Abstract: A generalized method for balancing paralleled power converters is disclosed wherein (N) power converters, generally voltage amplifiers, are parallel and have current sensors positioned so as to form a differencing equation for the circulating current, and use that difference current as feedback to the paralleled power converters to force the circulating current to zero. The current sensors are current transforming transducers, where (N−1) transducers are included and where the feedback from the (N−1) transducers is distributed to summing amplifiers, which according to their gain distribution, balances the power converters. The system also includes passive magnetic devices to facilitate current sharing, where the devices are generally inductors which are designed to store no magnetic energy when under balanced excitation.

Abstract: A closed loop Hall effect current transformer in which the Hall effect device has an input resistance which varies with its operating temperature. The Hall effect device is driven by a fixed voltage passing through a current limiting a resistor with variations in voltage across the resistor being indicative of the operating temperature of the device. Further, variations in the input resistance of the device caused by variations in its operating temperature is corrected for by mixing a correcting signal with the outputted signal from the device, said correcting signal being derived from a voltage signal taken across the resistor at the driving input of the device.

Abstract: A dual mode gradient coil system in which amplifiers powered by a single signal source are connected by a switch to a plurality of coils. The switch selectively serves to place the coils in series with said amplifiers placed in parallel for a high change in magnetic field per unit distance or, alternatively, to allow each coil to be driven by a separate amplifier for a high change in magnetic field per unit time.

Abstract: A power supply for supplying a DC voltage from an AC supply voltage provided by an AC voltage source to an amplifier includes a plurality of input lines coupled to the AC voltage source a rectifier coupled to the input lines to provide an unregulated positive DC voltage component and an unregulated negative DC voltage component, first and second regulators coupled to the rectifier and generating controlled positive and negative DC voltage components, and a plurality of output lines coupled to the regulators. The regulators augment the unregulated positive and negative DC voltage components with the controlled positive and negative DC voltage components to create positive and negative DC voltages on the output lines.