Patent EA-019111-B1 (EA)
Title: Pulse step modulator
Inventor: KONOVALOV SERGEJ IVANOVICH
IPC: H02M7/10
Filed: 2011-08-23
Abstract: The invention relates to high-voltage power sources and can be used for generating on load stabilized by amplitude voltage pulses of rectangular or stepped waveform in a wide range of alteration duration and frequency of forming pulses. The claimed pulse modulator is aimed at improving reliability thereof during its operation due to lesser fault probability of switches and diodes caused by overvoltage and also due to the use of two regimes of voltage stabilization on load, ability to provide on load stepped voltage with different envelope shape and at reducing losses during recharging load capacitance. The pulse step modulator comprises a controllable AC voltage source series connected to a transformer having N secondary windings, each secondary winding is connected to a rectifier and forms N series connected modules, the positive terminal of each rectifier is connected to series connected first control switch and to a diode, shunted by a second control switch, diode anode is connected to the negative rectifier terminal, diode cathode of the first module is connected to the diode anode of the second module, the diode anode of the first module is connected to the first load terminal, the diode cathode of the last module is connected to the second load terminal, each of N voltage transducer is connected by its first terminal to the rectifier positive terminal, an output of voltage transducers from 1-st to (N-1) modules is connected to the first terminal of summed device via third control switch, voltage transducer output of N module is connected to the first input of the summed device directly, second input of the summed device is connected to output of the driving voltage source, the output of the summed device is connected to the control input of the AC source, module switches and a third control switch are controlled from generator of control pulses. A limiter voltage is introduced into each module connected between positive and negative terminals of the rectifier, and a protective diode connected in parallel to the first control switch and connected by its cathode to the positive rectifier output, in each module a second input terminal of the voltage transducer is connected to the negative rectifier terminal, the driving voltage source has a control input, the generator of control pulses has (2N+1) output terminals, wherein the first N output terminals of the control pulses generator are connected to control inputs of first switches according to modules numbers, second N output terminals of control pulses generator are connected to control inputs of second switches according to modules numbers, an additional output terminal of the control pulses generator is connected to a control input of third switch and to the control input of the driving voltage source. Each module can be additionally provided with a DC power source connected in series with parallel connected diode and second control switch, wherein the positive terminal of the DC power source is connected to a diode cathode, and negative to anode of the protective module diode and diode anode of next module. Anode of the first module diode can be connected to a first load output via an additionally introduced DC bias voltage connected by its positive terminal to the first load output, and between the anode of first module diode and second load output a bias resistor is additionally provided. A condenser or parallel connected condenser and a protection device with a nonlinear voltage-current characteristic can be used as a limiter.