Disclosed is an AC motor drive (600) for a three phase, 400 Hz., AC induction motor. The application is a constant speed , constant load application. An AC power source with a wide variation in voltage and frequency is rectified to establish a DC bus. A three phase full wave bridge inverter operates on this source. A cascaded sinusoidal reference signal generator (225) generates three sinusoidal voltages 120° phase shifted from one another. These pure sinusoidal reference help reduce harmonic currents. A high PWM frequency is used to operate the power switches of the bridge to reduce current harmonics. The speed regulator (220) generates an error voltage between a speed command voltage and a feedback of DC voltage that is equivalent to the RMS value of the terminal voltage of the motor for speed regulation. The harmonic content of the DC bus current is extracted to provide short circuit protection.

Disclosed is an AC motor drive (600) for a three phase, 400 Hz., AC induction motor. The application is a constant speed , constant load application. An AC power source with a wide variation in voltage and frequency is rectified to establish a DC bus. A three phase full wave bridge inverter operates on this source. A cascaded sinusoidal reference signal generator (225) generates three sinusoidal voltages 120° phase shifted from one another. These pure sinusoidal reference help reduce harmonic currents. A high PWM frequency is used to operate the power switches of the bridge to reduce current harmonics. The speed regulator (220) generates an error voltage between a speed command voltage and a feedback of DC voltage that is equivalent to the RMS value of the terminal voltage of the motor for speed regulation. The harmonic content of the DC bus current is extracted to provide short circuit protection.

A control device capable of suppressing electromagnetic force applied to a motor has a harmonic current calculation section and an operation section. The harmonic current calculation section calculates amplitude and phase of each of harmonic currents to be superimposed over a fundamental current which flows in phase windings of a stator of the motor based on conditions relating to load change of the motor. The operation section generates and transmits instruction signals to an inverter so that the calculated superimposed harmonic currents flow in the phase windings of the stator.

A control device capable of suppressing electromagnetic force applied to a motor has a harmonic current calculation section and an operation section. The harmonic current calculation section calculates amplitude and phase of each of harmonic currents to be superimposed over a fundamental current which flows in phase windings of a stator of the motor based on conditions relating to load change of the motor. The operation section generates and transmits instruction signals to an inverter so that the calculated superimposed harmonic currents flow in the phase windings of the stator.

An information processing apparatus includes an acquisition unit configured to acquire a first phase signal and a second phase signal that are acquired by measuring a rotation of a moving object, and a calculation unit configured to calculate a rotational angle by an iterative calculation so as to satisfy a relational expression bearing an arctangent. The relational expression bearing the arctangent uses a first cosine wave and a second cosine wave at a higher harmonic of the first cosine wave for the first phase signal, and a first sine wave and a second sine wave at a higher harmonic of the first sine wave for the second phase signal. The first phase signal and the second phase signal may, for example, be analog signals having a wave shape.

The invention provides a signal generating method for accurately controlling a motor, the method comprises the steps of generating a period compensation signal and a duration compensation signal, can generate a control signal which is more in conformity with the actual vibration condition of the motor, so that the motor can be controlled more accurately.

The invention provides a signal generating method for accurately controlling a motor, the method comprises the steps of generating a period compensation signal and a duration compensation signal, can generate a control signal which is more in conformity with the actual vibration condition of the motor, so that the motor can be controlled more accurately.

An inverter control method for a hybrid vehicle includes: monitoring a torque command and a motor speed of the vehicle in real-time; determining whether the motor speed is less than a first speed; determining whether an absolute value of the torque command is less than a first torque when the motor speed is less than the first speed; changing a switching frequency to a predetermined frequency when the absolute value of the torque command is less than the first torque; and controlling an inverter operation by generating a pulse-width modulation (PWM) signal with the switching frequency changed to the predetermined frequency.

An inverter control method for a hybrid vehicle includes: monitoring a torque command and a motor speed of the vehicle in real-time; determining whether the motor speed is less than a first speed; determining whether an absolute value of the torque command is less than a first torque when the motor speed is less than the first speed; changing a switching frequency to a predetermined frequency when the absolute value of the torque command is less than the first torque; and controlling an inverter operation by generating a pulse-width modulation (PWM) signal with the switching frequency changed to the predetermined frequency.

In a control apparatus for a power conversion apparatus, a spectrum changing unit changes a spectrum of at least one of bus harmonic components and switch harmonic components so as to meet at least one of a separation condition and a reduction condition. The bus harmonic components are harmonic components superimposed on a voltage of the bus in accompaniment with on-off operations of switches configuring at least one power conversion apparatuses. The switch harmonic components are harmonic components included in a switching pattern of switches configuring the remaining at least one power conversion apparatus. The separation condition is that the frequencies of both harmonic components are separated by a predetermined value or more. The reduction condition is that an amplitude of at least one harmonic component is reduced when the difference between the frequencies of both harmonic components is less than the predetermined value.