A motor control device to determine resistance of a stator winding of an AC motor, the motor control device comprising: a circuit having an input connectable to an AC source and an output connectable to an input terminal of an AC motor, the circuit including at least one contactor and at least one solid-state switch connected in parallel to control current flow and terminal voltages in the AC motor, the motor control device further comprising: a controller connected to the circuit and configured to control the at least one contactor and the at least one solid-state switch to selectively operate the motor control device in a plurality of distinct operating modes including a DC injection mode, and wherein during operation of the motor control device in the DC injection mode the controller is configured to: modify switching time of the at least one solid-state switch to create a DC component in an output of the motor control device corresponding to an input to the AC motor, wherein modifying the switching time includes: monitoring an amount of torque pulsation in the AC motor; and control a delay in the switching time of the at least one solid-state switch during operation of the motor control device in the DC injection mode to maintain the torque pulsation within a desired tolerance range; and determine a stator winding resistance of the AC motor based on the DC component of the voltage and current. a controller connected to the circuit and configured to control the at least one contactor and the at least one solid-state switch to selectively operate the motor control device in a plurality of distinct operating modes including a DC injection mode, and wherein during operation of the motor control device in the DC injection mode the controller is configured to: modify switching time of the at least one solid-state switch to create a DC component in an output of the motor control device corresponding to an input to the AC motor, wherein modifying the switching time includes: monitoring an amount of torque pulsation in the AC motor; and control a delay in the switching time of the at least one solid-state switch during operation of the motor control device in the DC injection mode to maintain the torque pulsation within a desired tolerance range; and determine a stator winding resistance of the AC motor based on the DC component of the voltage and current. modify switching time of the at least one solid-state switch to create a DC component in an output of the motor control device corresponding to an input to the AC motor, wherein modifying the switching time includes: monitoring an amount of torque pulsation in the AC motor; and control a delay in the switching time of the at least one solid-state switch during operation of the motor control device in the DC injection mode to maintain the torque pulsation within a desired tolerance range; and determine a stator winding resistance of the AC motor based on the DC component of the voltage and current. monitoring an amount of torque pulsation in the AC motor; and control a delay in the switching time of the at least one solid-state switch during operation of the motor control device in the DC injection mode to maintain the torque pulsation within a desired tolerance range; and determine a stator winding resistance of the AC motor based on the DC component of the voltage and current.