摘要:
An electrical power system includes an alternating current (AC) power source configured to output an AC signal, a single phase pulse-width modulated (PWM) rectifier coupled to the AC power source and to an electrical load; a DC link capacitor coupled in parallel to the load and the PWM rectifier; and an active ripple energy storage circuit. The active ripple energy storage circuit has a first terminal, a second terminal and a third terminal, the active ripple energy storage circuit being coupled in parallel to the electrical load, the PWM rectifier and the DC link capacitor via the first terminal and the second terminal, the third terminal being coupled to the second terminal, the active ripple energy storage circuit being configured to selectively absorb and discharge at least part of the ripple energy.
摘要:
An electrical power system includes an alternating current (AC) power source configured to output an AC signal, a single phase pulse-width modulated (PWM) rectifier coupled to the AC power source and to an electrical load; a DC link capacitor coupled in parallel to the load and the PWM rectifier; and an active ripple energy storage circuit. The active ripple energy storage circuit has a first terminal, a second terminal and a third terminal, the active ripple energy storage circuit being coupled in parallel to the electrical load, the PWM rectifier and the DC link capacitor via the first terminal and the second terminal, the third terminal being coupled to the second terminal, the active ripple energy storage circuit being configured to selectively absorb and discharge at least part of the ripple energy
摘要:
A method of operating a fuel cell includes the step of selectively connecting and disconnecting the fuel cell to at least one electrical load dependent at least in part upon at least one of a fuel cell voltage, a fuel cell current and a fuel cell temperature.
摘要:
A fuel cell system in accordance with the invention includes a single, central electronic controller (CPU) for controlling at least the Air Handling sub-system, the Reformer sub-system, the Power Electronics sub-system, and the Customer Interface sub-system. The central controller provides a central location for easier serviceability; increases data transport efficiency by eliminating lengthy links between distributed controllers; eliminates the need for multiple mechanical enclosures; allows for controller thermo conditioning in one mechanical enclosure; and reduces parasitic power losses by employing a single power supply.
摘要:
A system for co-generation of electricity combining a hydrocarbon catalytic reformer, an SOFC assembly and a generator driven by a gas turbine. The fuel cell assembly recycles a high percentage of anode exhaust gas into the reformer. Oxygen for reforming is derived from water in an endothermic process. The stack exit temperature is normally above 800° C. DC power from the fuel cell assembly and AC power from the gas turbine generator are directed to a power conditioner. Anode exhaust gas including carbon monoxide and hydrogen is divided into a plurality of portions by which heat may be added to the reforming, gas turbine, and cathode air heating processes. Water may be recovered from the exhaust. A power system in accordance with the invention is capable of operating at a higher total efficiency than either the fuel cell component or the gas turbine component alone.
摘要:
Propulsion control system and method are provided for use in vehicles including a propulsion motor that is powered by a fuel cell. The fuel cell unit produces a compatible voltage for the propulsion motor, thereby removing the need for a dc/dc boost converter. A buck/boost converter and a standard 12 volt battery are used to start the fuel cell. An inverter receives dc electric voltage from the fuel cell and outputs ac electric voltage to the propulsion motor. A vehicle controller receives a voltage input from the fuel cell unit and outputs a current reference to a comparing device. The comparing device compares the current reference from the vehicle controller to an actual current of the fuel cell unit and then outputs a signal to a PI control which outputs a control signal to a fuel cell controller, whereby the power output of the fuel cell is controlled based on the actual current of the fuel cell.
摘要:
An induction motor drive uses direct vector control for zero speed start up. According to the invention, a speed sensorless induction motor is controlled at all speeds, including zero or substantially zero speed, using direct vector control. In order to utilize direct vector control at all speeds, it is necessary to derive accurate stator flux vectors at all speeds. This is accomplished in the present invention by calculating two sets of stator flux vectors in diverse manners. A first set of flux vectors is derived from measured stator terminal voltage quantities, and a second set of flux vectors is derived from measured stator current quantities. The first set of flux vectors is valid at non-zero speed and the second set of flux vectors is valid at substantially zero speed. The direct vector control utilizes one of the two sets of flux vectors in accordance with predetermined criteria indicative of zero and non-zero speed conditions.
摘要:
A DC Link for use with a multi-phase DC to AC converter provides soft-switch opportunities to the main inverter devices only when such opportunities are required. A quasi-resonant rail swings from source to ground potential either with or without the assistance of an auxiliary switch. The quasi-resonant rail swings from ground to source potential with the assistance of an auxiliary switch. Low switch stresses are characteristic in both the main inverter switch devices and the DC link switch devices. Main power is carried predominantly through a DC link switch thereby minimizing power handling requirements of DC link reactive components.
摘要:
An AC to DC power converter comprises an input filter for filtering the alternating current input and an output filter for filtering and smoothing the direct current power output to a load. The output alternating current of the input filter is rectified and electronically switched by buck and boost switching circuits at a frequency much higher than the frequency of the alternating line current input. The rectified line current is sensed and provided to a control circuit which controls the operation of the buck and boost switching such that the power line current will follow a predetermined reference voltage waveform.
摘要:
One embodiment is a packaged device having multiple layers. Another embodiment is a method of forming a packaged device having multiple layers. Conductive layers and insulating layers can be formed with openings exposing semiconductor devices. The semiconductor devices can be wire-bonded to the conductive layers. In some embodiments, parasitic effects and a relative footprint of the packaged device can be reduced.