and connected to the first input pins of the quadrants, the second input pins of which are connected to the second output pins of the corresponding t23 rectifiers,

The disadvantage of the device is low speed.

The purpose of the invention is to increase speed.

Claims (2)

The goal is achieved by the fact that, in a device for measuring, the active power of an alternating motor comprising a current transformer and a voltage transformer, the first windings of which are connected in series according to and connected to the input of the first rectifier, the second windings of current transformers and voltage are connected in series and counter connected to the input of the second rectifier, the first output pins of the connectors are combined and connected to the first input pins of the quadrants, the second input pins of which are connected to the second The output pins of the corresponding rectifiers, an extremator, a key and a memory block are inserted, the output of the first quad is connected to the key input, and through an extremator to its control input, the memory block is connected between the output of the key connected to the output bus, and common bus, which is connected to the output of the second quad. The drawing shows a diagram of a device for measuring active ac power. The device contains a current transformer 1, a voltage transformer 2, a first rectifier 3, a second rectifier, quadrants 5 and 6, an extremator 7, a key 8, a memory block 9. The device works as follows. The sum and difference of the voltages of the current transformer 1 and the voltage transformer 2 are fed to the motor rectifiers 3 and k, respectively. Straightened voltages are input to quadrants 5 and 6, where they are squared. The voltage between the outputs of the quadrants is proportional to the difference of the squares of the voltages arriving at their inputs, i.e. instantaneous ac power. With a resistive load (cos H 1), the amplitude of the instantaneous power is proportional to the average value of the active AC power (with a reactive load, compensation is required). The extremmer 7 selects the instantaneous power transition point through the maximum and generates at this point a short pulse arriving at the control input of the key 8. The key 8 opens for the duration of the pulse and the memory block 9, made in the form of a capacitor, receives a signal equal to the amplitude of the instantaneous power, which is stored for a time until the next extremum. For matching the device with the load, the memory unit can be connected to the output bus through the matching amplifier 10. At the output of the matching amplifier there is a constant signal proportional to the average active power at active load (CO 1). High speed is determined by the fact that the information in memory block 9 is updated at the extremum of the instantaneous power, as a result of which only a delay occurs in the device, determined by the time between adjacent extremes. Apparatus of the Invention A device for measuring the active power of an alternating current, comprising a current transformer and a voltage transformer, the first windings of which are connected in series according to and connected to the input of the first rectifier, the second windings of current transformers and voltage are connected in series to and opposite to the input of the second rectifier , the first output terminals of the rectifiers are combined and connected to the first input terminals of the quadrants, the second input terminals of which are connected to the second output terminals With appropriate rectifiers, characterized in that, in order to increase speed, an extremator, a key and a memory block are inserted into it, the output of the first quad is connected to the key input, and through an extremer to its control input, the memory block is connected between the output of the key, which is connected to the output bus, and the common bus to which the output of the second quad is connected. Sources of information taken into account during the examination 1. Kushnir F.V., Savenko V.G. Electroradio measurements. L., Energie, 1975, 0 .. 2. USSR author's certificate number 646266, cl. Q 01 R 21/00.07.12.77