52results about How to "Limited output power" patented technology

A high electron mobility transistor (HEMT) (10) is disclosed that includes a semi-insulating silicon carbide substrate (11), an aluminum nitride buffer layer (12) on the substrate, an insulating gallium nitride layer (13) on the buffer layer, an active structure of aluminum gallium nitride (14) on the gallium nitride layer, a passivation layer (23) on the aluminum gallium nitride active structure, and respective source, drain and gate contacts (21, 22, 23) to the aluminum gallium nitride active structure.

The present invention provides a method for controlling the output power of a permanent magnet electric motor (102) using a control means (106). The control means (106) includes a means (134) for measuring motor speed (134) and motor phase current (134), and a means for controlling motor phase current (110) to a desired level. A known relationship between motor phase current and motor torque is then employed by a torque controller so that motor shaft torque can be controlled. A power limiting means (128) then limits the output mechanical power of the motor by dividing a limit value of power by the motor speed to produce a maximum allowable torque setting for that speed.

A section of active optical fiber (11) which comprises an active core (1), an inner cladding layer (2) and an outer cladding layer (3). The diameter of said core 91) and the thickness of said inner cladding (2) change gradually along the length of said section of active optical fiber (11). This forms tapered longitudinal profile enabling a continuous mode conversion process along the length of the section of fiber (11). The method for fabricating a section of tapered active optical fiber comprises the steps of fabricating a perform for drawing active optical fiber from said perform, installing said perform into a drawing tower, drawing optical fiber in said drawing tower and altering at least one of the two parameters including the take-off perform speed and the take-up fiber speed during drawing of the optical fiber.

VCSEL diode comprises a bottom electrode (10), conducting substrate material (11), a bottom mirror (12) formed by a multilayer distributed Bragg reflector (DBR) of certain conductivity and reflectivity RA, and an active region (13) comprising a plurality of layers some of which are quantum wells. It also comprises a top mirror (14) formed by a multilayer distributed Bragg reflector (DBR) with reflectivity RB<RA and conductivity of a second type. There are a number of layers (15, 18) which through a process of selective oxidation (exposure to a high temperature wet atmosphere) may be selectively converted to oxide layers, therefore producing well defined internal oxide apertures within the top mirror. There is a high-conductivity semiconductor top contact layer (17), a top electrode layer (19) with a centrally located aperture from which light is emitted, and a trench (16) which defines a mesa type VCSEL. The VCSEL comprises at least one oxide suppression layer in the top mirror whose function it is to suppress high order transverse optical modes.

A high electron mobility transistor (HEMT) is disclosed that includes a semi-insulating silicon carbide substrate, an aluminum nitride buffer layer on the substrate, an insulating gallium nitride layer on the buffer layer, an active structure of aluminum gallium nitride on the gallium nitride layer, a passivation layer on the aluminum gallium nitride active structure, and respective source, drain and gate contacts to the aluminum gallium nitride active structure.

An output power limiter system (PLS) for audio amplifiers may be designed as a feedback control system for protection of the load and / or quality of the audio experience. The PLS may use comparator to sense the output current, compare it to a specified threshold, and assert a signal when the output current reaches and exceeds the specified threshold. The output signal from the comparator may enable a counter that is clocked with a high frequency clock to begin counting to measure the pulse-width of the comparator output. The output of the counter may be averaged through a fast attack and slow release infinite impulse response (IIR) filter having programmable settings to generate a rate of attenuation or rate of release that adjusts a gain correction in terms of decibels (dB). The output of the IIR filter may then be used for attenuating the output current.

A semiconductor laser with an integrated attenuator on the same chip as the laser. In some embodiments the attenuator is formed of the same material as the laser, but without a grating in the attenuator. In some embodiments the laser and attenuator are fabricated concurrently, with the attenuator positioned at the front of the laser and differing from the laser only in not having a grating and having a much smaller length. Level of attenuation by the attenuator is adjustable based on drawing photogenerated current from the attenuator.

A cooling device includes a first cooling medium circuit for circulating a cooling medium that passes through a main body of an engine to a first heat exchanger, a second cooling medium circuit for circulating a cooling medium that passes through the main body to a second heat exchanger, a control valve that is commonly used in the first and second cooling medium circuits, and a control device. The control valve includes a rotatable rotor, and is configured such that a rotation range of the rotor includes a water stop section in which the circuits are both closed. The control device restricts output power of the engine in a period in which the rotation angle is in the water stop section, when the rotor rotates via the water stop section at an operating time of the control valve.

The present invention relates to a self-propelled ground milling machine for treatment of ground surfaces by means of a milling device, a transportation means and a drive device for driving the transportation means and the milling device. The milling device is mounted on a ground milling machine frame and can be switched between a working position, in which the milling device is in operative contact with the ground surface and a maneuvering position, in which the milling device is not in operative contact with the ground surface. The drive device comprises a drive control unit, which controls the driving power of the drive device. The ground milling machine further comprises a ground milling machine control unit. The ground milling machine control unit controls the interaction of the drive device, the transportation means, and the milling device such that the driving power of the drive device in the maneuvering position of the milling device is automatically caused to be lower than the driving power of the drive device in the working position of the milling device while at least sufficient driving power for the transportation means is maintained.

In the present specification, degradation of a battery is suppressed in a hybrid vehicle having an EV mode in which the hybrid vehicle runs without using an engine and an HV mode in which the hybrid vehicle runs using both the engine and a motor. A controller of the hybrid vehicle is configured to limit a usage range of the battery in the EV mode with an execution request of the EV mode having been made by an information input from outside to the vehicle than in the EV mode with no execution request. The degradation of the battery is suppressed by limiting the usage range of the battery.

A communication apparatus which performs wireless communication with other communication devices existing in the neighborhood, includes: a transmission processing element 13 for processing a transmission signal; an antenna 17 for wirelessly transmitting an output of the transmission processing element 13; and an output power regulation element 16 for attenuating the output of the transmission processing element 13 to be output from the antenna 17 when a search signal to search for other communication devices is transmitted in a predetermined state from the transmission processing element 13. With such configuration, when a signal to search for other devices existing in the neighborhood is transmitted in short range wireless communication, a communication range can be restricted using a simple structure.

A discharge lamp ballast is designed to limit or interrupt its AC output power to the discharge lamp upon occurrence of an abnormal discharge outside of an arc tube. A detector is included to examine a lamp voltage once in each of the positive and negative half-cycles or in each one complete cycle of the AC output power, and identifies the abnormal discharge when there is a particular change in the monitored lamp voltage. The particular change may be defined by a single logic or by combination of several logics each designed to represent specific characteristic for the abnormal discharges of several types.

The fuel cell system includes a fuel cell; a power conditioner that converts a cell power supplied from the fuel cell to a power corresponding to a load; a capacitor to which an excessive output power of the fuel cell is charged at the time of a low load operation and from which a power corresponding to the insufficient output power of the fuel cell is discharged at the time of a high load operation; a voltage detection means for detecting a voltage of the capacitor; and a control means that determines the low load operation or the high load operation, calculates an output power from the fuel cell to maintain the excessive power generated at the time of the low load operation within a space capacity of the capacitor, and controls the output power of the fuel cell not to exceed the calculated value.

A discharge lamp ballast is designed to limit or interrupt its AC output power to the discharge lamp upon occurrence of an abnormal discharge outside of an arc tube. A detector is included to examine a lamp voltage once in each of the positive and negative half-cycles or in each one complete cycle of the AC output power, and identifies the abnormal discharge when there is a particular change in the monitored lamp voltage. The particular change may be defined by a single logic or by combination of several logics each designed to represent specific characteristic for the abnormal discharges of several types.

The object of the present invention is to provide a transmitting apparatus and a transmitting power control method that can provide excellent power efficiency and a wide control range of transmitting output power, and a radio communication apparatus employing the transmitting apparatus.At the time of high output power, a high-frequency power amplifier (5) is operated as a nonlinear amplifier, whereby power efficiency when a transmitting signal is power-amplified can be enhanced. Further, at the time of low output power, the high-frequency power amplifier (5) is operated as a linear amplifier, whereby the control range of the transmitting output power can be extended. Still further, when the high-frequency power amplifier (5) is operated as a nonlinear amplifier, by varying the input level of the high-frequency power amplifier (5) according to the average output power of the transmitting signal by the variable gain amplifier (7), it is possible to reduce leak power and to extend the control range of the transmitting output power.

A power converter includes a DC input (26) connected to an inductive element (TR), a switch (T1) arranged to interrupt the inductive current cyclically with a predetermined cycle period, a plurality of load circuits (31, 32, 33), and a multiplexer (36) having a plurality of parallel channels (M1, M2, M3) between first and second output terminals (34, 38) of the inductive element (TR), wherein each channel includes one of the load circuits (31, 32, 33), and the multiplexer is adapted to make the channels conductive sequentially and periodically, and the multiplexer has a switching period that is a multiple of the predetermined cycle period of the switch (T1).

An evaporative cooling type fuel cell system and a cooling control method for the same are provided. The fuel cell system includes a stack that generates electric power by reacting hydrogen as fuel with air as an oxidant. The method includes adjusting an operation pressure of the stack based on a current operation temperature of the stack and adjusting the amount of water supplied to the stack from a water reservoir based on the current operation temperature. The water is supplied to a cathode of the stack. Thus, a compact-simplified fuel cell system is provided, thereby reducing manufacturing costs and weight.

A control system for a hybrid vehicle configured to avoid a sudden and significant reduction in a drive torque generated by a motor during high load operation. A controller comprises a determiner that determines a satisfaction of a predetermined condition, and a power limiter that restricts an upper limit of an output power of an electric storage device supplied to the motor upon satisfaction of the predetermined condition, to a restricted upper limit value which is smaller than a normal upper limit value set in a case that the predetermined condition is not satisfied.

The invention concerns an optical pointing device comprising a coherent light source for illuminating a surface portion with radiation, a driver of the coherent light source for controlling coherent light emissions, a photodetector device responsive to radiation reflected from the illuminated surface portion, processing means for determining, based on the photodetector device response, a measurement of relative motion between the optical pointing device and the illuminated portion of the surface, wherein the coherent light source driver is a fault-tolerant driver comprising redundant power control means for limiting the output power of coherent light emissions.

A control circuit controls a power output module and drives a load device. The control circuit includes a conversion unit, a feed-forward unit, a feedback unit and a control unit. The conversion unit generates a driving signal according to an output signal of the power output module for driving the load device. The feed-forward unit generates a duty cycle reference signal according to the output signal. The feedback unit generates a feedback signal according to the driving signal. The control unit outputs a control signal to control the conversion unit according to the duty cycle reference signal and feedback signal, thereby limiting the output power of the power output module within the maximum power region. A tracking method of the maximum power is also disclosed.

A wireless charging circuit and an abnormal state protection circuit thereof is provided in the present invention. The wireless charging circuit includes a power converter, a resonant circuit and an abnormal state protection circuit. The power converter receives an input voltage for outputting a PWM (pulse width modulation) signal. The input terminal of the resonant circuit receives the PWM signal. The common voltage terminal of the resonant circuit is coupled to a common voltage. The abnormal state protection circuit includes a DC sampling circuit and a control circuit. The DC sampling circuit is coupled to the resonant terminal of the resonant circuit for sampling the DC component of the voltage of the resonant terminal to obtain a DC voltage. The control circuit is coupled to the power converter and the DC sampling circuit for receiving the DC voltage. When the DC voltage is greater than a threshold voltage, the control circuit controls the power converter to reduce the current flowing through the resonant circuit.

System and method for restricting output power from multiple serially coupled DC power sources, such as a solar cell array, controlled by power balancing circuitry, thereby enabling power restriction in the event of an emergency. Output bypass circuitry allows the output voltage to be selectively restricted, and though power for switching between states would be needed, use of bi-stable bypass circuitry would avoid a need for power to remain in a state of bypass operation. Additionally, with the serially coupled DC power sources controlled by power balancing circuitry, use of solid-state current switching elements ensures continued output power restriction due to the clamping action of the body diodes upon the output voltage.

A power supply system includes: a first power circuit having a first battery and a first power line; a second power circuit having a second battery and a second power line; a voltage converter; a power converter; a first voltage acquisition unit which acquires a first closed circuit voltage lower limit CCVmin1 of the first battery; a second voltage acquisition unit which acquires a second closed circuit voltage lower limit CCVmin2 of the second battery; and a power control unit which operates the second power circuit based on a requested power, in which the power control unit isolates the second battery from the second power lines, in a case of a voltage difference between the first closed circuit voltage lower limit CCVmin1 and the second closed circuit voltage lower limit CCVmin2 becoming less than a first voltage threshold value A while output limitation of the second battery is being requested.

A fuel cell system comprising a generation chamber, a plurality of fuel cells arranged in the generation chamber, fuel gas feeding means for feeding a fuel gas to the fuel cells, oxygen-containing gas feeding means for feeding an oxygen-containing gas to the fuel cells, power converter means for converting the DC output of the fuel cells into an alternating current, power control means for controlling the electric power output to the power converter means from the fuel cells, and generation control means for controlling the flow rate of the fuel gas fed to the fuel cells and the flow rate of the oxygen-containing gas fed to the fuel cells. A fuel gas buffer amount specific to the fuel cells is not smaller than a fuel gas amount that is needed within a maximum period of increase-needing time that is necessary until the flow rate of the fuel gas increases to a required amount when the amount of increase in the flow rate of the fuel gas is set to be a maximum. The generation control means sets the flow rate of the fuel gas and the flow rate of the oxygen-containing gas based on an electric current of the fuel cells.