Abstract: A control system for an electrical motor comprises a rotor, a stator having a plurality of phase windings, and an inverter for applying voltage to the plurality of phase windings by connecting individual phase windings to a first or second voltage level. The control system is configured to measure a first rate of change of current in a first phase winding, of said plurality of phase windings, connected to the first voltage level, to measure a second rate of change of current in a second, different phase winding connected to the first voltage level, and to calculate a difference between the first and second rate of change of current. The control system is further configured to use the calculated difference to obtain data related to a position of the rotor.

Abstract: A coil structure for an electromagnetic device comprising a conductor configured to provide a coil comprising one or more coil turns around a magnetic core to induce a magnetic flux in the magnetic core when in use. The conductor comprises one or more a first parts comprising a plurality of sub-conductors in parallel, and one or more second parts coupled in series with the first part(s), wherein the or each second part comprises a single sub-conductor or a lesser number of sub-conductors in parallel.

Abstract: A supercharger includes a magnetic flux switching motor and a wheel. The motor includes a rotor; a stator stores the rotor therein and includes stator projecting portions projecting inward in a radial direction from an internal circumferential portion toward the rotor; a field source provided in a field slot formed between the stator projecting portions to generate a magnetic field of a constant direction; an armature coil provided in an armature slot; and a controller applying a single-phase current to the armature coil and changing a direction of the applied single-phase current to change a direction of a magnetic field generated from the armature coil and rotate the rotor. The wheel is attached to the rotor, and rotates together with rotation of the rotor to compress the air.

Abstract: There is described a system for measuring an environmental parameter such as temperature experienced by a resistive component such as a thermistor (107) in a galvanically isolated circuit, or for measuring the voltage developed by a component. The system comprises a measurement circuit (1) comprising a voltage pulse generator (114). The measurement circuit is inductively coupled to the galvanically isolated circuit by a flyback transformer (101) such that a stable voltage (V104) across a first capacitor (114) in the measurement circuit after many voltage pulses is proportional to a stable voltage (V106) across a second capacitor (106) connected across the component in the galvanically isolated circuit. The stable voltages across the first and second capacitors are adjustable by adjusting a duty cycle of the voltage pulses.

Abstract: There is described a synchronous reluctance machine having a plurality of poles and comprising a stator with a plurality of spaced slots and a rotor. The rotor has one direct axis and one quadrature axis for each pole and comprises a plurality of flux barriers, each extending to a circumference thereof at least one barrier point. Successive angular separations between barrier points around the circumference of the rotor increase or decrease when moving around half a pole pitch from an initial axis to an adjacent finishing axis, the initial axis being one of a direct axis or a quadrature axis and the finishing axis being the other of a direct axis and a quadrature axis. The increase or decrease in size may be governed by a systematic progressive series.

Abstract: A control system for an electronically commutated motor (401) can rotate smoothly to very low speeds without using a high resolution encoder and can respond to variations in load without excessive speed fluctuations. The control system can be applied to motors operating with low resolution encoders and motors operating with sensorless rotor position feedback. The electronic control system can vary the magnitude and frequency of the stator excitation applied to one or more stator phase windings, the electronic control system comprising a frequency setting section (402) and a magnitude setting section (403) characterized by the fact that the frequency setting section (402) is constrained to operate over a limited range of frequencies, the maximum frequency being a function which is closely related to the frequency associated with rotation of the rotor at the desired speed.

Abstract: Disclosed herein is a design for flux switching machines with one or more armature windings which can deliver controlled torque, in either selected direction on start up, without the use of a mechanical position sensor. Flux switching machines without sensors can operate equally well in either direction. The invention discloses design features for such machines which improves the torque profile of the motor with angle. In three phase machines this delivers higher torque and lower ripple torque. In single phase flux switching machines the invention allows the rotor to be placed in a position where maximum torque can be delivered in either direction by selection of either positive or negative armature current. Rotor slotting is introduced to create a path of low permeability across a rotor tooth with minimal impact on the normal torque producing flux paths. Asymmetry of stator slots is used to further create a stable rotor position when energized by predominantly field means or armature means.

Abstract: There is described a system for measuring an environmental parameter such as temperature experienced by a resistive component such as a thermistor (107) in a galvanically isolated circuit, or for measuring the voltage developed by a component. The system comprises a measurement circuit (1) comprising a voltage pulse generator (114). The measurement circuit is inductively coupled to the galvanically isolated circuit by a flyback transformer (101) such that a stable voltage (V104) across a first capacitor (114) in the measurement circuit after many voltage pulses is proportional to a stable voltage (V106) across a second capacitor (106) connected across the component in the galvanically isolated circuit. The stable voltages across the first and second capacitors are adjustable by adjusting a duty cycle of the voltage pulses.

Abstract: A power supply circuit having at least two conversion stages wherein the first conversion stage includes input terminals for connection to an ac or dc supply, an electronic converter with constant output current characteristics and output terminals for connection to at least one second conversion stages. Each second conversion stage includes input terminals to receive a substantially constant current input from a first conversion stage, current multiplier circuit and output terminals for connection to a load. The electric converter of the first conversion stage is a high frequency resonance converter having a series parallel resonant converter with an inductance connected in series with a capacitor. The output terminals for connection to the second conversion stage are connected across the capacitor and the inductance. Circuits are particularly suitable for lighting applications, for controlling the large number of LEDs in LED display panels or in backlighting for televisions and LCD displays.

Abstract: There is an increasing need for simple and low cost power supplies to control loads such as battery chargers and LEDs. It is the object of this invention to provide an alternative method for the control of current in such loads with very high efficiency and to reduce the variation of load current with supply voltage. This invention is particularly relevant to LED power supplies or battery chargers and provides an electronic power supply for the control of an electrical load connected to an electrical source, the electrical load comprising a main load with at least one LED and an auxiliary load with at least one LED, the electronic power supply comprising a series compensation block connected in series with the main load and the voltage source, the series compensation block providing a voltage in opposition to the voltage source by directly controlling the power delivered to the auxiliary load and indirectly controlling the power converted in the main load.

Abstract: An observer (404), operating during a time when open loop control (402) is being used to drive a synchronous motor (401), the output of the observer (404) being a signal, E_I_angle, related to the angle between a rotational EMF vector and the current excitation vector, the observer (404) determining the angle by an iterative calculation incorporating a summation term, the summation term summing the variation of the quadrature component of a rotational EMF vector relative to an estimated EMF position vector, and using the angle output of the observer to update the estimate of the rotational EMF position vector. In a further aspect of the invention the observer output signal, E_I_angle, can be used to determine the transition to closed loop control (405), when the observer output signal reaches a value indicating conditions close to pull out conditions.

Abstract: An observer (404), operating during a time when open loop control (402) is being used to drive a synchronous motor (401), the output of the observer (404) being a signal, E_I_angle, related to the angle between a rotational EMF vector and the current excitation vector, the observer (404) determining the angle by an iterative calculation incorporating a summation term, the summation term summing the variation of the quadrature component of a rotational EMF vector relative to an estimated EMF position vector, and using the angle output of the observer to update the estimate of the rotational EMF position vector. In a further aspect of the invention the observer output signal, E_I_angle, can be used to determine the transition to closed loop control (405), when the observer output signal reaches a value indicating conditions close to pull out conditions.

Abstract: Disclosed herein is a design for flux switching machines with one or more armature windings which can deliver controlled torque, in either selected direction on start up, without the use of a mechanical position sensor. Flux switching machines without sensors can operate equally well in either direction. The invention discloses design features for such machines which improves the torque profile of the motor with angle. In three phase machines this delivers higher torque and lower ripple torque. In single phase flux switching machines the invention allows the rotor to be placed in a position where maximum torque can be delivered in either direction by selection of either positive or negative armature current. Rotor slotting is introduced to create a path of low permeability across a rotor tooth with minimal impact on the normal torque producing flux paths. Asymmetry of stator slots is used to further create a stable rotor position when energised by predominantly field means or armature means.

Abstract: A control system for an electronically commutated motor (401) can rotate smoothly to very low speeds without using a high resolution encoder and can respond to variations in load without excessive speed fluctuations. The control system can be applied to motors operating with low resolution encoders and motors operating with sensorless rotor position feedback. The electronic control system can vary the magnitude and frequency of the stator excitation applied to one or more stator phase windings, the electronic control system comprising a frequency setting section (402) and a magnitude setting section (403) characterised by the fact that the frequency setting section (402) is constrained to operate over a limited range of frequencies, the maximum frequency being a function which is closely related to the frequency associated with rotation of the rotor at the desired speed.

Abstract: There is an increasing need for simple and low cost power supplies to control loads such as battery chargers and LEDs. It is the object of this invention to provide an alternative method for the control of current in such loads with very high efficiency and to reduce the variation of load current with supply voltage. This invention is particularly relevant to LED power supplies or battery chargers and provides an electronic power supply for the control of an electrical load connected to an electrical source, the electrical load comprising a main load with at least one LED and an auxiliary load with at least one LED, the electronic power supply comprising a series compensation block connected in series with the main load and the voltage source, the series compensation block providing a voltage in opposition to the voltage source by directly controlling the power delivered to the auxiliary load and indirectly controlling the power converted in the main load.

Abstract: An electrical machine for converting electrical energy into mechanical energy and/or mechanical energy into electrical energy, including at least one rotor position sensor device configured to undertake the steps of measuring an electrical signal during a switching cycle in an end region, and comparing the measurement with at least one similar measurement in at least one previous switching cycle to determine if a known rotor position has been reached.

Abstract: A power supply circuit which offers a high efficiency and cost competitive solution to driving one or more low voltage LED strings from a higher voltage ac or dc supply. The power supply provides a dimming capability either by direct variation of the input supply or independently of the input supply by a simple internal controller. Aspects of the invention may be used without current feedback while obtaining acceptable current regulation, even under significant changes in the LED voltage or number of LEDs in a string. The power supply can drive one or more LED strings from a single power supply without the need to individually monitor the current in each string. A very low cost method to drive three colour LEDs and independently vary the current through each colour of LED to create a low cost colour blending power supply is provided.

Abstract: This invention relates to the control of electrical machines and is concerned more particularly, though not exclusively, with the control of flux switching brushless permanent magnet and switched reluctance electrical machines without a mechanical shaft position sensor. Brushless Reluctance and permanent magnet motors can be used in many applications, since they do not require the use of commutators or brushes in supplying electrical power to the rotor of the motor.

Abstract: The present invention relates to control of electrical machines and in particular, though not exclusively, to control of synchronous machines such as hybrid stepping motors, flux switching machines and brushless permanent magnet motors and generators.

Abstract: The present invention relates to control of electrical motors and in particular, to the design and control of reluctance motors capable of micro-stepping position control. According to the invention there is provided a single stack variable reluctance machine with salient stator teeth and salient rotor teeth, the stator further comprising field magnet sections created by either permanent magnets or field windings or a combination of permanent magnets and field windings, and further comprising armature windings connected to form at least two armature phase windings, the armature phase windings connected to a power source or power electronic inverter for the supply of positive and negative current to at least two armature phase windings such that the rotor rotates in small incremental steps in response to small changes in the current in one or more of the phase windings.