Magnetic Phase Shifter Research Articles

Magnetic phase shifter for superconducting qubits.

We have designed and investigated a contactless magnetic phase shifter for flux-based superconducting qubits. The phase shifter is realized by placing a perpendicularly magnetized dot at the center of a superconducting loop. The flux generated by this magnetic dot gives rise to an additional shielding current in the loop and induces a phase shift. By modifying the parameters of the dot an arbitrary phase shift can be generated in the loop. This magnetic phase shifter can, therefore, be used as an external current source in superconducting circuits, as well as a suitable tool to study fractional Josephson vortices.

Method for Linearity Improvement of Magnetic Phase Shifter using Rectangular Wave Source Superposed with Pulse Voltage

Method for Linearity Improvement of Magnetic Phase Shifter using Rectangular Wave Source Superposed with Pulse Voltage

Magnetic control thyristor chopper equipment for battery vehicle

The following three major advantages were observed by adopting a magnetic phase shifter for gate control of a thyristor. 1) A single magnetic phase shifter can compare and amplify multiple signals in an insulated status. 2) At the same time, simplified current detection greatly reduces the number of parts required. 3) It is barely susceptible to the influences of noise. These facts imply that a magnetic phase shifter constitutes a highly reliable and low-cost control device. Especially, using this as a control unit for a chopper offers a substantial advantage with respect to the antinoise margin. By utilizing a balanced half-wave type magnetic phase shifter (capable of operating with a dc power source by combining with a switching transistor), we have developed a gate controller that is free from the influences of noise and allows control of current duties ranging from a minimum value to 100 percent maximum with a greatly simplified circuit.

Magnetically controlled thyristor chopper for Seikan undersea tunnel battery locomotive

We have developed thyristor chopper equipment which is controlled by magnetic phase shifters as the speed control equipment of a battery locomotive for the Seikan Undersea Tunnel. The main feature of this equipment is adoption of a balanced half-wave type magnetic phase shifter, having high reliability together with many functions, in a simple structure to the thyristor gate control. Special consideration was given to the smooth control characteristics at around the minimum and maximum points of the chopper output voltage. This construction of equipment received special consideration regarding its ability to withstand severe working conditions. Satisfactory results were obtained in various performance and reliability tests, and locomotives supplied with this equipment are already operating in excellent condition.

Evaluation of core characteristics of magnetic phase shifters for thyristor amplifiers

The exciting current characteristic is suggested as a new method of evaluating the core characteristic. The phase shifting characteristic and the difference between a positive and negative waveform of a balanced half-wave type magnetic phase shifter are calculated by using the exciting current characteristics of cores employed in it. From these theoretical analyses, it can be determined that the difference of a positive and negative waveform is caused by a difference of exciting current characteristics of two cores used in it, and it becomes larger in proportion to larger control-circuit resistance. An experiment was performed using two pairs of cores, in which one pair of exciting currents are identical and the other pair differ. Theoretical results are in good agreement with the experimental results.