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.

A method for determining the status of a robot according to an embodiment includes acquiring first data and second data related to an operation of the robot, acquiring a resonance frequency by analyzing the operation of the robot in a frequency region based on the first data related to the operation of the robot, acquiring a first comparison result by comparing the acquired resonance frequency with a reference resonance frequency, when the first comparison result is a threshold value or more, generating a Lissajous figure by DQ transforming a three-phase signal based on the second data related to the operation of the robot, acquiring a second comparison result by comparing the generated Lissajous figure with a reference Lissajous figure, and determining the status of the robot based on at least one of the first comparison result and the second comparison result.

Provided is a power conversion device that does not require adaptation work and can suppress a current beat regardless of an operation state of a motor. The power conversion device includes an inverter 1 that converts a DC voltage into an AC voltage and drives an AC motor 2, and beat compensation units 46 and 49 that suppress a current beat component of an output current of the inverter 1. The beat compensation units 46 and 49 include beat extraction units 50, 51, and 52 that calculate beat components of the output current of the inverter 1, and beat compensation voltage calculation units 53 and 54 that estimate beat compensation voltages from the beat components calculated by the beat extraction units 50, 51, and 52. The current beat component of the output current of the inverter 1 is suppressed based on the beat compensation voltages estimated by the beat compensation voltage calculation units 53 and 54.

The present application provides a control method, an apparatus, a power system, and an electric vehicle, relating to the field of electric vehicles. The method includes: obtaining a battery cell temperature of a power battery, and sending a first control signal to an inverter when the battery cell temperature meets a preset power battery heating condition, where the first control signal is configured to control the inverter to convert a current provided by the power battery into an alternating current with a randomly changing frequency, and the alternating current with a randomly changing frequency is configured to supply power to a permanent magnet motor. New frequency components may be introduced to evenly distribute originally concentrated radial electromagnetic forces to an entire stator, thereby reducing vibration noises during the heating process of the power battery.

A vehicle driving device is driven by a power unit. A three-phase motor includes a first stator winding and a second stator winding. The first stator winding is connected in parallel to the second stator winding, and the first stator winding and the second stator winding are synchronized with each other. A first current sensor is coupled to the first stator winding for measuring a first-phase current. A second current sensor is coupled to the first stator winding for measuring a second-phase current. A third-phase current of the first stator winding is generated according to a calculating procedure of the first-phase current and the second-phase current. A duty cycle between a first power module and a second power module is controlled according to a feedback compensation of the first-phase current, the second-phase current and the third-phase current.

A power detecting device includes a vehicle driving system, a battery detecting module and a controlling module. A first stator winding and a second stator winding are synchronized and connected in parallel with each other. A first end of a first current sensor is coupled to a first-phase winding end of the first stator winding for measuring a first-phase current. A first end of a second current sensor is coupled to a second-phase winding end of the first stator winding for measuring a second-phase current. The battery detecting module is coupled to a first power supply for measuring a current signal and a voltage signal. A controller generates a first power according to the current signal and the voltage signal and generates a second power according to a plurality of data from a database. The controller compares the first power with the second power to generate a detecting result.

A drive system includes an electric machine with a rotor having an externally excited rotor winding, and a stator having stator winding sets, each with at least three stator windings; a control unit controlling the electric machine supply the rotor winding with a first current signal, and the stator windings with different current phases of a multi-phase second current signal, thus producing a rotary magnetic field generating a torque on the rotor; at least one inverter, the multi-phase current signal being provided based on the at least one inverter; and at least one rectifier providing a DC signal, the first current signal being based at least on the DC signal and on an AC harmonics component. Harmonics of a current phase of the multi-phase current signal are reduced based on the supply of the AC harmonics component.

A method for determining the status of a robot according to an embodiment includes acquiring first data and second data related to an operation of the robot, acquiring a resonance frequency by analyzing the operation of the robot in a frequency region based on the first data related to the operation of the robot, acquiring a first comparison result by comparing the acquired resonance frequency with a reference resonance frequency, when the first comparison result is a threshold value or more, generating a Lissajous figure by DQ transforming a three-phase signal based on the second data related to the operation of the robot, acquiring a second comparison result by comparing the generated Lissajous figure with a reference Lissajous figure, and determining the status of the robot based on at least one of the first comparison result and the second comparison result.

A torque ripple and a position error caused by an offset error of the current sensor affects an electrical angle frequency of a motor. In an apparatus of the present disclosure, a computation device executes a power spectrum computing process when a three-phase alternating current motor is at a constant speed, and a value obtained by subtracting a position command value from a position detected by a position detector is fast Fourier transformed, to compute a power spectrum of a position error signal at the electrical angle frequency. Then, the computation device executes an offset correction computing process, to evaluate the power spectrum and to update an offset correction amount. By repeatedly executing these processes when the three-phase alternating current motor is driven at a constant speed, the torque ripple and position error caused by the offset error are reduced.

Electrical power conversion systems and methods suited for driving electric motors, and related systems such as propulsion systems, and vehicles employing same, are disclosed herein. In an example embodiment, the electrical power conversion system includes a plurality of series coupled inverters, each including respective first and second DC input terminals and also including respective AC output ports by which the inverters can respectively be coupled at least indirectly to motor winding sets. Additionally, the system includes a controller coupled to the inverters and configured to generate control signals that are respectively provided to the inverters. The control signals tend to cause respective AC output powers output from the respective AC output ports to be equal or substantially equal in a manner that tends to result in respective DC link voltage portions applied between the respective DC input terminals of the respective inverters being or becoming equal or substantially equal.