A system including a generator and a controller. The generator includes a permanent magnet generator (PMG), and an exciter. The controller manages operations of the generator. The controller includes an alternating current to direct current (AC-to-DC) converter that generates a direct current (DC) voltage, an exciter drive that provides a DC current to the exciter of the generator using the DC voltage created by the AC-to-DC converter in accordance with the control signal, and a regulator controller that drives the active AC-to-DC converter.

A load driving device includes a smoothing capacitor, an inverter, and a control unit. The inverter includes two legs, each including upper and lower arm switching elements connected in series and converts direct-current power stored in the smoothing capacitor into alternating-current power. The control unit performs voltage drop prevention control for preventing the voltage across the smoothing capacitor from becoming a negative voltage. The control unit stops power running control on the load when the capacitor voltage is higher than the sum of a first voltage and a second voltage. The first voltage is a potential difference between a second terminal and a first terminal in the upper-arm. The second voltage is a potential difference between a second terminal and a first terminal in the lower-arm in the same leg as the leg of the upper-arm.

A method for stabilizing a DC link voltage of an electrical converter, the method including: determining a DC link voltage signal for the DC link voltage of the electrical converter; determining a fluctuation signal of the DC link voltage by applying a high pass filter to the DC link voltage signal; determining a torque offset by multiplying the fluctuation signal with a gain value; and modifying a reference torque with the torque offset for controlling the electrical converter. The gain value is adjusted by: determining a DC link voltage ripple from the DC link voltage signal; and comparing the DC link voltage ripple with a threshold and, when the DC link voltage ripple is higher than the threshold, increasing the gain value.

A motor drive apparatus includes: a rectifier; an inverter; a DC link voltage detection unit; an input current detection unit configured to detect input current inputted to the rectifier; a DC link voltage comparison unit configured to compare a DC link voltage with a first voltage threshold value and with a second voltage threshold value; a current comparison unit configured to compare the input current with a current threshold value; and an abnormality detection unit configured, in a case that the DC link voltage is smaller than the first voltage threshold value or that the DC link voltage is greater than the second voltage threshold value, to determine that a first abnormality has occurred when the input current is smaller than the current threshold value and to determine that a second abnormality has occurred when the input current is equal to or greater than the current threshold value.

The present disclosure provides a system and method that provides active damping at the input of a motor drive system without the need for the hardware used in conventional and RC damping circuits. According to the disclosure a virtual damping network is realised at the input of the motor drive system based on modification of field-oriented control, FOC. More specifically, a control algorithm creates a virtual damping impedance at the motor drive input by applying a damping algorithm to both q and d components of the motor current.

A motor drive apparatus includes a converter which converts AC power into DC power and outputs it to a DC link, an inverter which converts the DC power of the DC link into AC power for driving a motor, DC link capacitors connected in series with each other, resistors connected in parallel with the DC link capacitors and connected in series with each other, a DC link voltage detection unit, a current-carrying element which is connected between one of connection points connecting the DC link capacitors to each other and one of connection points connecting the resistors to each other, and carries a current when the applied voltage is higher than a predetermined value, and a short-circuit judgment unit which judges that at least one of the DC link capacitors has shorted when the DC link voltage value is larger than an upper limit or smaller than a lower limit.

A power converter having a dynamic bus controller to control a rectifier DC output for motoring and regenerating power flow directions, in which the controller controls a DC bus voltage between first and second regenerating voltage limits and limits power at the DC output in an increasing fashion with increasing values of the DC bus voltage according to a regenerating power limit parameter for a regenerating direction of power flow at a DC output. For a motoring direction of power flow at the DC output, the controller controls the DC bus voltage at the DC output between first and second motoring voltage limits and limits the power at the DC output in a decreasing fashion with increasing values of the DC bus voltage according to a motoring power limit parameter.

A control system for a power generation system includes a generator coupled to a turbine via a shaft. The control system includes a memory storing instructions. The control system also includes a processor coupled to the memory and configured to execute the instructions. When the instructions are executed it causes the processor to receive a direct current (DC)-link voltage from an automatic voltage regulator (AVR), wherein the AVR is configured to control voltage characteristics of the generator, and to determine a speed of the generator based on the DC-link voltage.

A device for driving a plurality of motors and an electric apparatus having the same is disclosed. The device includes an inverter connected to a DC terminal, a multi-phase motor connected to the inverter, a single-phase motor serially connected to the multi-phase motor, and a first capacitor and a second capacitor connected in series between a first end and a second end of the DC terminal, wherein the single-phase motor is connected to the multi-phase motor, and a node between the first capacitor and the second capacitor. Accordingly, a plurality of motors serially connected with each other can be driven by using a single inverter.

A device for driving a plurality of motors, including an inverter connected to a DC terminal; a multi-phase motor connected to the inverter; and a single-phase motor serially connected to the multi-phase motor, wherein a number of frequency of current input to the multi-phase motor when driving the single-phase motor and the multi-phase motor at the same speed is smaller than the number of frequency of current input to the multi-phase motor when driving the single-phase motor and the multi-phase motor at different speeds. Accordingly, a plurality of motors can be simultaneously driven at different speeds, by using a single inverter.