Abstract: Systems and methods for operating a magnetic resonance imaging (MRI) system are provided. The MRI system includes a magnetics system and a power system configured to provide power to at least some of the magnetics system. The power system includes an energy storage device and a power supply configured to receive mains electricity. The MRI system also includes at least one controller configured to control the MRI system to operate in accordance with a pulse sequence at least in part by generating, by using power supplied by the power supply and supplemental power supplied by the energy storage device, at least one gradient field using at least one gradient coil of the magnetics system.

Abstract: A speed regulating hand brake mechanism and method for speed regulation of the speed regulating hand brake mechanism is disclosed. The mechanism includes: a housing, wherein an installation cavity is defined inside the housing; a speed regulating button is hinged to the side wall of the housing; an installation cavity is internally provided with the driving part hinged to the speed regulating button; the rack is hinged to the driving part and can slide along the inner wall of the installation cavity in a horizontal direction after receiving the pressing force transmitted from the speed regulating button; the encoder is fixed on a first fixing plate in the installation cavity, the rack drives a gear arranged at the top of the encoder to rotate, and changes the code value output by the encoder; the elastic end of the return piece is located inside the speed regulating button.

Abstract: A drive circuit for driving an electro-optical device like an optically switchable glazing, e.g. a glass panel provided with a PDLC or SPD layer, comprises a set of input terminals for receiving an alternating input voltage at a first frequency; a set of output terminals for supplying an alternating output voltage at a second frequency; a control circuit generating a control signal dependent on an input signal, the input signal representing a charge state of the electro-optical device; and a current-direction circuit for controlling a current-flow direction of an electrical current in response to the control signal. The control circuit and the current-direction circuit are thereby configured to control the second frequency such that the electro-optical device is prevented from degradation, while keeping an energy consumption low.

Abstract: A power conversion apparatus includes: a line breaker that is connected in series to a direct-current power supply; a first capacitor that is connected in parallel to the direct-current power supply through the line breaker; a discharge circuit that includes a resistor and a first switching circuit connected in series and is connected in parallel to the first capacitor; a power converter for driving a synchronous machine; a second capacitor that is connected in parallel to a direct-current side of the power converter; a second switching circuit that is connected in series between the first capacitor and the second capacitor; and a control circuit for controlling the discharge circuit. The control circuit controls the discharge circuit on the basis of the voltage of the first capacitor and the voltage of the second capacitor.

Abstract: An embodiment of an electric motor car control system includes a resistor connected parallel to a main motor cut-off switch, or a switch for grounding terminals of the main motor, to discharge electric charges accumulated in stray capacitances of the main motor, whereby the electric motor car control system can prevent electrical shocks due to electric charges accumulated in main motor stray capacitances.

Abstract: A power tool includes a tool housing, an electric motor inside the housing, and a power interface facilitating a connection to a power source. At least four actively-controlled power components are configured as an H-bridge to modulate a supply of power from the power interface to the electric motor. A user-actuated input unit outputs a first signal indicative of a desired power output level to the electric motor and a second signal indicative of a desired direction of current flow to the electric motor. A control unit controls the supply of power to the electric motor using two of said power components with synchronous rectification for pulse-width modulation (PWM) of the supply of power based on the first signal, and to control the direction of current flow to the electric motor using the other two of said power components based on the second signal.

Abstract: A rotation control circuit comprises a motor-driving unit and a rotation-switching unit. The motor-driving unit is coupled to a motor of a fan. The rotation-switching unit is coupled to the motor-driving unit and has at least a charging-discharging circuit for generating a rotation control command, the rotation control command controls the motor to rotate in a forward direction for a time period when the motor starts to operate, and controls the motor to rotate in a backward direction opposite to the forward direction.

Abstract: A clamping circuit is included in a phased motor control circuit, particularly on an electrical connection connected to at least one electrostatic discharge cell and/or the driver control electronics of the phased motor control circuit. The clamping circuit triggers when a voltage that exceeds a clamping turn-on threshold occurs on the electrical connector, sourcing or sinking the discharge current so as to protect the electrostatic discharge cells and/or driver control electronics from destruction by said discharge current.

Abstract: A method for automatically operating a robot, attached to a lawnmower or other unmanned machine, within an enclosed area is disclosed.

Abstract: Disclosed herein is a method for parameter identification in a switched reluctance electric machine comprising: operating the switched reluctance electric machine in response to a desired command; and measuring an actual operating characteristic of the switched reluctance electric machine. The method also includes: modeling the switched reluctance electric machine to formulate an estimated operating characteristic based on the desired command; comparing the actual operating characteristic and the estimated operating characteristic to formulate an error there between; and determining a parameter estimate for the switched reluctance machine based on the error and a previous parameter estimate.

Abstract: A method for sensing motor commutation pulses during motor braking without creating negative voltages, which some junction isolated technologies substantially cannot tolerate. For instance, a commutation pulse sensing circuit containing junction isolated technology may only be able to detect commutation pulses intermittently. An H-bridge motor drive configuration is used to drive and brake a motor. High side clamp diodes are coupled between the motor terminals and a high potential source for high side braking of the motor. As an alternative to high side clamp diodes, any other suitable device may be used, including operating the pair of transistors in the upper portion of the H-bridge in an inverse mode. A commutation pulse sensing circuit is coupled to a terminal of the motor. The use of the high side brake clamp diodes avoids generating negative voltages at the motor terminals.

Abstract: Appliances such as fluorescent lamps and low-voltage DC motors can be operated from household AC without a transformer by employing a current-limiting circuit which is compact, lightweight, reliable, draws less energy, and has fewer power consuming components than do prior devices for driving those applicances. The current-limiting circuit has 4 rectifiers in a bridge circuit and a current-limiting capacitor which should be selected to match the load, a larger capacitor being necessary to supply a larger current. When used to drive a discharge lamp, the current-limiting circuit should also contain an inductive coil in series with the current-limiting capacitor. Otherwise there may be undue flicker. The inductive coil and capacitor together improve the power factor and therefore reduce the current drawn from the line without reducing the lamp output.

Abstract: Four thyristors are interconnected into an AC bridge circuit. With an AC source connected across inputs to the bridge circuit, a DC motor is connected across outputs of the bridge circuit while the thyristors are operated in the phase control mode to control the power supply to the motor from the AC source. In the absence of the AC source the DC motor is serially connected to a battery across the outputs of the bridge circuit with the thyristors operated in the chopping control mode. Also, in the presence of the AC source, a rectifier bridge including thyristors and diodes can be connected across the battery to exclusively charge it from the AC source.