An inverter system failure is detected on the basis of the currents of respective phases detected by a current detection unit when carrying out switching control in accordance with a first drive mode in which all switching elements on a lower-side arm are switched on and all switching elements on an upper-side arm are switched off, and the currents of respective phases detected by the current detection unit when carrying out switching control in accordance with a second drive mode in which all of the switching elements on the upper-side arm are switched on and all of the switching elements on the lower-side arm are switched off.

A fuel and oil system comprising a fuel pump; an oil pump. A first electric motor controller configured to supply a variable electrical drive. A second electric motor controller configured to supply a variable electrical drive. A fixed electrical drive. The fuel pump is selectively connected to and driven by the first electric motor controller or the second electric motor controller. The oil pump is selectively connected to and driven by the second electric motor controller or the fixed electrical drive.

A control device for a motor is provided that can determine the states of current controllers controlling the current flowing to windings, as well as reducing the load of arithmetic processing. A control device for a motor having windings includes: a main current controller that is connected with a numerical control and controls current flowing to the winding; and sub-current controllers that are connected with the main current controller and control current flowing to the windings, respectively, in which the main current controller: calculates states of the main current controller and the sub-current controllers, compares between the states of the main current controller and the sub-current controllers thus calculated, and determines whether an abnormality is occurring in the main current controller and the sub-current controllers based on a result of comparing between the states of the main current controller and the sub-current controllers.

A system in which the operation of an electric motor is controlled by electronically controlled switches. The system includes the motor having a run winding and a start winding, a heating component, and a motor control subsystem. A control unit closes a first switch to energize the run winding, closes a second switch to energize the start winding, determines based on an amplitude and a lag time of a current flowing through the motor whether the motor has started and is running normally, and if so, opens the second switch to de-energize the start winding and closes a third switch to activate the heating component. The control unit determines whether the motor has started and is running normally by comparing the real time amplitude and lag time of the current to a plurality of stored amplitudes and lag times associated with different operating conditions.

A power tool is configured to receive power from a power supply. The power tool may include a rectifier that may output a rectified signal to a DC power bus. A switching arrangement may operate to deliver electric power from the DC power bus to an electric motor. A switch path may be electrically coupled in parallel with the rectifier on the DC power bus. The switch path includes an auxiliary capacitor in series with a switch and a state of the switch controls a discharging path for the auxiliary capacitor. A switch control circuit may be configured to detect voltage associated with at least one of the AC power supply or the DC power bus and to control state of the switch in accordance with magnitude of the detected voltage.

A motor control device of the present invention supplies a detection current to a motor at predetermined time intervals, detects a voltage between the both ends of a smoothing capacitor when the detection current is supplied, and determines whether a connector is inserted or unplugged based on a change in the voltage between the both ends of the smoothing capacitor. Furthermore, if determining that the connector is unplugged, the motor control device decreases the voltage between the both ends of the smoothing capacitor to or below a defined value by discharging the smoothing capacitor.

A motor control apparatus controlling current feeding and a rotational direction of a motor includes: four bridge-circuit switches between a high and low potential lines; two current feeding line switches connected through the motor between a first and second nodes in series to arrange two parasitic diodes facing each other; a pull-up resistor between the high potential line and a third node; a pull-down resistor between the low potential line and a fourth node to interpose the motor between the third and fourth nodes; a protective diode blocking current; and a fault diagnostic device having: a driver turning on or off the switches; and a voltage determinator determining suitability of a first and second voltages and performing initial fault diagnosis for at least one of the switches.

A synchronization signal generating portion of a transmitter microcomputer generates a synchronization signal that is synchronized with a drive timing of the own microcomputer and also causes to synchronize the drive timing of microcomputers, and transmits to a receiver microcomputer. A timing corrector of the receiver microcomputer is capable of correcting the drive timing of the own microcomputer so as to synchronize with the received synchronization signal, and includes a timing determiner which determines whether the received synchronization signal is normal or abnormal. The receiver microcomputer permits the timing correction if the synchronization signal is determined to be normal in the timing determination, and prohibits timing correction and drives the motor asynchronously with the transmitter microcomputer if the synchronization signal is determined to be abnormal.

A method for operating a three-phase brushless DC motor with a pulse-width modulation controlled electronic commutation in the event of a malfunction. A maximum number (n) of commutation steps, a direction of motor rotation and at least two possible operating end states are specified, and one of the operating end states is chosen. Following indication of a malfunction, the rotor of the brushless DC motor is rotated at the specified maximum number (n) of commutation steps in the specified direction of motor rotation and the brushless DC motor is then set to the operating end state selected.

An inverter includes a positive electrode terminal and a negative electrode terminal, upper-arm switching elements and lower-arm switching elements, and a voltage divider that supplies partial voltages of a voltage between the positive electrode terminal and the negative electrode terminal to a gate and a drain, respectively, of the lower-arm switching element. The lower-arm switching element includes an HEMT. In the voltage divider, the partial voltages are set to turn the lower-arm switching element off when a positive electrode and a negative electrode of a DC power supply are reversely connected to the positive electrode terminal and the negative electrode terminal, respectively.