An electric machine, comprising a power supply and an electrically excited synchronous machine is provided. The electrically excited synchronous machine comprises a stator with stator windings, a rotor, comprising rotor poles with field windings and a plurality of permanent magnets magnetically connected to the rotor pole. A power converter is coupled between the power supply and the electrically excited synchronous machine, the power converter is arranged to provide a pulsed operation by providing a pulsed AC current to the stator windings and a pulsed DC current to the rotor field windings, wherein the pulsed DC current to the rotor field windings causes the rotor poles to have a magnetic orientation that has a same magnetic orientation as the permanent magnets magnetically connected to the rotor poles.

An electric machine, comprising a power supply and an electrically excited synchronous machine is provided. The electrically excited synchronous machine comprises a stator with stator windings, a rotor, comprising rotor poles with field windings and a plurality of permanent magnets magnetically connected to the rotor pole. A power converter is coupled between the power supply and the electrically excited synchronous machine, the power converter is arranged to provide a pulsed operation by providing a pulsed AC current to the stator windings and a pulsed DC current to the rotor field windings, wherein the pulsed DC current to the rotor field windings causes the rotor poles to have a magnetic orientation that has a same magnetic orientation as the permanent magnets magnetically connected to the rotor poles.

The present subject matter is directed to a system and method for improving speed control of a pitch drive system of a wind turbine. In one embodiment, the pitch drive system includes a direct current (DC) motor having an armature and a series-field winding, a battery assembly having a positive terminal and a negative terminal, and a current-controlling device configured in series between the positive terminal of the battery assembly and the series-field winding. The battery assembly is configured to supply power to the pitch drive system and the current-controlling device is configured to supply current to the series-field winding so as to ensure a field flux does not equal zero. Thus, the current-controlling device has the effect of limiting the maximum speed of the DC motor.

The present subject matter is directed to a system and method for improving speed control of a pitch drive system of a wind turbine. In one embodiment, the pitch drive system includes a direct current (DC) motor having an armature and a series-field winding, a battery assembly having a positive terminal and a negative terminal, and a current-controlling device configured in series between the positive terminal of the battery assembly and the series-field winding. The battery assembly is configured to supply power to the pitch drive system and the current-controlling device is configured to supply current to the series-field winding so as to ensure a field flux does not equal zero. Thus, the current-controlling device has the effect of limiting the maximum speed of the DC motor.

A battery system for a vehicle includes: a battery assembly including at least one first battery module and at least one second battery module; a first relay being closed/opened between a first node and one of a first end of the first battery module and a first end of the second battery module being connected to a second end of the first battery module; a second relay being closed/opened between a second node and a second end of the second battery module; a converter converting a voltage between the nodes; a third relay being closed/opened between the converter and the first end of the first battery module; a fourth relay being closed/opened between the first end of the first battery module and a ground; and a battery manager controlling the relays based on a driving condition of the vehicle and energy storage amounts of the modules.

A locomotive, a first chopper circuit, and a second chopper circuit integrating a traction motor with an energy storage device are disclosed. The locomotive includes a prime mover, an energy management device, a DC power bus, a traction motor, an energy storage device, a resistor grid, and a chopper circuit. Each chopper circuit is controlled by the energy management device and includes a plurality of power semiconductors with variable switching frequency. The traction motor may be capable of operating in a motoring mode, where power is controllably supplied by either the prime mover and/or the energy storage device; and a dynamic braking mode, where generated power is controllably allocated to the energy storage device and/or the resistor grid.

A locomotive, a first chopper circuit, and a second chopper circuit integrating a traction motor with an energy storage device are disclosed. The locomotive includes a prime mover, an energy management device, a DC power bus, a traction motor, an energy storage device, a resistor grid, and a chopper circuit. Each chopper circuit is controlled by the energy management device and includes a plurality of power semiconductors with variable switching frequency. The traction motor may be capable of operating in a motoring mode, where power is controllably supplied by either the prime mover and/or the energy storage device; and a dynamic braking mode, where generated power is controllably allocated to the energy storage device and/or the resistor grid.

Disclosed are a method and a system for feedback-controlling including controlling a current supply unit in a controller so that an output applied to a driving unit from the current supply unit is repeatedly turned on/off by predetermined period and duty. The method also includes feedback-controlling of an output value of the controller applied to the current supply unit from the controller so that the output of the current supply unit follows a target value. The feedback-controlling includes an integration control process and stops the integration control process in the period that the current supply unit turns off the output thereof.

Disclosed are a method and a system for feedback-controlling including controlling a current supply unit in a controller so that an output applied to a driving unit from the current supply unit is repeatedly turned on/off by predetermined period and duty. The method also includes feedback-controlling of an output value of the controller applied to the current supply unit from the controller so that the output of the current supply unit follows a target value. The feedback-controlling includes an integration control process and stops the integration control process in the period that the current supply unit turns off the output thereof.

A drive train for a motor vehicle includes an internal combustion engine, a starting device, and a vibration isolation device. The internal combustion engine has a main order of vibration and an excitation frequency predetermined by a predetermined operating principle and a predetermined number of cylinders. The starting device is for starting the internal combustion engine and has an electric machine with a torque characteristic over a speed (n). The vibration isolation device is designed for the main order of vibration of the internal combustion engine. The vibration isolation device has a resonance characteristic below an idling speed (nL) of the internal combustion engine in a resonance range occurring in a first speed range (n2). The resonance range is shifted into a second, lower speed range (n1 when the electric machine is coupled. The electric machine is arranged to supply a torque effective beyond the second, lower speed range (n1.).