A method of controlling a coasting torque using an electric motor for a vehicle having the electric motor includes: determining a speed range to travel on a forward slope based on the current vehicle speed; determining a target speed within the speed range based on the coasting torque and a travel load depending on vehicle speed; and correcting a driving force of the electric motor in response to the determined target speed.

The overload relay units within a motor control group have the timing function for their motor thermal memories under the control of a central controller in communication with the overload relays. Thus expensive timing components and control of timestamps can be removed from individual overload relays. Further reduction of individual overload relay components can be accomplished by removing the nonvolatile memory function from the individual overload relays and allowing the central controller to perform the nonvolatile memory functions for the overload relays. The motor thermal model function for the overload relays can remain in the overload relays or might be moved to the central controller if communication bandwidth permits.

A motor control assembly for an electric motor. The motor control assembly is configured to be coupled to the electric motor, and includes a wireless communication module, an input power connector, and an inverter module. The wireless communication module is configured to receive a wireless signal from a system controller. The input power connector is configured to receive a DC voltage from an external power supply module. The inverter module is coupled to the wireless communication module and the input power connector. The inverter module is configured to convert the DC voltage to an AC voltage to operate the electric motor according to the wireless signal.

A method of controlling a coasting torque using an electric motor for a vehicle having the electric motor includes: determining a speed range to travel on a forward slope based on the current vehicle speed; determining a target speed within the speed range based on the coasting torque and a travel load depending on vehicle speed; and correcting a driving force of the electric motor in response to the determined target speed.

The disclosure enables mutual relationships among operation statuses of each motor to be ascertained without using synchronous serial communication between multiple motor control devices. The motor control system is equipped with: a motor driver having a trigger determination part for determining whether or not a trigger condition is satisfied, a trigger notification part for transmitting a trigger notification indicating that the trigger condition is satisfied to motor drivers by asynchronous communication, and a trace result information generation part for causing a storage part to store a trigger data number for identifying operation data when the trigger condition is satisfied; and motor drivers each having a trace result information generation part for causing a storage part to store a slave trigger time at which the trigger notification is received, a trigger data number for identifying operation data corresponding to the slave trigger time, and a master trigger time.

The overload relay units within a motor control group have the timing function for their motor thermal memories under the control of a central controller in communication with the overload relays. Thus expensive timing components and control of timestamps can be removed from individual overload relays. Further reduction of individual overload relay components can be accomplished by removing the nonvolatile memory function from the individual overload relays and allowing the central controller to perform the nonvolatile memory functions for the overload relays. The motor thermal model function for the overload relays can remain in the overload relays or might be moved to the central controller if communication bandwidth permits.

The disclosure enables mutual relationships among operation statuses of each motor to be ascertained without using synchronous serial communication between multiple motor control devices. The motor control system is equipped with: a motor driver having a trigger determination part for determining whether or not a trigger condition is satisfied, a trigger notification part for transmitting a trigger notification indicating that the trigger condition is satisfied to motor drivers by asynchronous communication, and a trace result information generation part for causing a storage part to store a trigger data number for identifying operation data when the trigger condition is satisfied; and motor drivers each having a trace result information generation part for causing a storage part to store a slave trigger time at which the trigger notification is received, a trigger data number for identifying operation data corresponding to the slave trigger time, and a master trigger time.

A motor control assembly for an electric motor. The motor control assembly is configured to be coupled to the electric motor, and includes a wireless communication module, an input power connector, and an inverter module. The wireless communication module is configured to receive a wireless signal from a system controller. The input power connector is configured to receive a DC voltage from an external power supply module. The inverter module is coupled to the wireless communication module and the input power connector. The inverter module is configured to convert the DC voltage to an AC voltage to operate the electric motor according to the wireless signal.