Power conversion system and motor control method based on same

A power conversion system comprising:

• a power conversion device configured to supply electric power to a motor;
• and a power supply device configured to supply electric power to the power conversion device,
• wherein the power conversion device includes:
• a power conversion unit configured to convert the electric power;
• a control unit configured to control the power conversion unit;
• and
• a current detection unit configured to detect a current flowing through the power conversion unit,
• wherein the power supply device includes:
• a storage device configured to store electric power in accordance with a voltage;
• a step-up/down power supply circuit configured to change the voltage of the storage device based on a voltage command;
• and
• a computing circuit configured to compute energy stored in the storage device and output it as the voltage command to the step-up/down power supply circuit,
• wherein the control unit includes a memory device in which motor characteristics of the motor are stored in advance, and
• wherein when it is determined by using information from an encoder of the motor and a current value detected by the current detection unit that the motor characteristics correspond to the motor characteristics stored in the memory device, the control unit causes the computing circuit to increase a control command amount for the storage device to temporarily increase the motor characteristics.

A motor control method based on a power conversion system comprising a power conversion device configured to supply electric power to a motor and a power supply device configured to supply electric power to the power conversion device,

• wherein the power conversion device includes a power conversion unit configured to convert electric power, a current detection unit configured to detect a current flowing through the power conversion unit, and a control unit configured to calculate powered drive energy of the motor by using information from the motor and a current value from the current detection unit, and
• wherein the power supply device includes a storage device that is coupled to the power conversion unit and is configured to store electric power in accordance with a voltage, a step-up/down power supply circuit configured to change the voltage of the storage device based on a voltage command, and a computing circuit configured to compute energy stored in the storage device based on the powered drive energy calculated by the control unit and output it as the voltage command to the step-up/down power supply circuit,
• the motor control method comprising:
• a torque determination step of determining whether a torque of the motor is equal to or higher than a predetermined value or not;
• a command value determination step of determining whether the voltage command is in a lowered state or not;
• a velocity deviation determination step of determining whether a velocity deviation difference of the motor is equal to or higher than a predetermined value or not in a predetermined period;
• a velocity command determination step of determining whether an angular velocity of the motor has reached a command velocity or not;
• and
• a voltage assist step of increasing the voltage command when it is determined that the torque exceeds the predetermined value in the torque determination step, when it is determined that the voltage command is in the lowered state in the command value determination step, when it is determined that the velocity deviation is equal to or higher than the predetermined value in the predetermined period in the velocity deviation determination step, and when it is determined that the angular velocity has not reached the command velocity in the velocity command determination step.