The present disclosure relates to a method for motor thermal overload protection, including: obtaining a motor thermal limit curve; selecting a first and a second overload factor calculation point on the curve, and calculating the first and second overload factors based on a preset heating time constant; calculating a modified overload factor based on the first and second overload factors; selecting at least two time constant calculation points on the motor thermal limit curve, and calculating a modified heating time constant for each time constant calculation point based on the modified overload factor; obtaining a modified heating time function for each motor operating point based on the modified heating time constant for each time constant calculation point; calculating a stator heat level at each motor operating point based on the modified overload factor and heating time function; comparing the stator heat level with the first and second predetermined thresholds.

The present disclosure relates to a method for motor thermal overload protection, including: obtaining a motor thermal limit curve; selecting a first and a second overload factor calculation point on the curve, and calculating the first and second overload factors based on a preset heating time constant; calculating a modified overload factor based on the first and second overload factors; selecting at least two time constant calculation points on the motor thermal limit curve, and calculating a modified heating time constant for each time constant calculation point based on the modified overload factor; obtaining a modified heating time function for each motor operating point based on the modified heating time constant for each time constant calculation point; calculating a stator heat level at each motor operating point based on the modified overload factor and heating time function; comparing the stator heat level with the first and second predetermined thresholds.

A hydraulic fracturing system includes a turbine generator for producing electricity at a well site, the turbine generator producing electrical energy at a voltage. The system also includes an electric pump electrically coupled to the turbine generator and receiving operative power from the turbine generator. The system further includes switch gear arranged between the electric pump and the turbine generator, the switch gear distributing electrical energy from the turbine generator to the electric pump, wherein the voltage remains substantially constant from the turbine generator to the electric pump.

A hydraulic fracturing system includes a turbine generator for producing electricity at a well site, the turbine generator producing electrical energy at a voltage. The system also includes an electric pump electrically coupled to the turbine generator and receiving operative power from the turbine generator. The system further includes switch gear arranged between the electric pump and the turbine generator, the switch gear distributing electrical energy from the turbine generator to the electric pump, wherein the voltage remains substantially constant from the turbine generator to the electric pump.

A motor includes a motor control circuit having a ground terminal, and a current limiting part disposed on a path electrically connecting the ground terminal and an external ground terminal included in an external circuit disposed outside the motor.

A motor includes a motor control circuit having a ground terminal, and a current limiting part disposed on a path electrically connecting the ground terminal and an external ground terminal included in an external circuit disposed outside the motor.

A motor control device controls energization of a motor by interchangeably converting a direct current electric power of a power source and an alternating current electric power of the motor with a power conversion circuit according to a power running operation and a regeneration operation of the motor. A voltage instruction value calculation unit calculates a q-axis voltage instruction value and a d-axis voltage instruction value by feedback control of dq-axis currents. A voltage instruction value limit unit limits at least one of the q-axis voltage instruction value and the d-axis voltage instruction value. The voltage instruction value limit unit performs a q-axis voltage limit prioritize process for limiting the q-axis voltage instruction value over the d-axis voltage instruction value, or a d-axis voltage limit prioritize process for limiting the d-axis voltage instruction value over the q-axis voltage instruction value, during the regenerative operation of the motor.

A motor control device includes an electric current detection result acquisition unit configured to acquire a result of detecting an electric current for operating a motor, an electric current determination unit configured to determine whether or not the electric current acquired by the electric current detection result acquisition unit is greater than or equal to a predetermined threshold value, an operation time setting unit configured to set an operation time period corresponding to the electric current when the electric current determination unit determines that the electric current is greater than or equal to the predetermined threshold value, and an operation control unit configured to perform control for causing the motor to be continuously operated for the operation time period set by the operation time setting unit.

A motor control device includes an electric current detection result acquisition unit configured to acquire a result of detecting an electric current for operating a motor, an electric current determination unit configured to determine whether or not the electric current acquired by the electric current detection result acquisition unit is greater than or equal to a predetermined threshold value, an operation time setting unit configured to set an operation time period corresponding to the electric current when the electric current determination unit determines that the electric current is greater than or equal to the predetermined threshold value, and an operation control unit configured to perform control for causing the motor to be continuously operated for the operation time period set by the operation time setting unit.

A power module for driving a motor includes: a positive bus input voltage terminal; a phase terminal for each motor phase; an inverter including a half bridge for each motor phase, each half bridge including a high-side power switch electrically coupled between the positive bus input voltage terminal and respective phase terminal, and a low-side power switch electrically coupled between the respective phase terminal and ground; a first driver circuit for driving a gate terminal of each power switch; a protection switch electrically coupled in series between the positive bus input voltage terminal and each high-side power switch, and having a greater short-circuit withstand time and a lower short-circuit current level compared to each inverter power switch; and a second driver circuit for turning on the protection switch during normal operation and turning off the protection switch in response to a detected short circuit condition.