Provided is a work machine capable of improving workability. The work machine is provided with: a motor 14; a first power supply unit 180 connected to a battery pack 5 and supplying a boosted power to the motor 14; and a second power supply unit 130 connected to an external AC power supply and supplying a boosted power to the motor 14. The voltage and current of the first power supply unit 180 and the voltage and current of the second power supply unit 130 can be variably controlled by a control circuit 182 and a control circuit 136, respectively. The control circuits 136, 182 perform control so that the power output from the respective first power supply unit 180 and the second power supply unit 130 is combined and supplied to the motor 14.

An electric vehicle propulsion control device includes a power converter that applies an alternating-current voltage to an induction machine and a controller that controls the power converter based on an external operation command. The controller includes a first calculation unit. The first calculation unit calculates, from current information (id and iq) detected at the induction machine and current command values (id*1 and iq*1) that are based on the operation command, a d-axis voltage command (Vd*1) and a q-axis voltage command (Vq*1) for the power converter, and a primary magnetic flux φds and a secondary magnetic flux φdr of the induction machine. The first calculation unit also adds to or subtracts from a term including the q-axis voltage command (Vq*1) an interference term stemming from the d-axis voltage command (Vd*1) in calculating a first speed ω1 that is a free-run speed of the induction machine.

The present disclosure relates to an apparatus for controlling multiple inverters and an inverter system including the same. The apparatus according to the present disclosure determines a motor having the smallest operation time among motors which are not being operated as a main motor to thereby transmit a running reference and a frequency reference to the corresponding main motor, if a speed of a main motor which is being operated is above a speed set by a user and a feedback is below a predetermined level.

In some embodiments, a system of controlling an induction electric motor, includes a command voltage output unit for generating a command voltage for operating an inverter according to a command speed and outputting the generated command voltage to the inverter; a control unit for controlling the command voltage output unit such that the command voltage output to the inverter is compared with an operation limiting voltage and the command voltage is corrected to fall within the operation limiting voltage; and the inverter for controlling the induction electric motor depending on the corrected command voltage. Thus, it is possible to precisely control the induction electric motor even in a high speed operation region by regulating the magnitude of the command voltage applied to the induction electric motor by means of dynamic modulation strategies without the magnetic flux controller.

The invention provides a signal generating method for accurately controlling a motor, the method comprises the steps of generating a period compensation signal and a duration compensation signal, can generate a control signal which is more in conformity with the actual vibration condition of the motor, so that the motor can be controlled more accurately.

In a drive control apparatus for a multiple-winding motor including a power converter for driving a winding group per each winding group of a multiple-winding motor having a plurality sets of winding groups, a compensation amount calculator obtains, by using a signal of a first controller controlling a first power converter driving a first winding group among the winding groups, a compensation amount for compensating a signal of an other controller controlling an other power converter other than the first power converter, based on the compensation amount obtained by the compensation amount calculator. A signal of the other controller is compensated to control the other power converter, and the first power converter is controlled without compensating a signal of a first controller.

A method of monitoring the mechanical condition of a passenger door on a public transit vehicle wherein the door operator is a brushed direct current electrical motor and comprises the steps of: repeatedly recording a profile of the motor current vs. time following initiation of opening or closing of the door; based on previously recorded profiles establishing acceptable ranges of motor current for times following initiation of opening or closing the door; and comparing an instant motor current profile to the acceptable ranges and indicating a potential fault condition if the motor current is outside the acceptable ranges.

An electronic switch control method is disclosed. The method comprises receiving the current working parameters of the electronic switch, then reading duty cycle parameters matching with the current working parameters; conducting a linear calculation with the duty cycle parameters and the working parameters to obtain a new duty cycle; adjusting the current control signal to obtain a PWM signal having the new duty cycle; and controlling the rotation speed of the motor in a load with the PWM signal. By reducing the volume of an electronic switch and achieving a long low-speed travel, the disclosure enables the user to work at an accurate working point with an electronic device.

A method for controlling parallel-connected inverters is provided. The method includes ascertaining a detection scope of a predetermined PWM synchronization signal when a PWM synchronization signal is received, calculating a synchronization error of a PWM carrier at a PWM synchronization signal reception point, and compensating the synchronization error at a peak of the PWM carrier.

A method for controlling parallel-connected inverters is provided. The method includes ascertaining a detection scope of a predetermined PWM synchronization signal when a PWM synchronization signal is received, calculating a synchronization error of a PWM carrier at a PWM synchronization signal reception point, and compensating the synchronization error at a peak of the PWM carrier.