An energy conversion device is provided. The device includes: a reversible pulse width modulation (PWM) rectifier (11) and a motor coil (12), where the motor coil (12) includes at least a first winding unit and a second winding unit, and the first winding unit and the second winding unit are both connected with the reversible PWM rectifier (11). The first winding unit is connected with at least one of neutral lines in the second winding unit, where at least one neutral line of at least one of the winding units is connected with a first end of a first direct current (DC) charging and discharging port (3), the reversible PWM rectifier (11) is connected with a first end of a external battery (2) and a second end of the external battery (2) respectively, and a second end of the first DC charging and discharging port (3) is connected with the second end of the external battery (2).

A power battery heating method for an electric vehicle includes: acquiring a heating power demand of a power battery; acquiring power demand information of a driving module of the electric vehicle in real time, and determining a current heating power of the power battery according to the power demand information; acquiring a compensating heating current according to the heating power demand and the current heating power when the current heating power is less than the heating power demand; causing the motor controller to regulate a control current of the driving motor according to the compensating heating current, so that the driving motor outputs a high-frequency oscillation current equal to the compensating heating current; and causing the power battery to perform self-heating according to the high-frequency oscillation current outputted by the driving motor.

This application provides a powertrain, a coolant flow rate estimation method, and an electric vehicle. Coolant in a first cooling loop of the powertrain is configured to cool an inverter. An electronic pump drives the coolant to circulate in the first cooling loop. When a phase current of a motor is greater than or equal to a preset current value, a controller determines a rotation speed of the electronic pump at a first moment as a first rotation speed, and determines a coolant flow rate at the first moment based on a temperature at a first position in the first cooling loop, a temperature at a second position in the inverter, and a power loss of the inverter. In the solution of this application, data does not need to be separately calibrated for different thermal management systems. This reduces time consumed by data calibration and improves practicability.

Testing connections to phase windings of an electric motor upon startup includes, prior to entering a RUN state in which motor power commands are accepted from a user to perform work, applying to each respective phase of the electric motor a respective test voltage signal, measuring in each respective phase a respective current induced by the respective test voltage signal, and preventing entry into the RUN state when at least one values representative of a respective current is below the respective predetermined threshold.

A propulsion system for a device includes an electric motor configured to generate torque to propel the device. The electric motor includes a stator and a rotor with one or more permanent magnets. A controller is in communication with the electric motor and has recorded instructions for a method for minimizing demagnetization in the one or more permanent magnets. The controller is adapted to select a starting point and an intermediate point on a current trajectory in a stator current graph. The controller is adapted to obtain a final point on the stator current trajectory based on a comparison of the intermediate point and a predetermined voltage limit. A demagnetized torque capability is generated based on the final point on the current trajectory.

A regenerative braking controller for an AC motor. To determine an electromagnetic torque for slowing or stopping the motor, the regenerative braking controller accesses a lookup table to retrieve a braking torque value corresponding to a current estimate of rotor velocity. The retrieved braking torque may correspond to a maximum or minimum torque level at which regenerative braking will occur at the current rotor velocity, or to a torque level at which charging current during regenerative braking will be maximized. If an external mechanical brake is present, the regenerative braking controller can forward an external braking torque signal to a controller so that the mechanical brake can apply the remainder of the braking force beyond that indicated by the regenerative braking torque. A method for establishing the braking torques to be stored in the lookup table is also disclosed.

A regenerative braking controller for an AC motor. To determine an electromagnetic torque for slowing or stopping the motor, the regenerative braking controller accesses a lookup table to retrieve a braking torque value corresponding to a current estimate of rotor velocity. The retrieved braking torque may correspond to a maximum or minimum torque level at which regenerative braking will occur at the current rotor velocity, or to a torque level at which charging current during regenerative braking will be maximized. If an external mechanical brake is present, the regenerative braking controller can forward an external braking torque signal to a controller so that the mechanical brake can apply the remainder of the braking force beyond that indicated by the regenerative braking torque. A method for establishing the braking torques to be stored in the lookup table is also disclosed.

A method includes calculating, for a motor, a voltage constraint and calculating, for the motor, a supply current constraint and a regenerative current constraint. The method also includes calculating, for the motor, a motor current constraint and determining, for the motor, a first operating torque based on the voltage constraint, the supply current constraint, and the motor current constraint. The method also includes at least one of selectively controlling the motor based on the first operating torque and generating information associated with the first operating torque.

An energy conversion device is provided. The energy conversion device includes a reversible pulse-width modulation (PWM) rectifier (102) and a motor coil (103). The motor coil (103) includes L sets of winding units, and each set of winding unit is connected with the reversible PWM rectifier (102), where L≥2 and is a positive integer. At least two sets of heating circuits of a to-be-heated device are formed by an external power supply (100), the reversible PWM rectifier (102), and the winding units in the motor coil (103). The energy conversion device controls the reversible PWM rectifier (102) according to a control signal, so that a current outputted from the external power supply (100) flows through at least two sets of winding units in the motor coil (103) to generate heat, and cause a vector sum of resultant current vectors of the at least two sets of the winding units on a quadrature axis of a synchronous rotating reference frame based on rotor field orientation of the motor to be zero.

A cooperative control method for an energy conversion apparatus is disclosed. The cooperative control method includes: acquiring a target heating power, a target driving power, and a target charging and discharging power; acquiring a first heating power of a motor coil according to the target charging and discharging power; acquiring a second heating power of the motor coil according to the target driving power; adjusting a first quadrature axis current and a first direct axis current to a target quadrature axis current and a target direct axis current when a difference between a sum of the first heating power and the second heating power and the target heating power is not within a preset range, to cause the difference between the sum of the first heating power and the second heating power and the target heating power to be within the preset range; and acquiring a sampling current value on each phase coil and a motor rotor position, and calculating a duty cycle of each phase bridge arm in a reversible pulse width modulation (PWM) rectifier.