Disclosed is a three phase AC power regulator using a single power modulating element. The element may be operated class A or in switching mode. A transformer primary is connected in Y configuration with the common junction being made through a 6 diode bridge and the single control element. The single control element thereby controls the common current in all three sections of the transformer primary. The transformer secondary windings are coupled to a second 6 diode bridge to produce a DC voltage level which is fed back to drive the control element.
A PWM based converter including a Y-.DELTA., Y--Y transformer (or a .DELTA.--.DELTA., .DELTA.-Y transformer) wherein the Y-.DELTA. portion of the transformer phase shifts input voltage by 30.degree. with respect to the Y--Y portion of the transformer and thereby eliminates many low order supply line harmonics. The rectifier also includes two series connected PWM switching rectifiers, one rectifier receiving input voltages from the Y--Y portion of the transformer and the other rectifier receiving input voltages from the Y-.DELTA. portion of the transformer, and a controller for controlling the first and second rectifiers so as to eliminate low order harmonics on the supply lines that are not eliminated by the transformer. A capacitive bank is required between each rectifier and the transformer.
There is disclosed an alternating current to direct current static converter which includes a three-phase transformer interconnected with two rectifier bridges to produce a twelve-phase connection for direct current output. The twelve-phase connection is provided by coupling input terminals of one of the bridges to corresponding primary input terminals of each of the three phases of the transformer, and coupling input terminals of the other of the bridges to corresponding phase terminals of the secondary of the three-phase transformer. The outputs of the rectifier bridges are then coupled to provide the DC output. The transformer is constructed such that there is a 150 degree phase shift between the primary and secondary voltages of each phase of the three-phase transformer and a 30 degree phase shift between the input voltages to the rectifier bridges.
A regulated power supply system is disclosed including a source of unidirectional electric current, and at least one switch device including a saturable reactor controlled between a saturated condition and an unsaturated condition in a duty cycle such that the load voltage tends to remain constant with varying load current. In one embodiment, a pair of switch devices are coupled, respectively, between the ends of a center-tapped secondary winding of a transformer having a primary winding fed from an inverter, and a pair of rectifier devices coupled to provide the unidirectional current to the load. Control of the switch devices is effected by applying an appropriately varying control voltage to like electrodes of respective inverted control diodes each coupled to the junction between a respective switch device and its associated rectifier device. The control diodes are driven from the output of a comparator amplifier responsive to the difference between the load voltage and a reference voltage. A pulse modulator fed by the amplifier output provides the control diodes with pulses of appropriate varying duty cycle.
In a transformer power supply, a full wave rectifier is series connected in circuit with the primary winding of the transformer such that the current flowing through the primary winding of the transformer flows in series through the input of the full wave rectifier. An inductive load is connected across the output terminals of the full wave rectifier such that the rectified output current flows through the inductive load. The full wave rectifier preferably uses silicon controlled rectifiers which are phase triggered in such a manner so as to control their conduction angles so as to control the power flow from the source to the load connected to the secondary of the transformer. The inductance of the load for the rectifier preferably exceeds the critical inductance so as to minimize ripples in the secondary of the transformer. This type of power supply circuit is particularly useful for supplying power to an electron gun which is subject to arcing. The inductive load for the rectifier reduces the transient voltages impressed on the transformer resulting from SCR phase control and also minimizes AC voltage drop across the inductive load while providing transient current limiting as may be encountered by arcing of the electron gun.
A high power D.C. supply regulated for constant output power to be dissipated in varying loads such as encountered in cathode sputtering systems. A.C. input power is rectified to produce the desired D.C. The output D.C. voltage and load current are measured and a voltage signal proportional to their product is compared with a D.C. input control signal. The comparator "error" output signal controls a pass element that varies a D.C. current through saturable reactors in the A.C. input power lines to regulate the D.C. power into the load. The supply includes a limiting feature that is adjustable to a desired threshold level for limiting D.C. output power, voltage, and/or current so that the limiter will take control from the comparator to hold the supply output at a safe level.
