A method for estimating parameters of a direct current machine by Laplace transform performed by a computer system. The method includes establishing a transient model of the DC machine and a transfer function based on the transient mode; transforming the transfer function from the time domain to the frequency domain by the Laplace transform to obtain each of an armature current and a rotational speed of the DC machine as a function of frequency; expressing the armature current and the rotational speed as polynomial fractions by polynomial regression, and comparing the functions of the frequency and the polynomial fractions to output values of the armature resistance, the armature inductance, the back electromotive force constant, the moment of inertia and the friction coefficient. As such, the accuracy and operational efficiency in estimating the parameters of the DC machine can be improved.

A method for estimating parameters of a direct current machine by Laplace transform performed by a computer system. The method includes establishing a transient model of the DC machine and a transfer function based on the transient mode; transforming the transfer function from the time domain to the frequency domain by the Laplace transform to obtain each of an armature current and a rotational speed of the DC machine as a function of frequency; expressing the armature current and the rotational speed as polynomial fractions by polynomial regression, and comparing the functions of the frequency and the polynomial fractions to output values of the armature resistance, the armature inductance, the back electromotive force constant, the moment of inertia and the friction coefficient. As such, the accuracy and operational efficiency in estimating the parameters of the DC machine can be improved.

A motor drive system includes: a flywheel; a servomotor for buffer which includes a plurality of independent windings and allows the flywheel to rotate; a plurality of inverters for buffer respectively connected to the windings; a plurality of converters respectively connected to the DC links; inverters for drive which perform power conversion between a DC power in the DC links and an AC power which is a drive power or a regenerative power of the servomotor for drive; and a motor control unit for buffer configured to control driving of the servomotor for buffer by controlling power conversion of the respective inverters for buffer respectively connected to the windings.

A motor drive system includes: a flywheel; a servomotor for buffer which includes a plurality of independent windings and allows the flywheel to rotate; a plurality of inverters for buffer respectively connected to the windings; a plurality of converters respectively connected to the DC links; inverters for drive which perform power conversion between a DC power in the DC links and an AC power which is a drive power or a regenerative power of the servomotor for drive; and a motor control unit for buffer configured to control driving of the servomotor for buffer by controlling power conversion of the respective inverters for buffer respectively connected to the windings.

A power supply device for an internal combustion engine, using a generator driven by an internal combustion engine as a power source and supplying power to a first load that needs to be constantly driven to cause the internal combustion engine to operate and a second load that is permitted not to drive during startup of the engine, wherein a first generation coil for driving the first load and a second generation coil for driving the second load are provided to be magnetically-coupled tightly in the generator, and voltage supplied to a load is boosted to a higher voltage value than conventionally achieved by performing chopper control of an energizing current of the first generation coil and an energizing current of the second generation coil while preventing energization from the second generation coil to a load.

A motor drive apparatus includes a converter configured to convert AC power inputted by an AC power supply to DC power and to output the same to a DC link, a DC link capacitor provided for the DC link, an inverter configured to convert the DC power in the DC link to AC power for driving a motor and to output the AC power, a DC voltage detection unit configured to detect a value of DC voltage applied across the DC link capacitor, an AC voltage detection unit configured to detect a peak value of AC voltage on an AC input side of the converter, and a leakage current detection unit configured to detect a leakage current caused by driving the motor, based on the value of DC voltage detected by the DC voltage detection unit and the peak value of AC voltage detected by the AC voltage detection unit.

A motor drive apparatus includes a converter configured to convert AC power inputted by an AC power supply to DC power and to output the same to a DC link, a DC link capacitor provided for the DC link, an inverter configured to convert the DC power in the DC link to AC power for driving a motor and to output the AC power, a DC voltage detection unit configured to detect a value of DC voltage applied across the DC link capacitor, an AC voltage detection unit configured to detect a peak value of AC voltage on an AC input side of the converter, and a leakage current detection unit configured to detect a leakage current caused by driving the motor, based on the value of DC voltage detected by the DC voltage detection unit and the peak value of AC voltage detected by the AC voltage detection unit.

A method for estimating parameters of a direct current machine by Laplace transform performed by a computer system. The method includes establishing a transient model of the DC machine and a transfer function based on the transient mode; transforming the transfer function from the time domain to the frequency domain by the Laplace transform to obtain each of an armature current and a rotational speed of the DC machine as a function of frequency; expressing the armature current and the rotational speed as polynomial fractions by polynomial regression, and comparing the functions of the frequency and the polynomial fractions to output values of the armature resistance, the armature inductance, the back electromotive force constant, the moment of inertia and the friction coefficient. As such, the accuracy and operational efficiency in estimating the parameters of the DC machine can be improved.

A power supply device for an internal combustion engine, using a generator driven by an internal combustion engine as a power source and supplying power to a first load that needs to be constantly driven to cause the internal combustion engine to operate and a second load that is permitted not to drive during startup of the engine, wherein a first generation coil for driving the first load and a second generation coil for driving the second load are provided to be magnetically-coupled tightly in the generator, and voltage supplied to a load is boosted to a higher voltage value than conventionally achieved by performing chopper control of an energizing current of the first generation coil and an energizing current of the second generation coil while preventing energization from the second generation coil to a load.

A rotating electrical machine control device is applied to a system including a power conversion circuit electrically connected to a rotating electrical machine, and a capacitor electrically connected to an input side of the power conversion circuit. The rotating electrical machine control device includes a determination unit that determines a switching mode of the power conversion circuit in which a ripple current flowing through the capacitor is reflected, based on an operating area of the rotating electrical machine, and an operation unit that operates the power conversion circuit such that the switching mode of the power conversion circuit is the switching mode determined by the determination unit.