A gate voltage control/gate resistance changing circuit (21) is accommodated in the same package (P1) as a switching element (11), and outputs a driving signal to the switching element (11) to control turning on and off of the switching element (11). When an external signal is input from outside of the package (P1) to a terminal (3c) of the package (P1), a changing unit (221) accommodated in the package (P1) changes the switching speed of the switching element (11) based on the signal.

There is provided a motor control device which enables torque ripple suppressing control high in followability by executing direct voltage control. A motor control device includes a voltage command calculation unit 15 which calculates a d-axis voltage command value V.sub.d.sup.ref and a q-axis voltage command value V.sub.q.sup.ref from a d-axis current command value i.sub.d* and a q-axis current command value i.sub.q* of a motor 6, a feed forward command value calculation unit 23 which calculates a qi-axis voltage feed forward command value V.sup.qff* for generating a q-axis current ripple on the basis of spatial harmonic parameters and the frequency characteristics of a motor winding, and a subtraction unit 10 which subtracts the q-axis voltage feed forward command value V.sub.qff* calculated by the feed forward command value calculation unit 23 from the q-axis voltage command value V.sub.q.sup.ref calculated by the voltage command calculation unit 15.

A method and apparatus are provided for controlling a sensorless multi-phase permanent magnet (PM) motor by sensing induced motor terminal voltages from the PM motor while the rotor is spinning, generating an input voltage vector signal from the plurality of induced motor terminal voltages, projecting the input voltage vector signal to a transformed voltage vector signal which does not include DC-offset components by using a Clarke transformation without a zero component that is applied to the input voltage vector signal, and estimating an initial rotor position of the rotor from the transformed voltage vector signal, wherein said sensing, projecting, and estimating are performed while a power converter for the sensorless multi-phase PM motor is disabled.

The present disclosure provides a motor driving circuit of capable of stopping operation within a short period of time. A bridge circuit of the present disclosure is connected to a fan motor. In response to a stop instruction, a control logic circuit fixes an upper arm of a source phase in which a current flows out to be off in the bridge circuit, and maintains statuses of other upper arms and lower arms. The control logic circuit then fixes the upper arms and the lower arms of all phases of the bridge circuit to be off.

A power management system comprises an AC-power-source controller configured to control power supply between the AC power source and a common DC bus, the AC-power-source controller further configured to limit AC power supplied from the AC power source to the common DC bus to a first AC-power-source power limit; a power inverter configured to invert the DC power on the common DC bus into AC output power for driving the electric motor; a DC power source configured to supply DC power to the common DC bus; and a DC-power-source controller configured to control power supply between the DC power source and the common DC bus, the DC-power-source controller further configured to start supplying DC power from the DC power source to the common DC bus in response to a detection of a voltage drop on the common DC bus from a AC-power-source reference voltage to a DC-power-source reference voltage.

A power tool with a direct current, DC, power source comprising a controller for controlling a driver circuit driving a brushless motor in a power tool, the driver circuit being coupled to a direct current, DC, power source and including a first switching element pair coupled to a first phase winding of the brushless motor and a second switching element pair coupled to a second phase winding of the brushless motor; and the controller being arranged to alternately switch a first switching element of the first switching element pair and a second switching element of the second switching element pair, wherein the first switching element and the second switching elements are coupled to a respective terminal of the DC power source. A power tool comprising such a controller, and a method of controlling a driver circuit driving a brushless motor in a power tool.

An electronic data processor comprises a data storage device in communication with the electronic data processor. A control module stored in the data storage device, the control module comprising software instructions for execution by the electronic data processor to change dynamically the fundamental switching frequency of the control signals to reduce electromagnetic noise within a target frequency band if the fundamental switching frequency is equal to or greater than a threshold fundamental switching frequency.

This power conversion device includes: a current detection unit for detecting current flowing through a rotary electric machine; a switching pattern determination unit for determining a switching pattern on the basis of the detected current, a current prediction value, a current command value, and a current harmonic command value; and a power conversion unit for outputting AC power to the rotary electric machine in accordance with the switching pattern, wherein the switching pattern determination unit determines the switching pattern so that the current value follows the current command value and the current harmonic becomes equal to or smaller than a limit value.

The present invention relates to a system and method for operational acoustic optimization of a variable speed compressor (2) comprising a synchronous motor (6), a frequency inverter (3) and a control block (5), such optimization being carried out by modifying the switching frequency of the supply signal (9) of the motor (6) contained in the compressor (2), via a control block (5), only during the aligmnent phase of the motor (6), thus, not impairing the performance of the compressor (2), the thermal management of the inverter (3) and the acoustic performance of the system.

Ina power conversion system having a fixed pulse pattern modulation unit 2 that is configured to refer to tables storing therein pulse patterns that determine respective command voltage levels corresponding to phase information for each modulation ratio and to generate a gate signal g on the basis of a command modulation ratio d and a control phase θ and driving a power converter 3 on the basis of the gate signal g, the fixed pulse pattern modulation unit 2 is further configured to, when performing a pulse pattern transition, search for a proper post-transition table reference position and make a command voltage level follow a command voltage level of a post-transition pulse pattern. With this, the power conversion system that can perform the pulse pattern transition without current impulse and that can also be applied to a multi-level power converter having four levels or more can be provided.