SU1508325A1 - Method of controlling series resonance voltage inverter with opposite-current diodes - Google Patents

Abstract

The invention relates to electrical engineering. The purpose of the invention is to increase the reliability of the inverter. The goal is achieved as follows. First, the moments at which the output current of the inverter passes through zero are determined, and at these times a pulse of a duration sufficient to restore the locking bounds of the controlled keys is generated. At the end of the pulse, a spreading reference signal is formed. The control signal is formed by comparing the feedback signal on the output current of the inverter and the reference signal, and is fed to that control key, the forward direction of the current in which coincides with the direction of the output current of the inverter. Since the control signal is generated based on instantaneous values of the output current only, i.e. Inertia-free, and has a guaranteed time to restore the locking properties of the keys, regardless of changes in the parameters of the load, interruptions in the switching of the inverter are eliminated, its reliability is increased. 4 il.

Description

The invention relates to a converter technique and can be used to stabilize the output current of a series resonant voltage inverter operating, for example, in a capacitive storage system (EH) charging system. energy.

The purpose of the invention is to increase the reliability of the inverter when changing load parameters.

FIG. Figure 1 shows a functional inverter circuit for carrying out the proposed method; FIG. 2 shows timing diagrams for explaining the operation of the inverter (where Ug, U, n U, T are the voltages at the outputs of the respective elements, and U, o. I, U , oi, Uni, and 1 ("18-1 voltage at the corresponding outputs of the respective elements); in Fig. 3 - a single-wavelength sequential voltage inverter circuit with countercurrent diodes and a divided switching reactor; in Fig. 4 - time Chart diagrams of the inverter, shown in Fig. 3, in mode

00 od ts5

SP

continuous current (where i, i, i

and/

- currents and

U v- - and. 3

the voltage corresponds to the 01cih elements).

The inverter (FIG. 1) contains a series-1T series-connected source 1.pi7 ani, latching keys 2 and 3, o), which are mounted by diodes 4 and 5, a resonant LC-circuit consisting of a rector 6 and a capacitor 7 variable load 8, sensor 9 of the output current of the inverter, sensor 10 for the current output current, shapers 11.1 and 11.2 pulses of a given duration, element OR 12, sweep generator 13, selector 14 of the inverter output current sensor signal module, the adder 15, the regulator 16, the node 17 of the comparison and the distributor 18 of control pulses,

The inverter (Fig, 1) works as follows.

Current sensor 9. made, for example, in the form of a current transformer, generates a signal proportional to: the instantaneous value of the output current ij of the inverter (Fig. 2a) о Polarity sensor 10 of the output current (SJT) taken, for example, on two single-threshold Comparators with a zero voltage reference generates a signal of a logical unit at its first output with a positive current (Fig. 26); with a negative current direction, a signal of a logical unity is present at the second output (Fig. 2c), thus output signals In the opposite phase, the signals from the PST terminals are fed to the formers 11, and 11.2 pulses of a given duration (PI) are made, for example, according to the circuit of the generator of short pulses on the negative front of the input signal, which are pulses of duration tq

 t ggj-. (Fig. 2d and Fig. 2d) 5 arriving through the OR element 12 to the generator 13 of the sweep voltage (UAH), is made as required; for example, according to the saw-tooth voltage generator scheme. The pulses arriving at the HRN IBs synchronize it by resetting the output voltages of the UAH to zero (FIG. 2e). The signal of the current sensor 9 enters the module 14 module.

The datasrp signal of the output current of the inverter (VM) 5 performed, for example, according to the two-period precision rectifier circuit, From the output of VM 14, a signal equal to the absolute value of the signal signal of the output current of the inverter (Fig. 2g) enters the adder 15 J os; 1 Blocking factor D the variation of the difference between the signal U, the current feedback and the signal, and the job, the adder can be performed according to a scheme, for example, a subtractor amplifier. From the output of the adder 15, the differential signal enters the controller L51TOR 16, made, for example, according to the scheme GO-1-controller. The output of the regulator 16 is fed to one input of the comparison node 17, the second input of which receives a signal from the output of the GRN 13 (FIG. 2e). Comparison node 17 is made, for example, according to the comparator circuit. At the moment of equal voltage of the GDI 13 and V-code voltage of the regulator 16, a logical voltage appears at the output of the comparison node 17, which is fed to the control pulse distributor 18, made, for example, according to the selector scheme, and distributing the pulses arriving at its input from the ID of the comparison node 17 in accordance with the signals of the TMA 10 to the control electrodes, control 1x keys 2 and 3 so that, in the positive direction of the output current, the invert; and investigator but, to the logical unit at the first output of the TFT 10, the turn-on signal is applied to the controlled key 2 (FIG. 2i), and with a negative current direction and logical unit at the second output of the TFT 10, the turn-on signal is fed to the controlled switch 3 (FIG. 2k) . From the consideration of the implementation of the proposed control method using the example of the full-cycle sequential inverter voltage circuit with countercurrent diodes, it can be seen that with any change in the frequency of the output current of the inverter, the turn-on signal is applied to the control switch after at least t d ,,, which eliminates the inverter tipping over,

DL increase reliability and efficiency. ; a series voltage inverter, it is advisable to limit the rate of current rise in the controlled keys. To this end, part number 1

The reactor is connected to the inverter DC circuit. This inclusion of the switching reactor in addition to reducing oli / dt limits the through currents in the keys.

The half-wave diagram of a series inverter with countercurrent diodes and separated by a switching reactor is shown in FIG. 3. Part of the switching reactor may be connected to a constant circuit (reactor 6.2 in FIG. 3), or symmetrically and in series with controllable keys ( reactor 6.3 in FIG. 3)

the pulse duration formed by the pulse shaper of a given duration, it can be concluded that the circuit time for restoring the locking properties of the key is equal.

t

in wasp

 t „+ L,

5 / Ucl,

le

 Voss

flocc

sis ISMOKC sinoJtn

and.,

(one)

The inverter (Fig, 3) works as follows.

Consider the operation of the inverter in continuous current mode. Explanatory diagrams are shown in FIG. A for the case of switching on a 6.3 switching reactor,

Fig. 4a shows the current ig. Suppose that until the moment t | 3 the switch 3 was working. On the interval t, - t, the diode 5 conducts current. At the moment of time t, a control signal is supplied to the controlled switch 2 (FIG. 3). FIG. 46 shows the control current key. The interval t - t corresponds to the transition of the current from the diode 5 of the countercurrent to the controllable switch 2, the reactor 6.3 is connected to the power source. The increase in current on the key 2 occurs according to a law close to linear:

di / dt

where is l

AT

Uj

reactor inductance 6.3,

supply voltage,

The increase in direct voltage on key 3 starts at time t, thus, the current through key 3 stopped at time t, and the direct voltage is applied to the key at time t, assuming that the time interval is to - - t, corresponds to the minimum control angle equal to

 min Wt

 / It with (t, to) w

where (l) is the circular frequency j

five

0

where i

in Mschks

0

five

0

five

0

key current max. Thus, in order to ensure the reliability of the inverter operation with an abrupt change in load, it is necessary to form a pulse with a duration sufficient for the device. development of the locking properties of the key, taking into account the action of inductances included in the DC circuit.

The inclusion of a portion of the switching reactor in the DC circuit reduces the oli / cjt of the switches, limits the through currents and reduces the pulse duration that limits the minimum time between current and voltage without compromising the reliability of the inverter.

Claims (1)

Formula invented the shadows A method of controlling a series resonant voltage inverter with countercurrent diodes made on controlled switches, which determine the instant of the output current of the inverter through zero, generates a control signal equal to the difference between the reference signal and the feedback signal, and compares the control signal with the unwrapping voltage, at the moment of equality of these signals, they form a switching signal of controlled keys, characterized in that, in order to increase the reliability of the inverter, with changes in direction the output current of the inverter stops the switching on signal to the controlled key, at the moment the current passes through zero, the development of the sweep voltage is completed, a pulse of a duration sufficient is sufficient non to restore the locking properties of the controlled key, at the moment of the end of which the sweeping voltages begin to form, determine the directions of the forward current and divide the direction of the output current the inverter after crossing it through zero and give a turn-on signal to that control key in which inverter output current. direct current directions fall and the inverter after crossing it through zero, and give a turn-on signal to that controlled key, in which the directions of the forward inverter output current. 1 P I Ik -  ,, --K „| ,,,. .... sja 9g P Ik. I - ifs.2