Abstract: A variable speed switch includes a switch main body portion which is accommodated in a housing of an electric power tool and mounted to the housing so as to be capable of relative movement, and a load sensor which is provided in the switch main body portion and capable of outputting an electric signal in proportion to the amount of distortion caused by a pressing force. The switch operating portion is mounted on the surface of the housing so as to be capable of relative displacement with respect to the housing and transmits a pressing force applied to the switch operating portion to the load sensor, with the maximum displacement amount of the switch operating portion being set to equal to or less than 5 mm.

Abstract: The brushless motor driver includes a sample and hold circuit which samples and holds a first value of the first comparison signal in a first case in which a current is forced to flow from a first phase coil of the three-phase brushless motor to a second phase coil and no current is forced to flow to a third phase coil in a first period having a preset setting time and a second value of the first comparison signal in a second case in which a current is forced to flow from the second phase coil to the first phase coil and no current is forced to flow to the third phase coil in a second period having the preset setting time subsequent to the first period. The brushless motor driver includes an addition circuit which adds up the first value and the second value sampled and held by the sample and hold circuit and outputs an addition signal depending upon a result of the addition.

Abstract: A motor control device includes an inverter circuit including a plurality of switching elements connected into a three-phase bridge configuration and converting a direct current into a three-phase alternate current, a current detecting element connected to a direct current side of the inverter circuit, thereby generating a signal corresponding to a current value, a PWM signal generating unit which determines a rotor position based on phase currents of the motor and generates a three-phase PWM signal pattern so that the signal pattern follows the rotor position, and a current detecting unit detecting phase currents based on the signal generated by the current detecting element and the PWM signal pattern. The PWM signal generating unit generates the three-phase PWM signal pattern so that the current detecting unit is capable of detecting two phase currents in synchronization with advent of two fixed time-points within a carrier period of the PWM signal respectively.

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 electric motor and a control unit are juxtaposed in a speed reduction gear box. A terminal block is provided at an outer circumference of a flange proximate to a control unit of the electric motor. Terminal block surfaces of the terminal block are provided so that a plane direction faces a direction vertical to a shaft line of the electric motor. A motor side connecting terminal is held on the terminal block surface. The unit side connecting terminals provided at a position proximate to the electric motor of the control unit are arranged so as to overlap with the motor side connecting terminal on the terminal block surface to couple by a coupling portion (fixing screw).

Abstract: A variable speed switch includes a switch main body portion which is accommodated in a housing of an electric power tool and mounted to the housing so as to be capable of relative movement, and a load sensor which is provided in the switch main body portion and capable of outputting an electric signal in proportion to the amount of distortion caused by a pressing force. The switch operating portion is mounted on the surface of the housing so as to be capable of relative displacement with respect to the housing and transmits a pressing force applied to the switch operating portion to the load sensor, with the maximum displacement amount of the switch operating portion being set to equal to or less than 5 mm.

Abstract: A circuit switching element is provided that switches a step-up/step-down bidirectional chopper circuit, arranged between a DC bus and a power storage element, to a first chopper circuit or to a second chopper circuit, whose step-up and step-down characteristics are in a complementary relation. The first and second chopper circuits are used together at a time of charge and discharge. Accordingly, an AC motor drive device having mounted therein a power storage system is obtained, in which the power storage system can perform charge and discharge to and from the power storage element, regardless of a bus voltage and can increase energy use efficiency.

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 method of controlling a motor is provided. The method may determine a speed of the motor, and engage a soft chopping routine on a first switch and a second switch of each phase if the motor speed is relatively low. The first switch may be driven by a first pulse width modulated PWM signal and the second switch being driven by a second PWM signal. The first and second PWM signals may be alternatingly configured such that at least one of the first switch and the second switch is closed at any point during the distributed soft chopping routine and both the first switch and the second switch are never simultaneously open.

Abstract: An electronically commutated motor (ECM) includes windings, a power switch, an infrared transceiver and an electromagnetic shield. The power switch is configured to provide pulse width modulated (PWM) power signals to the windings and to generate a substantial level of electromagnetic noises at PWM frequencies during its switching operation. The infrared transceiver is configured to communicate with an external device using infrared signals and convert electrical signals from and to infrared signals that carry data. The electromagnetic shield is configured to substantially shield the infrared transceiver from the electromagnetic noises of PWM frequencies from the power switch.

Abstract: According to an embodiment, a lead angle control circuit is configured to control a lead angle of a motor drive signal driving a motor. The lead angle control circuit includes a control signal generating section, an upper limit voltage limit section and a lead angle data generating section. The lead angle data generating section is configured to generate a relationship line between lead angle data representing the lead angle and a lead angle control signal, and configured to generate the lead angle data based on the relationship line and the lead angle control signal. The relationship line reaches an upper limit point from a lower limit point through a changing point. In the changing point, the lead angle control signal is a changing point voltage, and the lead angle data represents the lead angle corresponding to a lead angle setting voltage.

Abstract: A control device configured with an external input estimator that reduces a vibration component of a rotational speed of the power transfer system at a rotational speed of the rotary electric machine and estimates transfer system input torque on the basis of the rotational speed of the rotary electric machine, and that estimates external input torque by subtracting at least output torque of the rotary electric machine from the transfer system input torque. A low-vibration speed calculator calculates a low-vibration rotational speed on the basis of the external input torque and vehicle required torque. A rotational speed controller calculates feedback command torque that matches the rotational speed of the rotary electric machine with the low-vibration rotational speed. A torque command value calculator calculates an output torque command value on the basis of the vehicle required torque and the feedback command torque.

Abstract: In a converter of a motor drive control device, one of a first switching element and a second switching element is selected in accordance with a current command value of a current flowing through a reactor. The converter is then controlled so that a drive command for the selected switching element is generated. In this way, the efficiency of the converter is improved while a voltage step-up or step-down operation is performed by the converter.

Abstract: Embodiments of the present invention relate to methods, systems, a machine-readable medium operable in a controller, and apparatus for controlling a multi-phase inverter that drives a multi-phase electric machine. When a sensor fault is detected, a phase current angle is computed based on the feedback stator currents, and used to estimate an angular velocity and an angular position of a rotor of the multi-phase electric machine. When the estimated angular velocity of the multi-phase electric machine is less than a transition angular velocity threshold, an open-circuit response can be applied at the multi-phase inverter by controlling all switches in the multi-phase inverter drive to be open. By contrast, when the estimated angular velocity is greater than the transition angular velocity threshold, a short-circuit response can be applied at the multi-phase inverter by controlling selected switches in the multi-phase inverter drive to connect all phases of the multi-phase inverter to a single bus (e.g.

Abstract: An energy converter includes a magnetism generation mechanism unit that generates a magnetic field when connected to an AC electrical power source, and a rotating mechanism unit having a single turn coil array member in which a plurality of single turn coils is disposed at a predetermined interval and a soft magnetic metal plate disposed on a side of the single turn coil array member opposite to the magnetism generation mechanism unit. The rotating mechanism unit is structured such that the single turn coil array member faces the magnetism generation mechanism unit across a predetermined magnetic gap and rotary driven by the magnetic field. Here, a drive signal period of the electrical power source is a period that maximizes an eddy current generated in the soft magnetic metal plate.

Abstract: A method and apparatus to drive a load using a pulse-width modulated (PWM) signal and spread a spectrum of the PWM signal across a plurality of frequencies while maintaining a constant duty cycle for the load.

Abstract: An alternating current chopper circuit with low noise is disclosed. The circuit includes a switching circuit, a first freewheel circuit, and a second freewheel circuit. The switching circuit has a control switching unit, which turns on and or off accordingly to a control signal. The first freewheel circuit and the second freewheel circuit are for providing a current-conducting path to the motor, when the control switching unit is turned off.

Abstract: A steering control apparatus includes a direct current power source, a three-phase alternating current motor, and a motor driving circuit. An emergency switching element is provided on at least two phases of a three-phase power supply line connected to the three-phase alternating current motor within the motor driving circuit, and the emergency switching element is turned off when an abnormality occurs such that the motor driving circuit is disconnected from the three-phase alternating current motor. The emergency switching element is a MOSFET, and the MOSFETs are provided in pairs in each of the two phases of the three-phase power supply line. Further, parasitic diodes of the pairs of MOSFETs are disposed in opposite orientations to each other.

Abstract: Disclosed is a method for suppressing a speed ripple occurring during an operation of an AC motor by using a torque compensator based on an activation function. The method includes the steps of calculating a speed error ?err based on a reference speed ?ref and an actual speed ?act; calculating a controller output Trm by using the speed error ?err as an input of a PI control and an operation of a compensated torque Tcom; and determining a torque variation based on the controller output Trm and a reference torque Tref and operating the torque variation in relation to an anti-windup gain Ka to use torque variation as an input of an integral (I) control. The method suppresses the speed ripple by compensating for the torque ripple through a controller which calculates the compensated torque by taking the signs of the speed error and the differential speed error into consideration.

Abstract: A stepper motor driver system includes: a digital signal controller configured to digitally synthesize synthesized analog voltage signals that will induce a desired velocity of a stepper motor when applied to a pair of stepper motor windings; and voltage amplifiers, communicatively coupled to the digital signal controller, configured to amplify the synthesized analog voltage signals to produce amplified analog voltage signals and to output the amplified analog voltage signals; where the digital signal controller is configured to synthesize the analog voltage signals by affecting at least one of a phase or an amplitude of each of the analog voltage signals as a function of the desired velocity of the stepper motor.