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: A power adaptor (20) for a lighting unit (50) having a solid state light source (50a,50b,50c) is disclosed. The power adaptor (20) comprises an input (22) for connection to a mains power supply, a power transfer module (40a,40b,40c,140a) that is coupled to the input (22) and provides an output suitable for driving the solid state light source (50a,50b,50c), and a controller (30) that receives a voltage signal from the input (22) and is able to deliver a control signal to the power transfer module (40a,40b,40c,140a) for reducing the power drawn from the input (22). The power adaptor (20) draws current from the input (22) as a function of the voltage at the input (22) in order that the power adaptor (20) appears as a variable resistor to the mains supply.

Abstract: An electronic resonant circuit of very high efficiency which is suitable for driving loads with a known and controlled current. The resonant circuit has input terminals and output terminals with a first reactance Xs, in series with an input terminal, a second reactance XL, in series with an output terminal, and a reactance Xp, connected such that there is a series connection path between the first input terminal through Xs and Xp to the second input terminal and such that there is also a second series connection path between the first output terminal through XL and Xp to the second output terminal the input terminals being driven from a high frequency inverter, the output terminals being connected to a load, the value of the reactances Xs, XL and Xp being chosen such that at least one frequency, the reactances of Xs, XL and Xp are approximately similar in magnitude.

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: A power adaptor (20) is provided, comprising an input (22) for connection to an AC power supply, and a resonant circuit (34) coupled to the input (22) that provides an output suitable for driving a load (50). The capacitance and inductance of the resonant circuit (34) are selected to provide a pre-determined change in effective voltage, and a corresponding pre-determined change in effective current, between the input (22) and the output (24) of the power adaptor (20).

Abstract: A flux switching electric motor (102) is disclosed. The motor comprises a rotor (104), a stator (106), field windings (124, 126) and armature windings (128, 130). #A microcontroller (134) controls supply of electrical current to the field and armature windings. A rotor position sensor includes a divider for (i) receiving an input signal dependent upon the rate of change of current in at least one field winding, (ii) receiving an input signal dependent upon the voltage across at least one armature winding, current through which causes at least part of the current in the field winding, and (iii) providing the microcontroller (134) with a control signal which is dependent upon the ratio of the input signals received by the divider.

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.

Abstract: This invention relates to the control of electrical machines and is concerned more particularly, though not exclusively, with the control of flux switching electrical machines without a mechanical shaft position sensor.

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: A power adaptor (20) for a lighting unit (50) having a solid state light source (50a,50b,50c) is disclosed. The power adaptor (20) comprises an input (22) for connection to a mains power supply, a power transfer module (40a,40b,40c,140a) that is coupled to the input (22) and provides an output suitable for driving the solid state light source (50a,50b,50c), and a controller (30) that receives a voltage signal from the input (22) and is able to deliver a control signal to the power transfer module (40a,40b,40c,140a) for reducing the power drawn from the input (22). The power adaptor (20) draws current from the input (22) as a function of the voltage at the input (22) in order that the power adaptor (20) appears as a variable resistor to the mains supply.

Abstract: A flux switching electric motor (102) is disclosed. The motor comprises a rotor (104), a stator (106), field windings (124, 126) and armature windings (128, 130). #A microcontroller (134) controls supply of electrical current to the field and armature windings. A rotor position sensor includes a divider for (i) receiving an input signal dependent upon the rate of change of current in at least one field winding, (ii) receiving an input signal dependent upon the voltage across at least one armature winding, current through which causes at least part of the current in the field winding, and (iii) providing the microcontroller (134) with a control signal which is dependent upon the ratio of the input signals received by the divider.

Abstract: An electrical machine having stator (30) and rotor (31) is disclosed. The motor has field windings (F) and armature windings (A) energized by a suitable power electronic controller (401). A controller (400) sends signals to the power electronic controller (401) to control the armature current to control operation of the machine. When the machine is operating as a motor, the armature windings (A) will be supplied with electrical current from the power electronic controller by the application of applied voltage in synchronism with the rotation of the rotor (31). A mutually induced first electrical signal dependent on rotational position of the rotor will be induced within the field windings (F). This will create a superimposed gradient in the field current delivered by the power electronic controller (401).

Abstract: The invention relates to tall oil fatty acid compositions having low sulfur content, as well as methods of using and making the same.

Abstract: An electrical machine having stator (30) and rotor (31) is disclosed. The motor has field windings (F) and armature windings (A) energized by a suitable power electronic controller (401). A controller (400) sends signals to the power electronic controller (401) to control the armature current to control operation of the machine. When the machine is operating as a motor, the armature windings (A) will be supplied with electrical current from the power electronic controller by the application of applied voltage in synchronism with the rotation of the rotor (31). A mutually induced first electrical signal dependent on rotational position of the rotor will be induced within the field windings (F). This will create a superimposed gradient in the field current delivered by the power electronic controller (401).