Abstract: A mild-hybrid energy storage system architecture is provided, comprising: a battery; an ultracapacitor connected in parallel with the battery; a passive battery pre-charge circuit connected between a terminal of the battery and a DC bus; a battery main contactor connected in parallel with the battery pre-charge circuit between the terminal of the battery and the DC bus; a passive ultracapacitor pre-charge circuit connected between a terminal of the ultracapacitor and the DC bus; an ultracapacitor main contactor connected in parallel with the ultracapacitor pre-charge circuit between the terminal of the ultracapacitor and the DC bus; and a control module configured to independently control operation of the battery pre-charge circuit, the battery main contactor, the ultracapacitor pre-charge circuit and the ultracapacitor main contactor.

Abstract: A compressor control device, a method for controlling a compressor, and a refrigerator including the same are provided. The compressor control device controls the compressor to be driven using a mode in which the compressor is selectively driven by an inverter and a mode in which the compressor is driven directly using a supply voltage, according to a quality of the supply voltage, a loss which is caused by use of the inverter reduced or removed by directly providing the supply voltage to the compressor within a predetermined voltage or frequency range, and an increased energy efficiency by reducing power consumption.

Abstract: When a control device of an electric automobile carries out fixing control for fixing the energization or cut-off of semiconductor switches in each of at least one switching cycle, at least one cut-off control is implemented among a first cut-off control for cutting off both a power generation path and a power charging path of one power system, and a second cut-off control for cutting off all of the power generation paths or the power charging paths of all the power systems. When only the first cut-off control is implemented, the energization or the cut-off of the semiconductor switches is controlled so that the number of power systems, implementing the first cut-off control is N?1 {N being an integer of at least 2 representing the number of power supplies and semiconductor switches}.

Abstract: Standby power supplies for patient tables need frequent replacement of the lead-acid batteries on which they depend. We propose to feed the emergency power direct to the drive motors, subsequent to the control circuitry. This will reduce the load on the standby power system, allowing greater design freedom to select longer-lasting or less expensive energy stores.

Abstract: The invention relates to a drive circuit for an electric motor having an aerodynamic support of the motor shaft, wherein the drive circuit comprises at least one storage means for storing electrical energy by which the electric motor can be fed with electrical energy on a failure of the supply voltage or intermediate circuit voltage to obtain a minimum speed of the motor shaft required for the air support at least at times.

Abstract: The present invention relates to a device (100) and a method for supplying an electric drive (101) with electric current. For this purpose, three DC/DC converters (102, 103, 104) are provided for coupling at least two connectable electric energy sources (105, 106) to the electric drive (101). The DC/DC converters (102, 103, 104) can be coupled in such a way that direct coupling of each individual one of the at least two electric energy sources (105, 106) to the electric drive (101) is formed via an individual one of the three DC/DC converters (102, 103, 104).

Abstract: An electric storage system includes a charger which supplies power from an external power source to an electric storage apparatus and supplies power of the electric storage apparatus to an external device. A first and a second system main relay allow connection between a positive electrode terminal and a negative electrode terminal of the electric storage apparatus and a load, respectively. A third system main relay is connected in series with a current limiting resistor and, together with the current limiting resistor, is connected in parallel with the first system main relay. A first and a second charge relay allow connection between the positive electrode terminal and the negative electrode terminal of the electric storage apparatus and the charger, respectively. A third charge relay is connected in series with the abovementioned current limiting resistor and, together with the current limiting resistor, is connected in parallel with the first charge relay.

Abstract: A system includes a retarder in electrical communication through an electric link with an alternator, and a controller that compares a power measurement with an accessory load on a system during a retard event, and can reduce an electrical load on the alternator, or can remove all electrical loads from an engine, when electric power that is generated from the retarder is measured to be greater than an accessory load on the system. The system may include an alternator that provides a motor function to rotate a shaft coupled to an engine that is mechanically coupled to one or more mechanically drivable accessories. The alternator powers the mechanically drivable accessories in place of or in addition to the engine.

Abstract: Disclosed is a charger including a first rectifying portion that rectifies an alternating power and outputs the rectified power to a neutral point of a 3-phase motor; a second rectifying portion/inverter that charges output power of the first rectifying portion in a high-voltage battery in a charging mode and drives the 3-phase motor by switching the charged power of the high-voltage battery in a drive mode; a high-voltage charging controller that controls the first rectifying portion and second rectifying portion/inverter so as to charge the high-voltage battery in the charging mode; and a DSP (Digital Signal Processor) that controls the second rectifying portion/inverter so as to drive the 3-phase motor in the drive mode, and controls the high-voltage charging controller so as to charge the high-voltage battery in the charging mode.

Abstract: A robot which is able to complete all or a part of desired operations and take a safety countermeasure in order to prevent an unexpected result from being obtained, even when a power source of a motor-based robot is unintentionally and suddenly cut off. A method of controlling a robot, which includes a main power source, a subsidiary power source and a motor to receive power from at least one of the main power source and the subsidiary power source, includes driving the motor using power supplied from the subsidiary power source if power supplied from the main power source is cut off, selecting at least one of a plurality of safety control modes to stably control the robot in consideration of a current state of the robot, and controlling the robot to operate in the selected safety control mode.

Abstract: An integrated drive motor (IDM) power distribution architecture utilizes an IDM power interface module (IPIM) to create a control voltage that is distributed to all the IDMs in a network. This power distribution may be accomplished along a hybrid cable, for example, that includes both signal conductors and power conductors. The IPIM is capable of detecting short circuits and/or overload conditions and disabling the power supply to the IDMs. Additionally, a second power supply may be utilized in the IPIM such that when the power supply to the IDMs is deactivated, the IPIM may remain functional, for example, to report one or more fault conditions to the user. Additionally, this reporting of fault status may be accomplished via a user display integrated with or coupled to the IPIM.

Abstract: In a control unit for a robot, an inverter which drives a motor installed in a robot. A control circuit controls drive of the motor. A drive power circuit supplies DC power to the motor, and a control power circuit DC power to the control circuit. A backup power circuit supplies backup DC power to the control circuit when the DC power from the control power circuit to the control circuit is shut down. A first switch is arranged between the backup power circuit and the inverter, the first switch being selectively switched on and off to open and close. A first switch control section switches on the first switch such that the DC power in the backup power circuit is supplementarily supplied to the inverter when the motor is driven to be accelerated.

Abstract: A MG drive computer switches off system relays when a collision or a possibility of collision is detected. The computer also executes the revolution speed reduction control for reducing the revolution speed of a rotating electric machine and the discharge control for discharging a smoothing capacitor. In the revolution speed reduction control, the second control for switching on switching elements of three phases of an upper arm or lower arm of an inverter and switching off all other switching elements is performed when the revolution speed of the rotating electric machine is equal to or less than a second threshold. When the revolution speed is higher than the second threshold, the first control for switching on a switching element of one phase of the upper arm or lower arm and switching off other switching elements is performed.

Abstract: An inverter/charger integrated device is provided. The inverter/charger integrated device includes: a three-phase motor; a rectifying unit configured to rectify AC power for charging a battery and output the rectified AC power to a neutral point of the three-phase motor; a rectifier/inverter integrated unit configured to be connected to the rectifying unit and charge the battery; and a control unit configured to control the charging of the battery and an operation of the three-phase motor.

Abstract: A voltage determination device includes a reference voltage generation circuit; a determination target voltage line; a first voltage line; a second voltage line; and a switching circuit disposed between the first voltage line and the second voltage line. The switching circuit is provided for performing a switching operation according to a level of the determination target voltage. The voltage determination device includes a determining circuit for determining the level of the determination target voltage, and a control unit is provided for controlling a level of an electric current flowing between the first voltage line and the second voltage line. The control unit controls a resistivity between the switching circuit and the second voltage line so that the level of the electric current is maintained at a specific level when the determining circuit determines the level of the determination target voltage.

Abstract: The present invention relates to an electrical device for charging accumulator means (5), said electrical device comprising: a motor (6) connected to an external mains (11); an inverter (2) connected to the phases of said motor (6); and switching means (4) integrated into the inverter (2), said switching means (4) being configured to permit said motor (6) to be supplied and to permit the accumulator means (5) to be charged by the inverter (2). According to the invention, said electrical device further includes, for each phase of said motor (6), an RLC low-pass filter (18) connected, on the one hand, to the mid-point (16) of the phase of said motor (6) and, on the other hand, to ground.

Abstract: The maximum electrical power drawn from an electrical power source by a mining excavator comprising electric motors is reduced by supplying supplementary electrical power from an electrical energy storage unit. The input electrical power drawn by the mining excavator is cyclic. An upper limit is set for the electrical power drawn from the electrical power source. When the input electrical power drawn by the mining excavator exceeds the upper limit, electrical power is supplied by the electrical energy storage unit, such as an ultracapacitor bank. The ultracapacitor bank may be charged by the electrical power source during off-peak intervals. Electrical power generated by electrical motors operating in a regeneration interval may also be recaptured and stored in the electrical energy storage unit.

Abstract: There is provided a controller for a steering device that makes it possible to prevent sudden ceasing of steering assisting power by effectively utilizing an auxiliary power source. An electric power steering device that generates steering assist force by a motor includes a battery for supplying electric power to the motor, an auxiliary power source that supplies the motor with electric power, and a control circuit for controlling a power supply to the motor. In the event of a breakdown of the battery, the control circuit adjusts a power supply to the motor from the auxiliary power source according to an amount of energy remaining in the auxiliary power source so as to reduce steering assist force.

Abstract: A motor system includes detecting a duration of idle stop by an idle stop end state detection unit when the idle stop mode of the fuel cell ends; estimating recovery time taken for total voltage of the fuel cell to reach voltage at the idle operation by a fuel cell stack total voltage recovery time estimation unit based on the detected duration; and correcting and reducing a changing rate of the drive motor request torque by the drive motor request torque reduction correction unit based on the estimated recovery time.

Abstract: A control device configured with a first control portion controls an engagement pressure of a first engagement device to make a rotational speed of the input member equal to a predetermined rotational speed during the specific electric power generation control. A second control portion controls an engagement pressure of the second engagement device in such a manner as to make a transfer torque capacity of the second engagement device equal to a predetermined transfer torque capacity during the specific electric power generation control. Another control portion determines a target rotational speed in such a manner as to maintain a state in which an electric power generation amount achieved by the rotating electrical machine coincides with a predetermined target electric power generation amount, in accordance with a magnitude of a differential torque as a difference between a torque transmitted via the first engagement device.

Abstract: The present invention relates to an electric device for driving mechanical equipment comprising an alternating current motor and an inverter, the said inverter comprising, for each phase of the said motor, an H bridge structure comprising four switching elements distributed over two branches connecting two terminals of the said H bridge structure and intended to supply the winding of the said at least one phase of the motor, the said winding being a winding with a mid point and the said electric device being characterized in that it also comprises, for each phase of the said motor, an energy storage unit, in particular a supercondenser, connected, on the one hand, to the mid point of the winding of the concerned phase of the motor and, on the other hand, to a terminal of the H bridge structure supplying the said winding.

Abstract: The discharge control device for a power conversion system performs discharge control to discharge a capacitor parallel-connected to the input side of the power conversion system including a plurality of pairs of high-side and low-side switching elements connected in series and each controlled by a drive unit, by turning on the high-side and low-side switching elements of one of the pairs at the same time. At this time, the discharge control device inhibits an ON command from being inputted to the drive units for the high-side and low side switching elements of the other pairs.

Abstract: An integrated motor drive and battery recharge apparatus includes a battery, an electric motor having N separate motor windings each having a first and a second leg, a contactor having a plurality M of poles, each pole having a first side and a second side, the inverter having 2N switching poles and a capacitor each coupled in parallel with the battery, and PWM control circuitry configured to control the state of each switching pole. Each leg of each motor winding is coupled to a phase node of a corresponding inverter switching pole, at least two of the motor winding legs (or taps thereof) are coupled to the corresponding first sides of the contactor poles, a power source/sink is coupled to the corresponding second sides of the contactor poles, and in one aspect a capacitor is coupled between each pair of contactor poles.

Abstract: An electrical on-board network of a vehicle, having at least two power circuits and an electrical machine allocated to a drive of the vehicle. The electrical machine has at least two phase systems, connected to a respective inverter, and that at least one of the phase systems is capable of being electrically connected to at least one of the power circuits via the associated inverter. A method for operating an electrical on-board network of a vehicle is also described.

Abstract: Power conversion equipment includes an electric power converting section that converts DC electric power to multiphase AC electric power and feeds the converted multiphase AC electric power to a multiphase AC motor. A first short-circuit section includes a first switch disposed between a first DC power supply and the electric power converting section. A second short-circuit section includes a second switch disposed between at least one of an electric power feeding section and the electric power input section in the first DC power supply, or between a multiphase AC output point of the electric power converting section and the multiphase AC motor. A switch control section controls the first switch and the second switch such that the first and second switches are prevented from being brought into the closed-state simultaneously.

Abstract: A secondary-control-system power supply line is provided to supply electricity from a secondary power supply apparatus to an electronic control apparatus. When a primary power supply voltage becomes equal to or lower than a primary power supply determination voltage, a power supply control section turns a step-down switching element on and off to thereby supply electricity from the secondary power supply apparatus to the electronic control apparatus. When a secondary power supply voltage becomes equal to or lower than a secondary power supply determination voltage, the power supply control section turns a secondary power supply relay off so as to stop the supply of electric power from the secondary power supply apparatus to a motor drive circuit, and continues the supply of electric power to the electronic control apparatus. Thus, resetting of a microcomputer of the electronic control apparatus, which would otherwise occur due to a drop in the power supply voltage, is prevented.

Abstract: The present invention is directed to methods for forming an inverter circuit for operating a drive motor of an electric vehicle, which can more effectively reduce the switching noise generated by a power module during the operation of an inverter.

Abstract: The maximum electrical power drawn from an electrical power source by a mining excavator comprising electric motors is reduced by supplying supplementary electrical power from an electrical energy storage unit. The input electrical power drawn by the mining excavator is cyclic. An upper limit is set for the electrical power drawn from the electrical power source. When the input electrical power drawn by the mining excavator exceeds the upper limit, electrical power is supplied by the electrical energy storage unit, such as an ultracapacitor bank. The ultracapacitor bank may be charged by the electrical power source during off-peak intervals. Electrical power generated by electrical motors operating in a regeneration interval may also be recaptured and stored in the electrical energy storage unit.

Abstract: A motor system includes a drive motor configured to generate a drive force using power supplied from a fuel cell; an idle control unit configured to operate the fuel cell intermittently between an idle operation mode and an idle stop mode; a state detection unit configured to detect a state of the fuel cell when the idle stop mode of the fuel cell ends; a recovery time estimation unit configured to estimate a recovery time taken for total voltage of the fuel cell to reach voltage at the idle operation based on the state of the fuel cell detected by the state detection unit; and a control unit configured to perform a correction control for torque of the drive motor based on the recovery time estimated by the recovery time estimation unit.

Abstract: In one embodiment, a power cell chamber for a drive system includes moveable and fixed portions. The moveable portion includes a rectifier stage to rectify an input signal received from a secondary winding of a transformer to provide a rectified signal and an inverter stage having a plurality of switching devices to receive a DC signal and output an AC signal. This moveable portion can be slidably adapted within a cabinet of the drive system. In turn, the fixed portion includes a DC link having at least one capacitor to receive the rectified signal and provide the DC signal to the inverter stage.

Abstract: A method for operating an electric machine with a driver system is provided, in which an operating variable of the electric machine and/or of the driver system is monitored. The validity of the input variables is checked with regard to their checksum and whether the input variables are up-to-date, and the permissibility of an actual moment (Mist2) of the electric machine depending on the operating state of the electric machine is checked. In case of invalid input variables or invalidity of the actual moment (Mist2), a fault reaction is initiated. In addition, the implementability of the planned change of rotary speed is checked and, in case of non-implementability, changed over into a more favorable mode of operation of the electric machine. An electric machine used as a starter/generator in a motor vehicle can be monitored.

Abstract: A drive system is provided for a utility vehicle and includes an alternating-current (AC) motor for providing a drive torque. An AC motor controller receives a battery voltage signal, throttle pedal position signal, brake pedal position signal, key switch signal, forward/neutral/reverse (FNR) signal, and run/tow signal indicative of the utility vehicle being configured to be driven and being configured to be towed. The AC motor controller generates an AC drive signal for the AC motor, wherein the AC drive signal is based on the battery voltage signal, throttle pedal position signal, brake pedal position signal, key switch signal, FNR signal, and run/tow signal.

Abstract: A propulsion system is provided that includes an electric drive, a first energy storage system electrically coupled to the electric drive through a direct current (DC) link, and a second energy storage system electrically coupled to the electric drive. The propulsion system further includes a multi-channel bi-directional boost converter coupled to the first energy storage system and to the second energy storage system such that the second energy storage system is decouplable from the DC link, wherein the second energy storage system comprises at least one battery coupled in series with at least one ultracapacitor.

Abstract: A method for providing electrical energy to an actuator is disclosed. In at least one embodiment, the method includes having a first voltage (UBUS) from a data bus; ii) converting the electric current to a current having a second voltage that is higher than the first voltage; iii) storing electrical energy of the second electric current; and discharging the stored electrical energy to an actuator. A device is also disclosed for providing electrical energy to an actuator.

Abstract: Systems and methods are provided for charging energy sources with a rectifier using a double-ended inverter system. An apparatus is provided for an electric drive system for a vehicle. The electric drive system comprises an electric motor configured to provide traction power to the vehicle. A first inverter is coupled to the electric motor and is configured to provide alternating current to the electric motor. A first energy source is coupled to the first inverter, wherein the first inverter is configured to provide power flow between the first energy source and the electric motor. A second inverter is coupled to the electric motor and is configured to provide alternating current to the electric motor. A rectifier is coupled to the second inverter and configured to produce a direct current output. The second inverter is configured to provide power from the rectifier to the electric motor.

Abstract: Systems and apparatus are provided for an inverter system for use in a vehicle having a first energy source and a second energy source. The inverter system comprises an electric motor having a first set of windings and a second set of windings. The inverter system further comprises a first inverter coupled to the first energy source and adapted to drive the electric motor, wherein the first set of windings are coupled to the first inverter. The inverter system also comprises a second inverter coupled to the second energy source and adapted to drive the electric motor, wherein the second set of windings are coupled to the second inverter. A controller is coupled to the first inverter and the second inverter to achieve desired power flow between the first energy source, the second energy source, and the electric motor.

Abstract: This invention provides a device for preventing sway of a suspended load, which does not require complex calculation for eliminating frictional resistance components. The device is equipped with a speed control device (14) for outputting a torque command based on a speed command, a torque command filter (16), and a load torque observer (4) for estimating the load torque, and configured to output a value obtained by adding a load torque estimation signal to an output of the torque command filter (16). The device is further equipped with a high-pass filter (32) for outputting a signal TRFLHPF in which a frictional resistance component is eliminated from the load torque estimation signal and a sway angle calculator (33) for outputting a sway angle estimation calculated value ?e obtained by multiplying a sway angle calculator factor by the output signal TRFLHPF.

Abstract: A drive device having at least one electric motor that inputs and outputs motive power includes: a plurality of capacitors; a plurality of relays for capacitors that connects and disconnects the motor and the capacitors; and a relay control device that controls the relays for capacitors. The relay control device controls the plurality of relays for capacitors so that during a system start-up, a part of the plurality of relays for capacitors are connected, that is, a partially-on-state is established, after a first predetermined condition is satisfied during the partially-on-state, the part of relays for capacitors are disconnected and a remaining part of the plurality of relays for capacitors are connected, and after a second predetermined condition is satisfied during the remainder-on-state, all the plurality of relays for capacitors are connected.

Abstract: A controller able to efficiently operate an electric motor of an axial air-gap type as an electric motor and an electricity generator is provided.

Abstract: A motor driving apparatus comprises a charge/discharge control circuit for controlling charge to or discharge from a capacitor connected in parallel in a link section between a converter and an inverter, and a current control means for controlling discharge current from the charge/discharge control circuit. The current control means controls discharge current from the charge/discharge control circuit based on input current to the inverter or output current from the converter so that output current from the converter is equal to a prescribed value.

Abstract: In a power supply apparatus, a power supply circuit includes a primary power supply circuit including a high-voltage battery and a step-down circuit for stepping down the voltage of the high-voltage battery, and a secondary power supply circuit including a low-voltage battery and a step-up circuit for stepping up the voltage of the low-voltage battery. The primary power supply circuit and the secondary power supply circuit are connected in parallel. An output voltage of the secondary power supply circuit is set to be lower than an output voltage of the primary power supply circuit. When the output voltage of the primary power supply circuit becomes lower than a target voltage of the secondary power supply circuit, the voltage stepped-up by the step-up circuit is supplied to a motor drive circuit. Accordingly, power supply backup of an electric power steering apparatus can be performed at low cost.

Abstract: The maximum electrical power drawn from an electrical power source by a mining excavator comprising electric motors is reduced by supplying supplementary electrical power from an electrical energy storage unit. The input electrical power drawn by the mining excavator is cyclic. An upper limit is set for the electrical power drawn from the electrical power source. When the input electrical power drawn by the mining excavator exceeds the upper limit, electrical power is supplied by the electrical energy storage unit, such as an ultracapacitor bank. The ultracapacitor bank may be charged by the electrical power source during off-peak intervals. Electrical power generated by electrical motors operating in a regeneration interval may also be recaptured and stored in the electrical energy storage unit.

Abstract: A motorized portable appliance which monitors, and automatically selects, one of multiple power sources. The motorized portable appliance includes an electric motor, a secondary battery and at least one other source of electrical power, and an automatic control to switch between the secondary battery and the other source of electrical power, which may be mains electrical power, an external secondary battery, an on-board secondary battery, an automotive battery, a solar photovoltaic array, or a primary battery. Power conditioning circuitry converts power from the various power sources to a form compatible with the electric motor and recovers remaining power from depleted primary batteries.

Abstract: In a four-wheel drive vehicle, front wheels 14L and 14R are driven by an engine 1, and rear wheels 15L and 15R are driven by an electric motor 5. A high-power alternator 2 is driven by the engine 1, and electric power generated from the alternator 2 drives the motor 5. In addition to controlling the power generation of the high-power alternator 2 and the driving of the motor 5, a 4WD CU 100 estimates an induced voltage E of the motor 5 from a voltage MHV of the motor and from an output current Ia of the high-power alternator, and estimates a rotating speed Nm of the motor from estimation results on the induced voltage E.

Abstract: Methods and systems are provided for operating an electric motor having at least one winding coupled to first and second power supplies. A torque command for the electric motor is received. A present power reserve for the first and second power supplies is determined based at least in part on the torque command. An operating voltage for the second power supply is determined based on the present power reserve. The operating voltage for the second power supply is applied to the at least one winding. The application of the operating voltage allowing the present power reserve to flow between the first and second power supplies and the motor.

Abstract: A power supply device for an electric motor, operated either in a normal operating mode and/or an emergency operating mode, in particular, for an actuator in a motor vehicle and a method for operation of an electric motor in a normal operating mode and/or an emergency operating mode, in particular, for an actuator in a motor vehicle. The electric motor is powered by AC in the normal operating mode and by DC in the emergency operating mode, in particular, in a fault situation.

Abstract: A system and method for operating, or electrically communicating with, an electrical supply network are disclosed. A vehicle is coupled to the electrical supply network, a trigger causes a partial discharge of an electrical energy storage device of the vehicle into electric power network, discharging electrical energy into the electric power network from the vehicle.

Abstract: Switching device for linking various electrical voltage levels in a motor vehicle, in which a drive voltage level has an electric drive machine which may be actuated by a power converter, and a drive energy accumulator which is associated with an intermediate circuit, and in which the drive voltage level is connected to a vehicle electrical system voltage level by an electrical converter. The electrical converter is designed as a coupling circuit which is connected at the drive side to at least one node point of a winding circuit of the electric drive machine and to a voltage potential relative to the intermediate circuit. The coupling circuit is connected at the vehicle electrical system side to the vehicle electrical system via a switching unit which has at least one non-diminishing, finite impedance.

Abstract: According to an aspect of the invention, a motor drive circuit includes a first energy storage device configured to supply electrical energy, a bi-directional DC-to-DC voltage converter coupled to the first energy storage device, a voltage inverter coupled to the bi-directional DC-to-DC voltage converter, and an input device configured to receive electrical energy from an external energy source. The motor drive circuit further includes a coupling system coupled to the input device, to the first energy storage device, and to the bi-directional DC-to-DC voltage converter. The coupling system has a first configuration configured to transfer electrical energy to the first energy storage device via the bi-directional DC-to-DC voltage converter, and has a second configuration configured to transfer electrical energy from the first energy storage device to the voltage inverter via the bi-directional DC-to-DC voltage converter.

Abstract: A propulsion system is provided that includes an electric drive, a first energy storage system electrically coupled to the electric drive through a direct current (DC) link, and a second energy storage system electrically coupled to the electric drive. The propulsion system further includes a multi-channel bi-directional boost converter coupled to the first energy storage system and to the second energy storage system such that the second energy storage system is decouplable from the DC link, wherein the second energy storage system comprises at least one battery coupled in series with at least one ultracapacitor.