SU782554A1 - Automatic system for maintaining plasma cord - Google Patents

Description

(54) AUTOMATIC HOLDING SYSTEM OF THE PLASMA CORD The invention relates to high-temperature plasma technology and can be used to hold the plasma cord in equilibrium in experimental Tokamak-type thermo-nuclear installations with a copper casing and control windings located outside the copper casing. A known automatic system for holding a plasma cord at the NDALAC unit. The installation is made with an aluminum casing with a control winding located inside the casing. The system consists of a voltage amplifier bias patch, a transistor power amplifier and a power amplifier; control current The control windings and the cord displacement sensor are located inside the case. The power amplifier on transistors to provide the necessary magnitude of the control magnetic field only at the location of the control windings inside the conductive housing, which leads to the complexity of the installation design. An increase in the amplification of the amplifier increases the number of trusts (this leads to the reliability of the device). The plasma pinch retention system is known at the Tokamak installation with a copper casing and control windings located outside the copper casing 2. Two control windings are connected separately to resonant inverters on controlled valves, to the control inputs of which are connected, consequently, forming devices and pulse distributors, connected to separate outputs of the converters An analog signal generator whose common input is connected to the output of a voltage amplifier. A resonant inverter on thyristors makes it possible to obtain currents in the control windings of a semi-sine wave form of the order of ten clocks. The current amplitude is 376 hundred times, the duration of half a heart pulse is also constant, RC parameters determined by the circuit. The process of regulating the average backup of the control magnetic field is carried out by changing the duty cycle of the current pulses in the control winding. Depending on the direction of the cord deflection and, accordingly, the polarity of the voltage of the segvilla, one or the other resonance inverters will work, and the currents in the control windings will create control magnetic fields to compensate for the deflection of the plasma cord. However, in the known device there are disadvantages. When the inverter operates, the current in the control winding is determined by the sum of the voltage of the power source and the voltage of the switching capacitor. If the plasma cord is held in one direction, then the polarity of the direction of the bias signal retains a certain sign and one inverter operates. When the plasma cord changes its direction of motion, the polarity of the direction of the bias signal changes and another inverter starts to work. The first current pulse in the other control winding is determined by the sum of the source voltage and the voltage of another switching capacitor, which may differ from the value of the switching voltage1 of its previous capacitor about the inverter. The disturbance of the regulation process caused by this can be recovered through one or two successive control pulses. With frequent changes in the direction of movement of the cord, the control system's performance decreases. The presence of two main control windings and two additional windings designed to compensate for induced EMF from uncontrolled vertical magnetic fields, while holding the cord horizontally, constructively complicates the installation. The aim of the invention is to increase the speed of the device. For this purpose, in the automatic holding system of the plasma cord to one control winding there are successively connected a resonant inverter and a current polarity switch on controllable valves, to the control inputs of which are connected forming devices connected directly to the 4 separate outputs of the analog signal converter, and sequentially forming devices and a pulse distributor connected to the same outputs are connected to the control outputs of the resonant inverter; ovogo signal. Resonant inverter, nalogic inverter used in prototype | 2. performs the function of regulating the change in the duty cycle of the current pulses in the control winding and differs in that it operates on control pulses, both at a positive voltage of the cord displacement signal, and negative. Another current inverter is used as a current polarity switch | 2 |, in which, instead of the switching capacitor, the control winding is turned on and the current is switched only when the polarity of the voltage of the plasma-cord bias signal is changed. When changing the direction of the plasma cord and, accordingly, changing the polarity of the voltage of the cord bias signal, one resonant inverter is operated, in which the voltage of the switching capacitor is kept as high as required for the control process, and there is no time loss for additional recharging . This ensures the speed of the system. Reducing the number of control and compensating windings in half simplifies the configuration of the installation. Serial connection of the resonant inverter and the polarity switch of the current made on the thyristors protects the system from random impulse noise that may occur in separate circuits of the control units to start the inverter and the polarity switch. The current in the winding control. Only when the control pulses are supplied synchronously both to the current inverter and to the current switch. FIG. 1 is an automatic system diagram; FIG. 2 is a diagram of a resonant inverter and current polarity switch. Plasma cord containment system contains plasma core 1, copper case 2, D (offset voltage 3, integrator .4. Voltage amplifier 5, converter v, 6, distributor 7, inverter generator 8, resonance

Hfiift Inverter 9; Current Forming Device 10; a polarity switch 11, a control winding 12, a switching capacitor 1, a constant voltage source 14, an inverter thyristor 15, 16, and a current switch thyristor 17, 18,

The device works as follows.

When the flame cord 1 is displaced from the stationary position ;, the voltage of the signal of the displacement sensor 3 after the integrator 4 is sensed to the input of voltage amplifier 5. The voltage of the mixing signal after amplification is shown to the input of converter 6, which converts the analog voltage of the signal into a period of pulses starting thyristors of the resonant inverter 9 current polarity switch 11.

Converter 6 has two outputs connected to two control channels. Depending on the polarity of the bias voltage, the pulses are pro; move on one channel or another.

To start the resonant inverter 9, the obo-channels are connected to the distributor 7, which co-divides the number of pulses by two and in turn turns on the forming devices 8 connected to the control inputs of the thyrastors 15 and 16.

During the operation of the automatic system, the distributor and the inverter operate continuously and regardless of which channel passes the pulses Inverter 9, in addition to changing the duty cycle of the current pulses in the control winding, it recharges the switching capacitor 13 necessary for the system to work. The frequency of turning on the thyristors of each group of 15 or 16 is half the frequency of the pulses of the converter 6.

To start the current network switch 11, one channel is connected through.

the forming device 10, to the control inputs of the thy.stors 17, and the other {sanal - through the forming device 10 - to the control inputs of the thyristors 18. The switching frequency of the thyristors of each group 17 or 18 is equal to the frequency of the pulses of the converter 6.

Thus, depending on the polarity of the bias signal voltage, the thyristors of group 17 or group L8 operate and the current in the control winding flows in one direction or in the opposite direction.

Claims (1)

Invention Formula An automatic plasma cord restraint system containing two control windings connected to two resonant inverters on controllable fans, which form the devices, pulse distributors, analog signal converter, so as to improve the speed of the device A resonant inverter and a current polarity switch on controllable gates are connected in series to the control circuit, to whose control inputs are connected forming devices connected to There are several analogue signal converter outputs, and sequentially forming devices and a pulse distributor connected to the same outputs of an aggalo gip converter are connected to the control inputs of the resonant inverter. Sources of Information, taken into account in the examination 1. Anderson X b. Feedback. ControB bor Peobmot ecj, we- (bnum in ormaV / Nuctear Fucsion. (4), 197fc, p-620.