SU1206932A1 - Device for controlling self-excited controlled voltage inverter - Google Patents

Description

This invention relates to the field of power conversion technology.

The aim of the invention is to expand the frequency range of the inverter.

Figure 1 shows the functional diagram of the device; in fig. 2 - time diagrams), explaining the principle of its operation.

The assumption is that (the half-cycle of the output voltage of the inverter consists of four clock intervals of the same duration, inside each of which the formation of pulses is made, which constitute the output voltage curve),

The device contains a source of control voltage 1 connected to amplifiers 2 and 3 with normalized and different transmission coefficients. Amplifiers 2 and 3 are connected via switches 4 and 5 to the input of a comparator connected to the distributor 7 of control pulses. The clock pulse generator 8 is connected via a frequency divider 9 to a register 10 connected to control key chains 4 and 5 and to a distributor 7.

The generator 8 is also connected to a sawtooth voltage generator 11 consisting of an integrator 12 connected to threshold elements 13 and 14 connected through an OR 15 element to an inlet plug 16, the output of which is connected to a voltage switch 17, which is connected to the input of the integrator 12. The input signal to the sawtooth generator 11 comes from the generator 8 of the driving pulses to the element OR 1 the output signal of the generator 11 is the voltage of the integrator 12 supplied to the second input of the comparator 6.

The output pulses of the generator 8 (figure 2 q) arrive through the element OR 15 at the counting input of the trigger 16 and cause its periodic operation. The output signal of the trigger 1 6, in turn, contributes to the throwing of the polarity switch 17, the voltage of which, having a stable value, charges the integrator 12.

At the output of the integrator 12, a close to linear output voltage U, is formed, the maximum and minimum value of which is fixed by the threshold elements 13 and 14, the output signals of which flip the trigger 16 between the pulses from the generator 8 (in this case

there are three additional switchings). The sawtooth of integrator 12 is fed to the input of comparator 6, where it is compared, depending on the number of the clock interval, with the constant control voltages of amplifiers 2 and 3 and and Uj (Fig. 2b). At the moments of equality of these voltages, a signal is generated to switch the inverter power vintels, and the fronts of the output voltage curve Ugy are formed (Fig. 2c).

The pulses of the generator 8, which are fed to the input of the register 10, are divided by a divider 9 of the pulse frequency by two. The switching sequence of the clock intervals of the register, made according to the three-bit counter scheme, is shown in Fig. 2 g. At commands from the corresponding outputs of the register, key 4 is closed periodically at clock cycles T, and key 5 is closed at clock cycles T. Coefficient

the transmission of the amplifier 3 is greater than the amplifier 2, so that (figure 2 bv) the duration of the output pulses at central clock intervals is greater than at the extreme,

which contributes to the improvement of the harmonic composition of the output voltage of the inverter with the described shaping algorithm.

The high bit of register 10 is connected to the distributor 7 control pulses, depending on the signal from the output of the high bit register 10 (O or 1) the distributor 7, being the simplest logic device, generates control pulses to the gates, forming respectively positive and negative half-wave output voltage. By increasing

in the output voltage curve of the number of clock intervals, the register size, respectively, is equal to.

Thus, adding a threshold node to a known device, usually implemented on the basis of a comparator, to the second input of which a reference voltage is supplied, RSHI and trigger level circuits with a counting input significantly expands the frequency control range of the output voltage due to a smooth change in the number of pulses in the output crooked. The number of pulses in the output voltage curve can be smoothly reduced from the maximum number at the minimum inverter frequency of the inverter up to one pulse inside each clock. Compiler O. Parfenova Editor H, Pushnenkova Tehred 3. Paliy

Order 8731/57 Circulation 632 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab, 4/5

, - „11-1--. -. Filial PS Patent, g, Uzhgorod, st. Project, 4

1206932

interval at maximum output frequency. The average switching frequency in the inverter power circuit is close to a constant S value.

So, if at the beginning at the initial output frequency within each clock interval the output curve of the inverter is formed by 4 pulses

ca, and the working frequency of the inverter

equal to 20 Hz, then with the same structure of the SI.POVA scheme, the maximum output frequency of the inverter can be increased by about 4 times, i.e., up to 800 Hz, using the proposed control device

Proofreader G. Reshetnik

Claims (1)

DEVICE FOR CONTROLLING AN AUTONOMOUS REGULATED VOLTAGE INVERTER, containing a control voltage source connected to normalized amplifiers connected through appropriate keys to one of the comparator inputs connected to a control pulse distributor, a register whose outputs are connected to control circuits of the corresponding keys, a clock pulse generator , characterized in that, in order to expand the frequency range of the inverter, the device is equipped with a frequency divider, in series with a single polarity switch and an integrator connected to the inputs of two threshold elements, the outputs of which through the OR element and a trigger with a counting input are connected to the input of the polarity switch, the output of the clock generator is connected to the OR element, and the frequency divider is connected between the output of the clock generator and the register input , the high-order output of the register is connected to the control pulse distributor.