SU859997A1 - Device for quadrature component compensation - Google Patents

Description

The invention relates to automation and can be used in servo systems and other automated electric drives.

A device for compensating the quadrature component, comprising a demodulator, a smoothing filter, a correcting DC link, a modulator, as well as a source of alternating switching voltage [1].

The disadvantage of such a corrective suppressor is the significant delay introduced by the smoothing filter if its constant time is 15 or large enough (10-20 carrier periods) to ensure good smoothing, or poor smoothing if the filter time constant is selected as minimal (1-2 carrier periods) sufficient to effectively suppress the quadrature component of the input signal.

A known quadrature interference suppressor is known, which 25, like the aforementioned, is constructed according to the demodulator-filter-corrective DC link modulator, but in it the input signal and the reference voltage of the demodulator are increased compared to the reference to reduce the delay introduced by the filter with 30 good smoothing voltage of the modulator frequency [2].

The disadvantage of this suppressor is the need to use a voltage source of high frequency, which greatly complicates its design.

Closest to the proposed correctional suppressor contains a source of co-oscillating voltage, the first and second outputs of which are connected respectively to the first inputs of the demodulator and modulator, the second input of the demodulator is connected through a scale element to the input of the device, and the output to the storage element and the second input of the modulator, output which is connected through the restrictive element to the output of the differentiating element (3].

The disadvantage of this device is the reduction of the differentiation effect (a decrease in the slope of the amplitude-frequency characteristic along the envelope) with a decrease in the ratio of the first time constant

3Θ increments in the amplitude of the input signal 1) input voltage on the capacitor 5 of the differentiating circuit is accepted. The steady-state value and conductivity of the differentiating circuit are determined only by resistor 7, i.e., it is minimal. In the presence of increments in the amplitude of the input signal Ubx, the conductivity of the differentiating circuit increases due to a change in the charge of the capacitor 5 in proportion to the increment speed. The presence of pauses in the voltage supply to the differentiating circuit during non-working half-cycles does not affect its transfer characteristic due to the introduction of key 4, and the logarithmic amplitude-frequency characteristic (LAC) of such a device has a rise of about 20 dB per decade 12 (Fig. 2) , while the known device logarithmic amplitude-frequency characteristic (LAC) has a rise of only about 12 dB per decade 11 (figure 2).

Using the key in the proposed invention improved the quality of its work.

Claims (3)

(54) DEVICE FOR SQUARE QUADRATURPOP The invention relates to automation and can be used in following systems and other automated electric drives. A device for compensating the quadrature component, a demodulator, a smoothing filter, a corrective DC link, a modulator, as well as a source of alternating switching voltage 1, is known. The disadvantage of such a corrective suppressor is the significant delay introduced by the smoothing filter if its time constant is long enough (10-20 carrier periods) to provide good smoothing, or poor smoothing if the filter time constant is minimal (1-2 carrier periods) sufficient to effectively suppress the quadrature component of the input signal. A quadrature interference suppressor is known, which, like the above, is built according to the demodulator-filter-corrective link of a constant tocodulator, but to reduce the delay introduced by the COMPONENT by smoothing the input signal and the reference voltage of the demodulator, a higher frequency than the reference voltage of the modulator 2. The disadvantage of such a suppressor is the need to use a high-frequency voltage source, which greatly complicates its design. Closest to the proposed correctional suppressor contains a source of switching voltage, the first and second outputs of which are connected respectively to the first inputs of the demodulator and modulator, the second input of the demodulator is connected through the scale element to the device input, and the output to the storage element and the second the input of the modulator, the output of which is connected through a limiting element to the output of the differentiating element 3. The disadvantage of this device is the reduction of the differentiation effect (reduction Pull the amplitude-frequency characteristic of the envelope) with decreasing ratio of the first time constant of the differentiating circuit, to the duration of the period Tc of the carrier frequency ,. This is already manifested npvi-t.: ,,. jT Q -ilQO, This is explained by the fact that the capacitor of the dIforponing RC-circuit is discharged by the resistance of the circuit during the non-working half-period when the pulleys of the river is closed, and F is discharged: the smaller the end of the half-period As a result, the conductivity of the differentiating circuit at the zero frequency of the envelope of the input signal increases, as a result of which the differentiation effect decreases, and consequently, the quality of operation of the device deteriorates. The purpose of the invention is to increase the reliability of the device. This goal is achieved by introducing a key into the known device for compensating the quadrature component, the first input of which is connected to the second output of the switching voltage source, the second input to the modulator output, and the output of the differentiating element. Fig. 1 shows a functional diagram of a device for compensating a quadrature component; in Fig.2, logarithmic amplitude-frequency characteristics. The device contains a scale element (resistor) 1, demodulator 2, modulator 3, key 4, differentiating element (capacitor), 5, storage element (capacitor) 6, limiting element (resistor) 7, switching voltage source 8, device input 9 j, device output 10 /. logarithmic amplitude-frequency, device characteristic 11 and logarithmic amplitude-frequency characteristic 12 of the device (FIG. 2). The device works as follows. Demodulator 2, modulator 3 and key 4 are closed alternately with the help of switching voltage from source 8. At half-periods, when demodulator 2 is closed, and modulator 3 and key 4 is open, capacitor 6 is recharged by positive voltage (or negative) half-wave of the input voltage Dgx of the device input 9, and in the differentiating circuit formed by key 4, capacitor 5 and resistivity 7, due to the presence of key 4, there are no currents, and capacitor 5 stores the voltage that was it by the end of the previous half period In those half-periods when demodulator 2 is open and modulator 3 and cell 4 are closed, the voltage of the capacitor is transmitted through the differentiation circuit to the output of the device 10. In the steady state when there is no increase in the amplitude of the input signal and ex voltage on the capacitor 5 of the differentiating circuit takes the steady state value and the conductance of the differentiating circuit is determined only by resistor 7, i.e. minimum. When there are increments in the amplitude of the input signal UBX, the conductivity of the differentiating circuit increases due to a change in the charge of the capacitor 5 in proportion to the rate of increment. The presence of pauses in the supply of voltage to the differential circuit in non-working half-periods does not reflect on its transfer characteristic due to the introduction of the key 4 into it, and the log-amplitude-frequency characteristic (LAFC) of such a device has a rise of about 20 dB per decade 12 (Figure 2) whereas, in the known device, the logarithmic frequency response (LAF) has a rise of only about 12 dB per decade 11 (Fig. 2). Use in the proposed invention, the key has improved the quality of his work. The invention The device for compensating the quadrature component, containing a source of switching voltage, the first and second outputs of which are connected respectively to the first inputs of the demodulator and modulator, the second input of the demodulator is connected through the scale element to the device input, and the output to the storage element and the second input of the modulator, the output of which is connected via a limiting element to the output of the differentiating element, characterized in that, in order to increase the reliability of the device, it is INH key, the first input of which is connected to the second output of the switching source voltage, a second input to the output of the modulator, and the output - to the input of the differentiating element. Sources of information taken into account in the examination 1. Zaitsev GF Correction of automatic control systems of direct and alternating current. M., Energie, 1969, p.45-48, fig.2.1a. 2. Kurakin K.N. Track systems of low power. M., Mechanical Engineering, 1965, p.234, Fig.5.1. 3.Gostev V.N. Suppressors and compensators quadrature interference. K .. Technique, 1971, p.57 (prototype). No.- / four $ m -,  " L to - five -L71 - / 5tkot this / L