Abstract: A method for diagnosing the linkages of an inverter including a controller connected to switching devices that are between a DC input and a multi-phase output. The inverter can be diagnosed to determine whether the control signals provided to the switching devices are being properly provided to the inverter and whether the inverter is operating properly. Diagnosis of the inverter is advisable upon commissioning or after completion of a repair. The controller can provide at least one signal to the switching devices and the signal can be monitored adjacent to the switching devices to ensure that the switching devices are receiving the correct signals from the controller. The controller can provide at least one signal to the switching devices and the output of the inverter can be monitored to determine whether the inverter operates in accordance with the provided signal.

Abstract: An apparatus monitors performance of a power inverter to detect malfunctions. A first signal indicates the direction that electric current exists between a first voltage bus and an output terminal of the power inverter. A second signal indicates the direction that electric current exists between a second voltage bus and the output terminal. A third signal indicates the direction that electric current occurs between the output terminal and a load. Other signals designate a commanded conductivity of switches that control the current within the power inverter. A controller analyzes the values of those signals to determine whether a malfunction has occurred.

Abstract: A method is provided for measuring the torque of an AC motor (4) without a mechanical transducer by sensing input voltage, and input current regardless of phase, and determining the torque therefrom.

Abstract: The control system has application to polyphase AC wound rotor motor which employ opposed parallel connected phase controlled thyristors together with series connected fixed resistors in each leg of a delta connected secondary impedance network. The line-to-line secondary terminals of the motor provide a source of polyphase variable frequency and variable amplitude AC reference signals. The variable frequency, variable voltage reference signals are converted into complementary pairs of square wave synchronization voltages. These same reference voltages are also concurrently integrated during their respective positive and negative half cycles to provide complementary pairs of constant peak amplitude, variable frequency voltages which are combined with associated ones of the aforementioned synchronization voltages to provide synchronization locks.