Abstract: A toothbrush comprising a drive mechanism and electronic circuitry configured to drive the drive mechanism to execute toothbrushing motions is disclosed. The electronic circuitry comprises a drive circuitry and a controller which is configured to form a drive signal to operate the drive circuitry to generate drive current. The drive signal comprises a plurality of signal packets, wherein a signal packet has a signal packet duration and comprises a train of switching signals. The switching signals are configured to repeatedly switch on and switch off drive current supply to the drive mechanism at a switching frequency fs. The signal packet duration is configured to define a rhythm of toothbrushing motions.

Abstract: Described is a method of determining a speed of a synchronous motor having a rotor and a stator having windings. The method comprises sensing currents in the windings of the stator while the rotor is rotating and transforming the currents into a two-dimensional (2D) coordinate system using an alpha-beta (?-?) transformation, wherein the alpha-beta (?-?) transformation is a Clarke transformation, the 2D coordinate system having an ?-axis and a ?-axis. The method includes determining a rotor angle ? from an arc tangent (A tan) of a ratio of a current i? in the ?-axis to a current i? in the ?-axis and determining a speed of the motor from the rotor angle ?.

Abstract: A method of switching from a closed-loop start-up method to a closed-loop synchronous operation motor control algorithm for a synchronous motor having a permanent magnet rotor and stator windings. The method comprises initiating the closed-loop start-up method by energizing the stator windings to drive the permanent magnet rotor using motor control signals based on a detected, estimated, or randomly selected initial standstill angle of the permanent magnet rotor.

Abstract: A multi-phase permanent magnet rotor motor comprises a plurality of phase coil windings with each phase coil winding having two free ends and the plurality of phase coil windings being without a common node. A controller is provided comprising a plurality of full-bridge inverters. Each full-bridge inverter has two output ends electrically connected to the two free ends of a corresponding phase coil winding. The controller is configured to operate the plurality of full-bridge inverters to output pulse modulated control signals to their respective phase coil windings. The outputted pulse modulated control signals can comprise a combination of sine wave signals and full-bridge space vector modulation signals.

Abstract: Described is a method of determining an initial rotor position on start-up of a synchronous motor. The method comprises applying at each of a plurality of pre-set motor angles a pair of voltage vector pulses, the pair of voltage vector pulses comprising a first and second pulses, each having the same amplitude but opposite polarities, the second pulse being applied immediately or near immediately after the first pulse. The method includes determining the stator current responses to said pairs of applied voltage vector pulses at said plurality of pre-set motor angles. Then, the initial rotor position can be determined from either of a stator angle corresponding to a pair of vector voltage pulses resulting in (a) a largest sum of stator currents or (b) where the sum of stator currents changes from a negative to a positive motor angle.

Abstract: Described is a method of determining an initial speed of a synchronous motor having a permanent magnet rotor. The method comprises controlling said motor to cause the rotor to rotate or observing that the rotor is rotating. The method includes sensing stator winding currents and transforming the sensed stator winding currents into a two-dimensional (2D) coordinate system using an alpha-beta (?-?) transformation. The rotor angle ? is determined from an arc tangent (Atan) of the ratio of the current in the ?-axis to the current in the ?-axis. The initial motor speed ? is determined from the determined rotor angle ?.

Abstract: A closed-loop method of starting a permanent magnet synchronous motor comprises driving the rotor by energizing stator windings using motor control signals based on an initial standstill rotor angle. Periodically estimating values of rotor flux linkage magnitude and/or angle based on back-electromotive force (emf) induced in the stator windings by the rotating rotor. The estimated values of rotor flux linkage magnitude are used to estimate respective new rotor angles which are used to generate updated motor control signals to drive the rotor. Control of the motor is switched-over to a closed-loop synchronous operation motor control algorithm in response to any one or any combination of the following conditions: at a predetermined period of time from initiation of the closed-loop start-up method; or upon determination that the rotor has reached a minimum operating speed; or upon determination that the estimated value of rotor flux linkage magnitude reaches or exceeds a threshold value.

Abstract: A multi-phase permanent magnet rotor motor comprises a plurality of phase coil windings with each phase coil winding having two free ends and the plurality of phase coil windings being without a common node. A controller is provided comprising a plurality of full-bridge inverters. Each full-bridge inverter has two output ends electrically connected to the two free ends of a corresponding phase coil winding. The controller is configured to operate the plurality of full-bridge inverters to output pulse modulated control signals to their respective phase coil windings. The outputted pulse modulated control signals can comprise a combination of sine wave signals and full-bridge space vector modulation signals.

Abstract: Described is a method of controlling operation of a synchronous motor. The method comprises, during constant power/speed motor operation, determining a value of a stator voltage (vs2) for an orthogonal rotating reference frame of the motor. Comparing the value of the determined stator voltage (vs2) to a threshold voltage (vs_max12), said threshold voltage (vs_max12) having a value between that of a maximum stator voltage (vs_max02) for a basic speed mode of operation of the motor and that of a maximum stator voltage (vs_max22) of the motor closed loop controller. If the determined value of the stator voltage (vs2) is greater than or equal to the value of the threshold voltage (vs_max12), then controlling operation of the motor in a flux weakening mode of operation until a value of a current component (id??id) in a d-axis reaches a maximum negative value (?idmax), or until the value of the stator voltage (vs2) is less than the value of the threshold voltage (vs_max12).

Abstract: Described is a method of controlling operation of a synchronous motor. The method comprises, during constant power/speed motor operation, determining a value of a stator voltage (vs2) for an orthogonal rotating reference frame of the motor. Comparing the value of the determined stator voltage (vs2) to a threshold voltage (vs2_max1), said threshold voltage (vs2_max1) having a value between that of a maximum stator voltage (vs2_max0) for a basic speed mode of operation of the motor and that of a maximum stator voltage (vs2_max2) of the motor closed loop controller. If the determined value of the stator voltage (vs2) is greater than or equal to the value of the threshold voltage (vs2_max1), then controlling operation of the motor in a flux weakening mode of operation until a value of a current component (id??id) in a d-axis reaches a maximum negative value (?idmax), or until the value of the stator voltage (vs2) is less than the value of the threshold voltage (vs2_max1).

Abstract: A multi-phase permanent magnet rotor motor comprises a plurality of phase coil windings with each phase coil winding having two free ends and the plurality of phase coil windings being without a common node. A controller is provided comprising a plurality of full-bridge inverters. Each full-bridge inverter has two output ends electrically connected to the two free ends of a corresponding phase coil winding. The controller is configured to operate the plurality of full-bridge inverters to output pulse modulated control signals to their respective phase coil windings. The outputted pulse modulated control signals can comprise a combination of sine wave signals and full-bridge space vector modulation signals.

Abstract: Described is a method of determining an initial speed of a synchronous motor having a permanent magnet rotor. The method comprises controlling said motor to cause the rotor to rotate or observing that the rotor is rotating. The method includes sensing stator winding currents and transforming the sensed stator winding currents into a two-dimensional (2D) coordinate system using an alpha-beta (?-?) transformation. The rotor angle ? is determined from an arc tangent (Atan) of the ratio of the current in the ?-axis to the current in the ?-axis. The initial motor speed ? is determined from the determined rotor angle ?.

Abstract: Described is a method of determining an initial rotor position on start-up of a synchronous motor. The method comprises applying at each of a plurality of pre-set motor angles a pair of voltage vector pulses, the pair of voltage vector pulses comprising a first and second pulses, each having the same amplitude but opposite polarities, the second pulse being applied immediately or near immediately after the first pulse. The method includes determining the stator current responses to said pairs of applied voltage vector pulses at said plurality of pre-set motor angles. Then, the initial rotor position can be determined from either of a stator angle corresponding to a pair of vector voltage pulses resulting in (a) a largest sum of stator currents or (b) where the sum of stator currents changes from a negative to a positive motor angle.

Abstract: A closed-loop method of starting a permanent magnet synchronous motor comprises driving the rotor by energizing stator windings using motor control signals based on an initial standstill rotor angle. Periodically estimating values of rotor flux linkage magnitude and/or angle based on back-electromotive force (emf) induced in the stator windings by the rotating rotor. The estimated values of rotor flux linkage magnitude are used to estimate respective new rotor angles which are used to generate updated motor control signals to drive the rotor. Control of the motor is switched-over to a closed-loop synchronous operation motor control algorithm in response to any one or any combination of the following conditions: at a predetermined period of time from initiation of the closed-loop start-up method; or upon determination that the rotor has reached a minimum operating speed; or upon determination that the estimated value of rotor flux linkage magnitude reaches or exceeds a threshold value.

Abstract: Described is a method of controlling operation of a synchronous motor. The method comprises, during constant power/speed motor operation, determining a value of a stator voltage (vs2) for an orthogonal rotating reference frame of the motor. Comparing the value of the determined stator voltage (vs2) to a threshold voltage (vs2_max 1), said threshold voltage (vs2_max 1) having a value between that of a maximum stator voltage (vs2_max 0) for a basic speed mode of operation of the motor and that of a maximum stator voltage (vs2_max 2) of the motor closed loop controller. If the determined value of the stator voltage (vs2) is greater than or equal to the value of the threshold voltage (vs2_max 1), then controlling operation of the motor in a flux weakening mode of operation until a value of a current component (id??id) in a d-axis reaches a maximum negative value (?id max), or until the value of the stator voltage (vs2) is less than the value of the threshold voltage (vs2_max 1).

Abstract: A toothbrush comprising a drive mechanism and electronic circuitry configured to drive the drive mechanism to execute toothbrushing motions is disclosed. The electronic circuitry comprises a drive circuitry and a controller which is configured to form a drive signal to operate the drive circuitry to generate drive current. The drive signal comprises a plurality of signal packets, wherein a signal packet has a signal packet duration and comprises a train of switching signals. The switching signals are configured to repeatedly switch on and switch off drive current supply to the drive mechanism at a switching frequency fs. The signal packet duration is configured to define a rhythm of toothbrushing motions.

Abstract: An electronic device including a multi-chip die and a substrate member, said multi-chip die includes a plurality of integrated circuit chips which are integrally formed on the multi-chip die as a unitary member, each the integrated chip includes a plurality of electrodes for making external electrical contacts, the substrate member includes a circuit of a pre-determined pattern and a plurality of electric contacts disposed for making corresponding electrical connections with the electrodes of the integrated chips of the multi-chip die, the plurality of integrated circuit chips of the multi-chip die being connected as a unitary member to the substrate member.

Abstract: An electronic device including a multi-chip die and a substrate member, said multi-chip die includes a plurality of integrated circuit chips which are integrally formed on the multi-chip die as a unitary member, each the integrated chip includes a plurality of electrodes for making external electrical contacts, the substrate member includes a circuit of a pre-determined pattern and a plurality of electric contacts disposed for making corresponding electrical connections with the electrodes of the integrated chips of the multi-chip die, the plurality of integrated circuit chips of the multi-chip die being connected as a unitary member to the substrate member.

Abstract: An electronic device including a multi-chip die and a substrate member, said multi-chip die includes a plurality of integrated circuit chips which are integrally formed on the multi-chip die as a unitary member, each the integrated chip includes a plurality of electrodes for making external electrical contacts, the substrate member includes a circuit of a pre-determined pattern and a plurality of electric contacts disposed for making corresponding electrical connections with the electrodes of the integrated chips of the multi-chip die, the plurality of integrated circuit chips of the multi-chip die being connected as a unitary member to the substrate member.