Abstract: A motor drive system for selectively supplying a drive current to a multiple phase motor having each phase winding divided into a plurality of discrete windings includes a plurality of H-bridge drives to control the polarity and magnitude of the drive current. Each H-bridge drive include a pair of half bridge drives interconnected to the terminals of each of the discrete windings. Each of the half bridges have an upper bridge switching element and a lower bridge switching element for coupling the positive and negative potential, respectively, of a DC power source to each discrete winding. The discrete windings of each phase winding are coupled in series by a plurality relays which are selectively actuated by a controller to interconnect the discrete windings in predetermined groups dependent upon the shaft speed of the motor.

Abstract: A magnet carrier assembly for holding and carrying a high-energy-product permanent magnet is arranged for releasable attachment to a rotor of an axial disc or drum type rotor in an electric machine. The permanent magnet placed in a container which then receives a cover. The magnet carrier assembly includes a mounting flange at one end and a locating and mounting tab at an opposite end for attaching the assembly to the rotor. In certain applications, the rotor has recesses which have a size and shape complementary to the size and shape of the magnet carrier assembly. The recesses are circumaxially located around the radial periphery of the rotor at the poles of the rotor. In other embodiments, the magnet carrier assembly includes a key which is received in a mating groove in a rotor surface and is used to transfer to the rotor the electromagnetic shear force developed by the high-energy-product permanent magnet.

Abstract: A magnet carrier assembly for holding and carrying a high-energy-product permanent magnet is arranged for releasable attachment to a rotor of an axial disc or drum type rotor in an electric machine. The permanent magnet placed in a container which then receives a cover. The magnet carrier assembly includes a mounting flange at one end and a locating and mounting tab at an opposite end for attaching the assembly to the rotor. In certain applications, the rotor has recesses which have a size and shape complementary to the size and shape of the magnet carrier assembly. The recesses are circumaxially located around the radial periphery of the rotor at the poles of the rotor. In other embodiments, the magnet carrier assembly includes a key which is received in a mating groove in a rotor surface and is used to transfer to the rotor the electromagnetic shear force developed by the high-energy-product permanent magnet.

Abstract: A resonant recovery circuit operates to discharge switching energy losses stored in a snubber capacitor associated with each pole of an inverter to return the discharged current to the DC supply by means of an inductor coupled to the resonant recovery switch. In a multiple pole inverter, the snubber capacitors associated with each of the pole's switching devices is sequentially discharged during the clock cycle of the switching frequency. A plurality of recovery circuits may be used in a multi-phase inverter.

Abstract: A four quadrant unipolar pulse width modulated (PWM) power conversion circuit for supplying a desired current to an inductive load uses an H-bridge circuit topology with an upper and lower pair of switching elements including a diode in parallel with each of the switching elements to provide a current path from the load to the power source when its respective switching element is non-conductive. A control algorithm generates switching element control signals to cause the instantaneous voltage across the load to alternate between a single polarity voltage and zero for a portion of the output load waveform to cause the average value of the load current to correspond generally with the desired average load current.

Abstract: A low impedance interconnection assembly for use with high frequency switching power semiconductor devices includes a low inductance modular capacitor, multi-layer planar bus structure and semiconductor switching devices assembled as a laminated unitary structure. Terminals electrically and physically connect the positive electrode of the modular capacitor to the positive DC voltage potential carried by the bus structure and the positive DC input of the semiconductor switch and other terminals electrically and mechanically couple the negative electrode of the modular capacitor to the negative DC voltage potential layer of the bus structure and the negative DC input of the switching device. The low inductance modular capacitor is made of a number of capacitor elements having their respective positive electrodes bonded to a copper foil pattern strip to define a positive electrode and their respective negative electrode terminals to a second copper foil strip to define the negative electrode.