Dyson Technology Limited

Dyson Technologies Limited

Stephen Greetham

Andrew Charlton Clothier

Tuncay Celik

Yu Chen

Hanping Dai

Matthew John Childe

Richard Iain Mockridge

David John Hawker

Neil William Phillips

Howard Charles Fulford

Nicholas Dalibor Tuftnell

Mark Henry Haywood

Nigel James Leighton

Maté Horvát

Nicholas Tuftnell

Matthew Childe

Howard Fulford

A drive circuit for a brushless motor is described. The drive circuit includes a converter for connection to a phase winding of the motor, and a controller. The converter includes a plurality of switches and the controller controls the states of the switches to configure the converter in one of a plurality of configurations. In a first configuration, current is permitted to flow through the phase winding in a first direction and in a second opposite direction. In a second configuration, current is permitted to flow through the phase winding in the first direction and is prevented from flowing through the phase winding in the second direction. The controller includes an input for receiving a signal indicative of current in the converter, and the controller configures the converter from the first configuration to the second configuration in response to a characteristic of the current.

Drive circuit for a brushless motor

A gate driver is described for driving switches. The gate driver includes an input for receiving a signal indicative of a polarity of a voltage or current, and outputs for outputting gate signals for driving the switches. In response to a fault condition, the gate driver generates gate signals at the outputs that depend on the polarity of the voltage or current.

Gate driver

A buck-boost converter is described that includes input terminals, output terminals, a first group of devices, a second group of devices, an inductor, a capacitor, and a controller. Each group of devices includes a first switch, a second switch, and a third switch or diode connected in series. Each group of devices further includes a first node located between the first switch and the second switch, and a second node located between the second switch and the third switch or diode. A first of the input terminals is connected to the first node of the first group of devices, and a second of the input terminals is connected to the first node of the second group of devices. The inductor is connected between the second node of the first group of devices and the second node of the second group of devices. The first group of devices, the second group of devices, and the capacitor are connected in parallel across the output terminals, and the controller controls the switches of the first group of devices and the second group of devices.

AC-DC buck-boost converter

A battery system comprising positive and negative charge-discharge terminals, first and second batteries, first and second unidirectional switches, and a bridging switch. The first battery and the first unidirectional switch are connected in series across the charge-discharge terminals such that the first unidirectional switch provides a conductive path from the positive charge-discharge terminal to a positive terminal of the first battery. The second battery and the second unidirectional switch are connected in series across the charge-discharge terminals such that the second unidirectional switch provides a conductive path from the negative terminal of the second battery to the negative charge-discharge terminal. The batteries and the bridging switch are connected in series across the charge-discharge terminals, with the bridging switch being located between the positive terminal of the first battery and the negative terminal of the second battery.

Battery system

A method of controlling a brushless motor that includes sensing a temperature and using the sensed temperature to define a current limit. A lower current limit is then defined for a lower sensed temperature. A winding of the motor is sequentially energized and de-energized, with the winding being de-energized when current in the winding exceeds the defined current limit.

Control of a brushless motor

An AC/AC boost converter comprising input terminals, output terminals, an inductor, a bridge arm comprising a pair of bi-directional switches, a capacitor and a control circuit for controlling the switches. The bridge arm and the capacitor are connected in parallel across the output terminals. The inductor has a first end connected to one of the input terminals and a second end connected to one of an end and a junction of the bridge arm, the junction being located between the two switches. Another of the input terminals is then connected to the other of the end and the junction of the bridge arm. An AC power supply supplies an AC input voltage at the input terminals, and the control circuit controls the switches of the bridge arm such that an AC output voltage is supplied at the output terminals, the AC output voltage being greater than the AC input voltage.

Drive circuit for a brushless motor having an AC/AC boost converter

A stator core that includes a pair of poles separated by an air gap. Each pole includes a first side adjacent the air gap and a second opposite side remote from the air gap. A pole arc is formed in the first side and an arcuate mounting recess is formed in the second side of each pole. Additionally, an electric machine that includes the stator core.

Stator core

An electric machine that includes a permanent-magnet rotor and a stator. The stator includes a plurality of poles, each pole having a leading edge and a trailing edge relative to the direction of rotation of the rotor. The leading edge of each pole is thicker than the trailing edge in a direction normal to the rotational axis of the rotor.

Unidirectional electric machine comprising a permanent magnet rotor and stator

A method of preheating a brushless motor that includes sequentially energizing and de-energizing a phase winding over one or more drive periods. The phase winding is energized in the same direction throughout each drive period so as to lock a rotor of the motor at an aligned position.

Method of preheating a brushless motor

A method of controlling a brushless motor that includes rectifying an alternating voltage to provide a rectified voltage, exciting a winding of the motor with the rectified voltage for a conduction period over each electrical half-cycle of the motor, and updating the conduction period in response to a zero-crossing in the alternating voltage. Additionally, a control system that implements the method, and a motor system that incorporates the control system.

A method of controlling a brushless motor that includes exciting a winding of the motor until current in the winding exceeds a threshold, and then continuing to excite the winding for an overrun period. The length of the overrun period is adjusted in response to a change in one of time, motor speed and excitation voltage. Additionally, a control system that implements the method, and a motor system that incorporates the control system.

A method of controlling a brushless motor that includes rectifying an alternating voltage to provide a rectified voltage having a ripple of at least 50%, exciting a winding of the motor with the rectified voltage, and performing a first process or a second process in response to current in the winding exceeding a threshold that is proportional to the rectified voltage. The first process includes freewheeling the winding, while the second process includes continuing to excite the winding for an overrun period and freewheeling the winding at the end of the overrun period. Additionally, a control system that implements the method, and a motor system that incorporates the control system.

A method of controlling a brushless permanent-magnet motor that includes rectifying an alternating voltage to provide a rectified voltage having a ripple of at least 50%, and exciting a winding of the motor with the rectified voltage. The winding is excited in advance of zero-crossings of back EMF by an advance period and is excited for a conduction period over each electrical half-cycle of the motor. The advance period and/or the conduction period are then adjusted in response to changes in the speed of the motor and/or the RMS value of the alternating voltage so as to maintain constant average power. Additionally, a control system that implements the method, and a motor system that incorporates the control system.

Control of a brushless permanent-magnet motor

A method of controlling a brushless motor that includes rectifying an alternating voltage to provide a rectified voltage, exciting a winding of the motor with the rectified voltage and freewheeling the winding when current in the winding exceeds a threshold. The winding is freewheeled for a freewheel period, which is updated in response to a zero-crossing in the alternating voltage. Additionally, a control system that implements the method, and a motor system that incorporates the control system.

A method of controlling a brushless motor that includes exciting a winding of the motor in advance of predetermined rotor positions by an advance period. The length of the advance period is defined by a waveform that varies periodically with time. Additionally, a control system that implements the method, and a motor system that incorporates the control system.

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Malmesbury, United Kingdom

Stephen Greetham