SU1504758A1 - Method of controlling output voltage of a.c. to d.c. voltage converter - Google Patents

Abstract

The invention relates to electrical engineering and can be used to regulate an alternating voltage converter into a constant with a low level of output voltage ripple. The aim of the invention is to simplify the adjustment of the converter due to the independence of the control of the rectifier from the parameters of the active filter. This goal is achieved by the fact that in an AC-DC converter, containing a controlled rectifier 1, an active filter made in the form of an amplifier 3 with an output transformer 4, an active filter is controlled depending on the control error signal. In addition, a signal proportional to the output voltage of the transformer is removed and converted to a second signal proportional to the output voltage component of the converter due to the specified output voltage of the transformer, and then the second signal is summed with the control error signal and, depending on the received signal, controls straightened. 3 il.

Description

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Controller 1, an active filter, made in the form of an amplifier 3 with an output transformer 4, controls the active filter depending on the control error signal. In addition, a signal is taken that is proportional to the output voltage of the transformer and is converted to a second signal, which is proportional to

the output voltage of the converter, due to the action of the specified output voltage of the transformer, and then the second signal is summed with the control error signal and, depending on the received signal, is controlled by the rectifier. 3 il.

The invention relates to electrical engineering, specifically to methods of regulating an alternating voltage converter into a constant, containing a controlled rectifier and an active filter that can be used in converters designed to power the experimental installation 1) and other devices requiring - dich voltage with a low level of voltage ripple, as well as for current control.

The purpose of the invention is to simplify the adjustment of the converter due to the non-dependence of the rectifier control on the parameters of the active filter. : FIG. 1 is a diagram of a constant voltage transformer IB constant, implementing the proposed method; in fig. 2 is a diagram of the additional correction node | naj in FIG. 3 is a block diagram, | explaining the principle of operation of the converter control system | I A variable-voltage converter consists of. level control 1 with system 2 control, active filter, you: filled as amplifier 3 with output transformer 4. To input of amplifier 3. the output of additional regulator 5 connected via adder 6 and corrective circuit 7 signal summation and correction function. One of the inputs of the regulator 5 is connected to the auxiliary winding 8, and the second input is connected to the output of the first regulator 9, which performs the function of signal correction. The input of the regulator 9 is connected to the output of the adder 10, one of the inputs of which is connected to the output of the converter, and the second through the potential isolation node 11 to the source 12 of the reference signal. With system input 2

15

35

20 25

ZO

0

five

controlling the rectifier 1, the potential isolating node 13 is connected to the output of the second regulator 14, which performs the function of summation and correction of signals using the adder 15 and the correction circuit 16. One of the inputs of the regulator 14 is connected to the in, IX of the adder 10, and the second through an additional correction node 17 with the output of the regulator 9.

The additional adjustment unit 17 consists of the proportional link 18 built on the operational amplifiers, the aperiodic link 19, the integrating links 20 and 21 and the inverters 22 and 23.

The method is carried out as follows.

The output voltage of the converter (Fig. 1) can be represented as the sum of the components, due to the action of the EMF of the rectifier, equal to EP, and the output voltage 4e of the transformer. Suppose that the relationship between the emf is higher than the emulator and the output voltage component,. due to this EMF is determined by the transfer function V, (B), a. the connection between the output voltage of the transformer and the resulting component of the output voltage, the transfer function W (). Then, for the converter, it is possible to present the block diagram shown in FIG. 3, in which Wp, (S) expresses the transfer function of the first regulator 9, Wp (S) is the resulting transfer function of the regulator 14 and rectifier 1, and W. ( S) is the transfer function of the correction unit 17. The inclusion of the controller 5 and the introduction of feedback through the additional winding 8 provides a sufficient bandwidth, thanks to

P which in the required frequency range is proportional to the connection between the signal at the input of the regulator 5 and the output voltage of the transformer (in connection the parameter of the amplifier is presented in figure 3 as the gain factor K.) Thus, the input of the corrective node 17 the signal is proportional to the output voltage of the transformer, resulting in the input element with the transfer function Wp (S), i.e. to the input of the regulator 9 in the control channel of the active filter, an adjustment error signal is sent, which is the difference between the actual value of the output voltage U g and its set value Uj, and the input of the element with the transfer function W pj (S), t . The input of the corrective circuit 16 receives a signal equal to the sum of the output signal of the corrective node 17 with the transfer function W (S) and the control error signal. Controller independence is independent of the active filter parameters, providing easy setup of the converter, provided that the transfer function W (S), which determines the connection between the target signal Uj and the signal and d, when the control loop is open at point A (FIG. 3), is

W (S)

Wpa (S) Hi

(S)

In turn, this equality is fulfilled if the ratio

W (S) -KW, (S),

those. provided that the corrective node 17 converts the signal applied to its input, which is proportional to the output voltage of the transformer, to a signal that is proportional to the component of the output voltage of the converter, which is caused by this voltage. The physically stated position is explained by the fact that at the indicated parameters the signal attenuation, due to the formation of a closed feedback loop in the active filter circuit, is compensated by the gain in parallel channels: the job input is the input of the second regulator and the job input is the first regulator - Additional compensation10

15

20

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thirty.

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40

45

50

55

This device is the input of the second controller.

The additional correction node 17 is an analog model of transformer A load, the parameters of which are determined by the passivity of the filter and the load of the converter. Proportional link 18 reproduces the connection between the OUTPUT voltage of the transformer and the voltage Uj; on the passive filter capacitor and the load voltage. Aperiodic link 1 9 determines the connection between voltage and load current. Integrating link 20 defines the connection between current and voltage on the filter capacitor, and integrating link 21 between current and voltage on the filter inductance. Thus, The additional correction unit 17 introduced into the converter transforms the signal proportional to the output voltage of the transformer, and the signal proportional to the component of the output voltage due to the specified output voltage transformer in accordance with the condition W (S) KW (S). At high voltages of the power section of the circuit, the potential isolation nodes 11 and 13 provide the potential isolation necessary for the safe operation of the converter during its operation.

The use of the proposed method simplifies the adjustment of the regulators in the variable voltage to constant voltage converter, since the transfer coefficient of the rectifier control circuit does not depend on the mode of operation of the active filter.

Claims (1)

Invention Formula The method of regulating the output voltage of the variable voltage converter into a constant voltage, containing a controlled drive and an active filter, made in the form of an amplifier with an output transformer, connected in series with the load, consisting of forming a reference signal, measuring The output voltage of the converter is subtracted from the reference signal, thereby generating an control error signal, then the resulting control error signal converts the output voltage of the active filter, which is - Qc in that in order to simplify the adjustment of the transducer due to the independence of the control vtr DC converter from the active filter parameters, generating a first signal proportional to the output voltage of the active filter, and it is converted into a second signal proportsional15047588 The output signal of the converter, determined by the specified output voltage of the filter, is summed with the control error signal, resulting in a third signal, then the third signal is converted into a rectifier control signal.