Abstract: A power converter for an electric power system comprises a switching circuit (102) for supplying, in a first operating mode of the power converter, voltages for driving a rotating electric machine. The power converter comprises a contactor system (110) and a controller (109) for using, in a second operating mode of the power converter, the switching circuit and at least one of windings (115) of the rotating electric machine as a voltage-decreasing direct voltage converter between direct voltage terminals of the power converter. Therefore, the switching circuit of the power converter can be utilized both for driving the rotating electric machine and, for example, for charging a battery element connected to a direct voltage terminal of the power converter.

Abstract: A working machine comprises a direct voltage source (301), a first power converter (302) for transferring energy from the direct voltage source to electric machines (303a, 303b) driving actuators of the working machine, an electric connector system (304) for electrically connecting to an external power grid, a second power converter (305) for transferring energy from the external power grid to the direct voltage source, and alternating current electric machines (306a, 306b) driving auxiliary devices of the working machine. The electric connector system is suitable for connecting the alternating current electric machines to receive alternating voltage of the external power grid, and the second power converter is suitable for transferring energy from the direct voltage source to the alternating current electric machines. Thus, the electric machines driving the auxiliary devices can be energized directly by the external power grid when the working machine is connected to the external power grid.

Abstract: An electric power system comprises electric energy sources (106-110) and control equipment (101) for controlling the electric energy sources in accordance with a target value of electric power produced by the electric power system. The control equipment activates and deactivates the electric energy sources based on a control value and on activation and deactivation limits. The control value can be the target value or the actual value of the electric power. The control equipment controls active electric energy sources according to the target value and according to power sharing defined for the active electric energy sources. The activation and deactivation limits as well as activation and deactivation order of the electric energy sources can be determined based on properties of the electric energy sources and on a prevailing operational situation of the electric power system.

Abstract: An electric system of an electromechanical power transmission chain is provided that includes a first capacitive circuit, converter equipment between the first capacitive circuit and one or more electric machines, a second capacitive circuit, and a direct voltage converter between the first and second capacitive circuits. The electric system includes a control system for controlling the direct voltage converter in response to changes in first direct voltage of the first capacitive circuit and for controlling the converter equipment in response to changes in second direct voltage of the second capacitive circuit. The control of the first direct voltage is faster than the control of the second direct voltage so as to keep the first direct voltage on a predetermined voltage range and to allow the second direct voltage to fluctuate in order to respond to peak power needs.

Abstract: An electromechanical power transmission chain comprises an electric machine (110) mechanically connectable to a combustion engine (111) and to one or more actuators (114) to be driven, an energy-storage (118) for storing electric energy, converter equipment (115) for driving the electric machine in a torque controlled mode when transferring electric energy between the electric machine and the energy-storage, and a device (101) for producing a torque reference for the electric machine. The device produces a control value based on electric energy stored by the energy-storage so that the control value is a decreasing function of the stored electric energy, and produces the torque reference based on a difference between the control value and a control signal indicative of torque produced by the combustion engine.

Abstract: A bearing housing structure (101) comprises a support section (102) for supporting a bearing (117), a reception interface (103) for receiving lubrication grease, and grease channels (104-106) for conducting the lubrication grease to both sides of the bearing which are mutually opposite in the axial direction of the bearing. The bearing housing structure comprises exit conduits (107, 108) for allowing the lubrication grease to exit the bearing from the both sides of the bearing and a grease reservoir (109) for storing the lubrication grease exiting the bearing via one or more of the exit conduits. The bearing housing structure is capable of operating in different positions so that the axial direction of the bearing can be horizontal, vertical, or slanting.

Abstract: An electric power system includes a direct voltage rail (101), battery elements (102-104) connected with supply-converters (105-107) to the direct voltage rail, and load-converters (111-113) for converting direct voltage of the direct voltage rail into voltages suitable for loads of the electric power system, where the supply-converters and the load-converters are connected with over-current protectors (108-110, 114-116) to the direct voltage rail. The electric power system further includes a capacitor system (117) connected to the direct voltage rail and capable of supplying fault current for switching an over-current protector into a non-conductive state in response to a fault causing a voltage drop at an electrical node connected to the direct voltage rail via the over-current protector. The capacitor system may include one or more high-capacitance electric double layer capacitors. The fault current available from the capacitor system enables a selective protection.

Abstract: A device (101) for producing a position signal indicative of rotational position of a resolver is presented. The device comprises a signal transfer interface (102) for receiving first and second alternative signals, and a processing system (103) for generating the position signal on the basis of the amplitudes of the first and second alternative signals and the polarity of an excitation signal of the resolver. The device is configurable to operate in a first operational mode where a local signal generator (104) generates the excitation signal and the device transmits the excitation signal to the resolver. The device is configurable to operate also in a second operational mode where the device receives information indicative of the polarity of the excitation signal from another device. Thus, devices of the kind described above can be used in a system where many converters are driving separate windings systems of an electrical machine.