摘要:
A voltage converter system includes a first DC-AC voltage converter that converts a first DC voltage signal to a first AC voltage signal. A DC link converts the first AC voltage signal to a second DC voltage signal. A second DC-AC voltage converter converts the second DC voltage signal to a second AC voltage signal. In another configuration a DC-AC voltage converter converts a DC voltage signal to a first AC voltage signal. An AC-AC voltage converter converts the first AC voltage signal to a second, lower-frequency AC voltage signal. In yet another configuration a first voltage converter portion converts a DC voltage signal to pulses of DC voltage. A second voltage converter portion converts the pulses of DC voltage to a relatively low-frequency AC voltage signal. The voltage converter system is selectably configurable as a DC-AC voltage converter or an AC-DC voltage converter.
摘要:
A current source inverter (1) comprises a bridge circuit (2) having a plurality of bridge paths (5), in each of which a controllable power semiconductor component (6) is arranged. In the case of such an inverter, a loss in performance on account of inductance-dictated overvoltages during the turn-off of the power semiconductor components (6) is avoided by virtue of the fact that the controllable power semiconductor component (6) is avalanche-proof at least under loading in the forward direction.
摘要:
A power converter device including a plurality of self-commutated voltage type converters each connected to a common dc circuit, a plurality of transformers each having dc windings and ac windings, each of the dc windings being connected to an ac output terminal of a respective one of the converters and each of the ac windings connected in series, an ac switch through which the serially connected ac windings of the transformers are connected to utility power systems, a capacitor provided in the common dc circuit, a dc overvoltage suppression means installed in the common dc circuit, and a current limiting device, wherein the capacitor in the common dc circuit is charged through the current limiting device means before starting the self-commutated voltage type converters, and the dc overvoltage suppression means is then connected to the common dc circuit and removed after the self-commutated voltage type converters are started.
摘要:
An ozone generating apparatus comprises a rectangular waveform current feeding device for feeding rectangular waveform alternating current between discharge electrodes of a discharge tube of an ozone generator so that a constant current is fed by the rectangular waveform current feeding device during a half cycle period to the ozone generator which is equivalent to a capacitor. Accordingly, the voltage applied to the ozone generator has a waveform which changes in proportion to the time period. Such a voltage waveform is ideal for the ozone generator to improve the conventional ozone generating apparatus.
摘要:
In an inverter apparatus including a plurality of parallel branch circuits connected across a D.C. source, each including a pair of serially connected controllable switching elements, and a plurality of semiconductor elements connected in parallel opposition with respective switching elements, a D.C. reactor is connected on the D.C. side or A.C. side of the inverter and a circuit is connected across the D.C. reactor for preventing attenuation of the current flowing through the D.C. reactor during the OFF period of the switching elements. A source of control pulses is provided for rendering ON respective controllable switching elements each for a 120.degree. interval of the output alternating current. The source of control pulse includes means for chopping the current flowing through each controllable switching element at a predetermined modulation frequency for the former or latter 60.degree. of the 120.degree. interval.
摘要:
A gate controlled thyrister (SCR) used for switching at high frequency for induction heating is supplied with a negative bias during an interval ranging from the point where the forward current reaches to zero to the time of reapplication of a subsequent gating signal. This provides high dv/dt (the rate of rise of anode voltage) capability and small turn off time to the device.
摘要:
The disclosed circuit comprises a thyristor, a diode connected across the thyristor with the opposite polarity, and a commutation capacitor connected across the thyristor through a primary winding of a saturable transformer. The transformer responds to a load current flowing from the thyristor through its secondary winding to produce a reverse current for the thyristor to turn it off. Also there is disclosed the application of the circuit to uni- and bi-directional power control systems.
摘要:
A compact solid-state power supply system for rotating anode Xray tubes. The system includes an AC-to-DC solid state power converter which drives an inverter oscillator using silicon controlled rectifiers. The system provides means for operating the rotating X-ray tube anode at either low or high speeds with automatic braking when going from high speed to low speed. Means are also provided for automatically restarting the system in the event of paralysis of the inverter oscillator. Further, through the use of a novel programmed two-step driving signal, the desired operating speed is reached in a fraction of a second. The unit is compact and lightweight for optimum ease of installation.
摘要:
A device for controlling the current supply to inductive loads through the use of a battery and d.c. pulse transformers associated with each load. Each of the d.c. pulse transformers are controlled from a central impulse generator so that at least the energization point of each of the d.c. pulse transformers are always shifted with respect to those of the remaining d.c. pulse transformers. The d.c. pulse transformers are conventional and can be controlled by the impulse generator for time shifting each at a predesignated time in the period so that the return energy from one load is absorbed by a different load.
摘要:
Herein disclosed is an induction heating equipment having a self-exciting chopper type inverter unit having a combination of a silicon controlled or otherwise gate-controlled rectifier and a diode connected in parallel to a d.c. power source for generating heat in a material to be heated through creation of eddy current and hysteresis losses in the material by building up a changing magnetic field induced by a current having suitable frequencies. Protective means are provided in such equipment so that the inverter unit, especially the silicon controlled rectifier of the unit, is protected from incurring a damage when the inverter unit is to be actuated or in the event an unusually increased voltage is produced in the inverter unit during operation. A typical application of the equipment is a cooking equipment using the induction heating process.