SU650201A1 - Device for control of m-phase power-diode converter - Google Patents

Description

one

The invention relates to a valve converter technique and can be used to control a valve converter when operating on a motor as a permanent or an alternating current.

A device for controlling a three-phase valve converter is known, which contains in each of the p-channel sources of a cosine or sawtooth-shaped reference signal and a comparison circuit generating a control pulse when the reference signal and the reference signal 1 are equal.

The disadvantage of the known device is the deterioration of accuracy and speed in the area of intermittent load currents, where the transfer characteristic of the converter is highly non-linear.

A device for controlling a converter is known, which contains a source of a reference signal, a source of signal proportional to the emf of the load of the converter, a controller whose parameters are changed in the function of the control signal or in the function of the load current 2.

The disadvantages of the known device are as follows.

The use of feedback to change the parameters of the regulators as a function of the load current leads to a delay in

self-tuning discrete control system VP. The change in the parameters of the controller in the function of the controller -stressing the lis roughly linearizes the dependence

load current from the reference signal, since the average value of the load current in a discontinuous mode is complex depending on the control angle and back emf.

The closest solution to the technical essence of the invention is a device for controlling the converter {3, in which the control voltage, rather than the control signal, is corrected.

In addition to the source of the main reference (cosine) signal, it is provided with a source of an additional sinusoidal reference signal, which has the same dependence in time as the average

the value of the ripple of the load current from the angle of control, both of these sources through an adder connected to the circuit.

A disadvantage of the known device is that it does not provide high accuracy in a discontinuous mode, where the dependence of the load current on the steering angle is more complex.

The aim of the invention is to increase

the accuracy of the signal processing task. For this, a device for controlling a t-phase valve converter containing, in each of the W-channels, the source of the main reference signal, the source of the additional sinusoidal reference signal, the main adder — and the comparison unit, is fully equipped with two adders, the source of the signal proportional to the load EMF of the converter, the source a signal that is prolortional to the voltage supply of the output phase of the converter, a non-linear converter with a transfer coefficient depending on the polarity of its input and two diodes, while the source of the main reference signal and the source of the signal proportional to the load EMF of the converter are connected to the input of the first additional adder, the output of which is connected to the nonlinear converter, the specified source of the additional reference signal and the output of the non-linear converter are connected to the inputs of the main the adder, to the input of the second additional adder connected a signal source proportional to the emf load of the converter, and the signal source prop Rational power supply of the output phase of the converter, the outputs of the main and second additional adders are connected to the same terminals of two diodes, the other outputs of which are combined and connected to the comparison unit, in addition, when used as sources of current source signals, the input of the main adder is also included signal source inverse to the output of the second additional adder. FIG. 1 shows the proposed device, functional block diagram; FIG. 2 - the same block diagram of the device when used as sources of signal sources of current; in fig. 3 - diagrams explaining the operation of the control device (Fig. 1) contain the source 1 of the additional reference (sinusoidal) signal, the source 2 of the main reference (cosine) signal, the source 3 of the signal proportional to the load EMF of the converter, the source 4 of the signal proportional to the voltage supplying the output phase of the converter, the source 5 of the reference signal, the first, second and third adders 6, 7, 8 respectively, a nonlinear converter 9, diodes 10, 11, the comparison unit 12. The device (Fig. 2) additionally contains the torus 13, the sources 14, 15 of the signals inverse to the signals of the sources 3 and 4, the adder 16. The device (Fig. 1) works as follows. 6 The output of the first adder 6 is proportional to the difference between the main reference signal and the load emf (/ base), since the feedback signal for the emf is input with the opposite sign (-EO). Until i (Fig. 36), the signal (/ axis - Eo) is positive, and after that moment - negative. The output voltage of the nonlinear converter, whose transmission coefficient depends on the polarity of its input signal, is (/ axis-- o) before ti and ki (/ UN-EO after ti (Fig. 36), because at time ti the signal ( / o) changes its sign and the transfer coefficient of the nonlinear converter (in this case, from 1 to fei) changes. The output of the nonlinear converter is summed in the second adder 7 with an additional reference (sinusoidal) signal / apt and fed to diode 10. The diode 11 receives a signal from the output of the adder 8, equal to kz (where k is transfer efficiency of the adder 8. The signal from the combined pins of diodes 10 and I enters the comparison block 12 and represents the resulting reference signal (/ op) 2. It is equal to the largest of the two input signals of the diodes 10 and I (with positive logic - the most positive signal , and with negative logic, i.e., with the opposite polarity of all signals and the reverse switching of the diodes, the most negative signal). Consequently, until the moment i (Fig. 36) (/ op) 2 is (/ add + / base) in the interval (/ op) 2 / add-H1 (/ ron-- o), and after the time tz ( (op) 2 H2 () It is known that during the transition from continuous mode to continuous adjustment, the converter characteristic undergoes a fracture, and the dependence of the average load current on the control angle in the discontinuous mode is approximately expressed by a cubic parabola. This dependence is shown by the dotted line connecting the points ab-b (Fig. 36), and is rather closely iproxied in the system under consideration. The transmission coefficients of the nonlinear converter 9 (i) and the adder 8 (2) are selected from the best approximation condition. The control pulse is generated by the comparison circuit 12 at the moment of the equality of the signal of the reference 4 and the resulting reference signal (/ oii) S (moment, figure 2). The current pulses formed in the load (Fig. 3b) have an average value / ner that corresponds to the reference signal / s. In this control device, in a wide range of EMF of the load of the converter, the characteristics of the continuous and intermittent modes are clearly de-asserted, since at the limit of the maximum-continuous mode (control angle "mon and point 6, fig. 36)

the resulting reference voltage is equal to "o / apt, which is proportional to the maximum-continuous current at a given angle of control" pi; a clear fixation of the zero value of the resultant reference voltage at those control angles (oskr, Fig. Pros, b) at which the average current value is zero; The approximation of the dependence of the average value of the load current on the angle of control in a discontinuous mode is quite close.

This allows, with a wide range of EMF load for the converter, it is sufficient to accurately approximate the transfer characteristics of the converter and to linearize the dependence of the load current on the reference signal, which improves the accuracy of the reference signal. This device performs a software correction, which is almost instantaneous. Therefore, high accuracy is provided in the dynamics, i.e. at variable steering angles.

In the case of using diodes 10 and 11 as sources of the signal sources of the current sources, they function as a circuit, and therefore the input of the second adder (Fig. 2) additionally includes a signal source inverse to sources 3 and 4.

Thus, in the proposed device, the accuracy of setting the signal of a task in an intermittent mode is increased in a wide range of EMF load and at AC control angles.

Claims (3)

1. A device for controlling a t-phase valve converter containing in each of the t-channels a source of a primary reference signal, a source of an additional sinusoidal reference signal, a main adder and a comparison unit, characterized in that, in order to increase the accuracy of the reference signal in the intermittent mode it is additionally equipped with two adders, a source of signal proportional to the emf of the load of the converter, a source of signal proportional to the voltage of the output phase of the converter, n A linear converter with a transmission coefficient depending on the polarity of its input signal and two diodes, while the source of the main reference signal and the source of the signal proportional to the load EMF of the converter are connected to the input of the first additional adder, whose output is connected to a nonlinear converter, the specified source of the additional reference signal and the output of the nonlinear converter are connected to the inputs of the main adder, to the input of the second additional adder The source of the signal proportional to the emf of the load of the converter and the source of the signal proportional to the supply voltage of the output phase of the converter are indicated, the outputs of the main and second additional adders are connected to the same terminals of two diodes, the other terminals of which are combined and connected to the comparison unit. 2. The device according to claim 1, characterized in that when using sources of currents as sources of signals, the source of the drive is added to the input of the main adder, relation to the output of the second additional adder. Sources of information taken into account in the examination 1. Dynamics of DC valve electric drive. Ed. A. D. Pozdeeva, M., “Energie, 1975, p. 8-14. 2. US patent number 364895, cl. 318-331, 1975. 3. For the number 2143685, cl. H 02Р 13/16, 1975, according to which the positive is accepted decision on issuing auth. St.