Abstract: A snubber circuit to mitigate voltage overshoot in a power train for driving a motor, the snubber circuit configured to be connected to the motor terminal between a transmission line from a power supply and converter and a motor. The snubber circuit includes a rectifier, a capacitor connected across an output of the rectifier and a load connected across the capacitor. The capacitor is rated to charge to a predetermined link voltage and wherein an input voltage to the rectifier that exceeds the link voltage causes the voltage at the motor terminal to clamp to the link voltage and for excess energy from the input voltage to be stored in the link capacitor and dissipated by the load.

Abstract: An EMI filter arrangement includes a noise source, an input filter connected to the input of the noise source, and an output filter connected to the output of the noise source, the noise source, input filter and output filter provided in an electrically conductive electronics box, and an input filter capacitor electrically connecting the input filter to the electrically conductive electronics box and an output filter capacitor electrically connecting the output filter to the electrically conductive electronics box; the arrangement characterised by further comprising an intermediate reference plane provided in the electrically conductive electronics box, and an intermediate capacitor provided in the electrically conductive electronics box electrically connected between the intermediate reference plane and the electrically conductive electronics box, the input filter capacitor and the output filter capacitor being electrically connected to the box via the intermediate reference plane and the intermediate capaci

Abstract: A series resonant power converter, comprising: a first plurality, m, of resonant power converter modules, each comprising a switching stage, a resonant tank, a transformer, a rectifier stage and an output capacitor, the plurality of resonant power converter modules connected in series across a power supply, the resonant power converter further comprising a common output stage (500) connected across the series-connected plurality of resonant power converter modules, whereby a second plurality, n, of output levels at the common output stage.

Abstract: An active electromagnetic interference filter comprising an adjustable shunt impedance circuit, the adjustable shunt impedance circuit comprising a noise sensing branch that senses input noise and provides a noise voltage representative of the sensed noise, and an operational amplifier stage configured to generate, at an injection branch, an injection current based on the noise voltage.

Abstract: A motor drive system includes an input portion arranged to receive a DC input voltage across first and second conductors. An inverter is connected across the first and second conductors, and is arranged such that, in a normal mode, the inverter receives the DC input voltage and generates an AC drive voltage. A motor is connected to the inverter and is arranged such that, in the normal mode of operation, the motor receives the AC drive voltage. A first normally-open switch is connected along the first conductor between the input portion and the inverter. A damping controller comprising a second normally-closed switch and a damping means is connected in series between the first and second conductors. When the operated in the normal mode, the first switch is closed and the second switch is open. In a damping mode, the first switch is open and the second switch is closed.

Abstract: A method for monitoring insulation in a motor drive circuit configured to convert DC power from a power source to AC power to drive a motor. The method includes boosting a DC link voltage of an inverter of the motor drive, isolating the motor drive circuit from the power source; performing at least one isolation test by providing a current path through components of the motor drive and preferably a motor connected to the output of the inverter to be tested; and monitoring the current during each isolation test to detect partial discharge or excessive leakage from the current path, thereby indicating that there exists defects in the insulation in the current path.

Abstract: An AC-DC power converter includes a bridge circuit that has a first phase leg with first and second power switches connected to each other in series, a second phase leg with third and fourth power switches connected to each other in series. The first phase leg and the second phase leg are connected to the each other via a bridging connection to form the bridge circuit. The converter also includes means for providing power to said bridge circuit, and means for measuring an output voltage of said bridge circuit.

Abstract: A system for providing electric motor control to a plurality of motor loads. The system comprises a plurality of motor controllers that are configurable into different arrangements of motor controllers. The system further comprises a central controller that is operable to individually set a phase and/or frequency of respective PWM carrier signals for the motor controllers, wherein the central controller is configured to set the phase and/or frequency of the PWM carrier signals for the motor controllers within a respective arrangement of motor controllers differently depending on the configuration of the motor controllers within the arrangement.

Abstract: A compensator circuit for a PWM active rectifier includes a look up table containing compensating voltage values for given values of input phase current and input voltage frequency, and a low pass filter arranged to filter the input phase current to the rectifier based on a filter bandwidth determined according to the input voltage frequency. The compensator circuit arranged to receive measured input current and voltage frequency values and to output corresponding compensation voltage values from the look up table, the compensation voltages to be provided, in use, to the rectifier to adjust the switching pattern of the rectifier.

Abstract: An EMI filter arrangement includes a noise source, an input filter connected to the input of the noise source, and an output filter connected to the output of the noise source, the noise source, input filter and output filter provided in an electrically conductive electronics box, and an input filter capacitor electrically connecting the input filter to the electrically conductive electronics box and an output filter capacitor electrically connecting the output filter to the electrically conductive electronics box; the arrangement characterised by further comprising an intermediate reference plane provided in the electrically conductive electronics box, and an intermediate capacitor provided in the electrically conductive electronics box electrically connected between the intermediate reference plane and the electrically conductive electronics box, the input filter capacitor and the output filter capacitor being electrically connected to the box via the intermediate reference plane and the intermediate capaci

Abstract: The present invention relates to a system and method for the monitoring and detection of insulation degradation in electric systems. The system comprises a controller for an electric motor (3), including input circuitry (2a) for connecting the controller to a power supply (1), power conversion circuitry (2b) for providing a power output for the electric motor (3), and sensing circuitry (2c) for monitoring a current inside the controller that is representative of a return leakage current from the electric motor to the motor controller. A condition of the insulation may be determined based on the monitored current.

Abstract: A short circuit detection system and method that identifies a short circuit between turns of a winding of a permanent magnet machine having a three-phase winding in response to detection of imbalances between the three motor phases at an instant in time. The imbalances are identified by monitoring motor terminal voltages and currents.

Abstract: A system for providing electric motor control to a plurality of motor loads. The system comprises a plurality of motor controllers that are configurable into different arrangements of motor controllers. The system further comprises a central controller that is operable to individually set a phase and/or frequency of respective PWM carrier signals for the motor controllers, wherein the central controller is configured to set the phase and/or frequency of the PWM carrier signals for the motor controllers within a respective arrangement of motor controllers differently depending on the configuration of the motor controllers within the arrangement.

Abstract: An output filter for a power train between a power supply and a motor, the filter comprising a common mode inductor, comprising an inductance for each phase line of the power train, and a resistance for each phase line, connected in parallel with the respective phase line inductance of the common mode inductor.

Abstract: A damper for a power train, comprising a piezoelectric transformer and a load element connected across the output of the piezoelectric transformer.

Abstract: A motor drive system includes an input portion arranged to receive a DC input voltage across first and second conductors. An inverter is connected across the first and second conductors, and is arranged such that, in a normal mode, the inverter receives the DC input voltage and generates an AC drive voltage. A motor is connected to the inverter and is arranged such that, in the normal mode of operation, the motor receives the AC drive voltage. A first normally-open switch is connected along the first conductor between the input portion and the inverter. A damping controller comprising a second normally-closed switch and a damping means is connected in series between the first and second conductors. When the operated in the normal mode, the first switch is closed and the second switch is open. In a damping mode, the first switch is open and the second switch is closed.

Abstract: A motor drive system comprises a power converter arranged to supply an input voltage to a motor connected to the power converter by a cable arrangement. The cable arrangement includes first, second, and third conductors, each of said conductors being electrically coupled at one end to the power converter, and to the motor at the other end. A resistive portion is connected to a respective node of each of said first, second, and third conductors. A capacitive portion is connected to the resistive portion in series. A switching portion is connected in parallel to the capacitive portion and is operable in open and closed states. In the closed state, the capacitive portion is bypassed, providing for dissipation of regenerative energy from the motor. In the open state, the capacitive portion is not bypassed, and acts with the resistive portion to provide RC damper functionality to mitigate transmission line effects from the conductors.

Abstract: A power train is described herein comprising a load, a first power supply for providing power to the load, a DC-link capacitor connected to the load, a main converter configured to convert DC power to AC power for powering the load; and pre-charge circuitry. The pre-charge circuitry comprises pre-charge means configured to, during a first, pre-charge phase, prevent said power from being provided to said load but provide power to said DC-link capacitor to charge said DC-link capacitor, and, further configured to, during a second, post-charge phase, allow said power to be provided from said first power supply to said load. A method for providing power to the load is also described herein.

Abstract: A sensor system for monitoring a motor in an aircraft includes a wireless sensor arranged to measure a parameter of the motor. The wireless sensor is further arranged to transmit the parameter to an external wireless receiver. An energy harvesting unit is provided that a mass-spring unit arranged to be mechanically coupled to the aircraft and is arranged to convert mechanical energy arising from motion of the mass-spring unit to electrical energy, and to supply said electrical energy to the wireless sensor.

Abstract: A system and method for monitoring the health of a Litz wire by representing the wire as a transmission line, terminated at each end, and using time domain reflectometry (TDR) on a pulse induced in the transmission line to monitor the state of the strands of the wire.