Abstract: Systems and methods are disclosed for improving common mode transient immunity in silicon digital isolators using capacitive barrier for galvanic isolation. The systems include transmitters and receivers that include differential amplifiers. The differential amplifier may include a first transistor electrically coupled between a first input of the transmitter and a first output of the transmitter, a second transistor electrically coupled between a second input of the transmitter and a second output of the transmitter, a first passive load electrically coupled between the first output of the transmitter and a source rail, and a second passive load electrically coupled between the second output of the transmitter and the source rail, wherein the first and second passive loads have the same impedance; and a bias voltage source configured to bias a gate of the first transistor and a gate of the second transistor.

Abstract: A transient voltage surge protection circuit includes a discharge transistor having a drain coupled to a first point of a voltage input bus, and a source coupled to ground; an RC string having a first capacitor and a first resistor coupled in series; a first charge transistor having a drain coupled to the drain of the discharge transistor, a source coupled to the gate of the discharge transistor, and a gate coupled to a mid-point between the first capacitor and the first resistor; a second charge transistor having a drain coupled to the drain of the discharge transistor and a gate coupled to the gate of the first charge transistor; a Zener diode string coupled to a second point of the voltage input bus and coupled to a third and fourth resistors in series. A midpoint between the third and fourth resistors is coupled to the second resistor.

Abstract: A method of adjusting motor control voltages for a permanent magnet rotor motor comprising three phase coils, each phase coil having two free ends, the three phase coils being without a common node. The method comprises driving the motor by applying motor control voltages in turn to respective pairs of the three phase coils with a remaining one of the three phase coils not being driven. Then, determining for each of the pairs of the three phase coils respective values of a motor operating parameter. The values of the motor operating parameter are compared and, based on said comparison, three-phase stationary reference frame motor control voltages va, vb, vc generated for driving the coils in a field-oriented control (FOC) mode of operation are adjusted to provide adjusted three-phase stationary reference frame motor control voltages v?a, v?b, v?c for driving the coils in the FOC mode of operation.

Abstract: An energy-conserving fluid pump is an apparatus used to transport low viscosity fluids like water and fuel without experiencing cavitation, recirculation, nor motor locking while also conserving energy. The apparatus includes a fluid diffuser, a fluid densifier, a convergent housing, and a strut assembly. The fluid diffuser improves the efficiency of the apparatus by expanding the fluid inflow and maintaining a fluid pressure buildup. The fluid densifier shears the incoming fluid flow from the fluid diffuser and increases the fluid outflow pressure. The convergent housing encloses the fluid diffuser and the fluid densifier while facilitating the outflow of the pressurized fluid without the loss of fluid pressure nor cavitation. In addition, the convergent housing facilitates the transfer of torque to the fluid diffuser for the operation of the apparatus. The strut assembly keeps the fluid densifier stationary while enabling the rotation of the convergent housing and/or the fluid diffuser.

Abstract: The present invention relates to a modular reflux sampler, including a condenser container and a vortex tube. The condenser container is enclosed outside a gas pipeline to be cooled; the vortex tube has a cold air nozzle; the cold air nozzle extends into the condenser container to inject cold air in order to cool the gas pipeline; the vortex tube is connected with a compressed air duct to input compressed air as a cold air raw material; wherein the compressed air duct has a section to pass through the condenser container; and the vortex tube cools the compressed air duct while cooling the gas pipeline, so that the temperature of the compressed air flowing into the vortex tube is reduced, the temperature of the cold air ejected by the cold air nozzle is reduced, the cold air with a lower temperature is input to the condenser container to repeat cooling operation, and a better cooling effect is achieved.

Abstract: A removeable off-ice training blade for use in a convertible ice skate on a non-ice training surface. The blade has an upper retention surface shaped to engage the interior of a blade-holding groove and retention mechanism of the skate and has a lower tread to engage the non-ice training surface. Two side surfaces extend substantially perpendicularly from the lower tread to meet the upper retention surface. The tread surface comprises reflective non-cutting axial edges, to negate any destruction of the non-ice training surface during use of the blade. Certain embodiments of the training blade will include a tread surface that is wider than the upper retention surface, achieved with multiple lower profiles and cross-sections of the blade. Insofar as the training blade will not permit on-ice skating use, it can be removed from the skate for replacement with an ice blade having cutting edges. A skate incorporating the blade, and a related exercise method, are also disclosed.

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 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: One aspect disclosed features an apparatus comprising: an input buffer configured to receive an input voltage pulse as an input, and to output, responsive to a leading edge of the input voltage pulse, a logic high voltage pulse at a first output of the input buffer and a logic low voltage pulse at a second output of the input buffer; an array of L active pull-up devices electrically coupled between a positive supply rail and an output node, each active pull-up device driven by the logic high voltage pulse as modulated by a corresponding bit of a series of N first L-bit binary words; and an array of L active pull-down devices electrically coupled between a negative supply rail and the output node, each active pull-down device driven by the logic low voltage pulse as modulated by a corresponding bit of a series of M second L-bit binary words.

Abstract: Described is a method of aligning a rotor of a polyphase synchronous motor having a permanent magnet rotor to a predetermined, selected, or specified rotor angle. The method comprises sensing or measuring the stator winding voltages/currents during synchronous operation of the motor. Based on the sensed or measured stator winding voltages/currents, a synchronously rotating reference frame vector voltage (Vq) in the q-axis is determined as a product of stator winding resistance (Rs) and stator winding current (iq) in the q-axis. Corresponding polyphase drive voltages for the synchronous motor for the predetermined, selected, or specified rotor angle (?) are determined from the synchronously rotating reference frame vector voltage (Vq). The polyphase drive voltages are applied to align the rotor on stopping at said predetermined, selected, or specified rotor angle (?). The polyphase drive voltages are applied by suitable PWM drive 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: 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 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 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: A system for managing power on distributed devices may include a first device having a master logic and a second device having a slave logic. The master logic may enable the first device to communicate with multiple devices having the slave logic on one or more channels. The slave logic may enable the second device having the slave logic to communicate with the first device and to communicate with a third device having the slave logic. The slave logic may enable the multiple devices having the slave logic to manage operations of the distributed devices.