3358 results about "Excitation current" patented technology

A photovoltaic system includes a plurality of photovoltaic modules and a DC motor connected to a three-phase generator driven by a shaft. The three-phase generator is connected to a power mains. The electric power supplied to the DC motor by the plurality of photovoltaic modules is repeatedly measured and adjusted, by changing an external excitation current of the DC motor, to the peak power attainable at the current ambient temperature and the current incident solar radiation intensity. The peak power is preferably determined by incrementally changing the excitation current in predetermined time intervals, until the supplied electric power produces a power level which can be regarded as the peak power.

An antenna described herein includes a driven patch that is configured to emit radiation in a broadside direction in response to receiving excitation current, wherein the driven patch has a first radiating edge and a second radiating edge that are approximately parallel to one another. The antenna also includes a reflector element that is configured to reflect radiation emitted from the first radiating edge in a quasi-endfire direction. The antenna can also include two director elements that are configured to direct radiation emitted from the second radiating edge of the driven patch in a quasi-endfire direction.

A switched current temperature sensing circuit (1) comprises a measuring transistor (Q1) which is located remotely of a measuring circuit (5) which applies three excitation currents (I₁,I₂,I₃) of different values to the measuring transistor (Q1) in a predetermined current sequence along lines (10,11). Resulting base/emitter voltages from the measuring transistor (Q1) are applied to the measuring circuit (5) along the same two lines (10,11) as the excitation currents are applied to the measuring transistor (Q1). Voltage differences ΔV_be of successive base/emitter voltages resulting from the excitation currents are integrated in an integrating circuit (36) of the measuring circuit (5) to provide an output voltage indicative of the temperature of the measuring transistor (Q1). By virtue of the fact that the measuring transistor (Q1) is excited by excitation currents of three different values, the effect of current path series resistance in the lines (10,11) on the output voltage indicative of temperature is eliminated. The predetermined current sequence in which the excitation currents are applied to the measuring transistor (Q1) is selected to minimize the voltages in the integrating circuit (36) during integration of the voltage differences ΔV_be.

This invention relates to one gas wheel motor rotor coil shortcut online test method in the test technique field, which comprises the following steps: through online real time collecting motor electrical parameter data and according to one certain work situation motor electrical parameter data to compute normal current theory values by reverse rotor normal current; then computing excitation magnetic current real value and theory value relative bias; the bias difference is as generation motor set to judge whether there is coil short cut fault as dialogue of the shortcut fault.

The invention involving a magnetorheological fluid damping device for automobile suspension system.The magnetic field generator of this damping device consists of permanent magnet and electromagnetic coil.On the top of the damping device,there are guide apparatus and damping regulator,the function of which is that to ensure the damping channel is uniform annular duct and to meet the high-damp requirement in the restoration process and low-damp requirement in the compression process of damper seperately.The current in the electromagnetic coil designs of bi-directional and this controls the magnetic field intersity of the damping channel,decreases the excitation current of the electromagnetic coil,reduces energy consumption and decreases damper fever.On the non-controlling conditions,this damping device has the equivalent characteristics of the traditional shock absorber and can instead the passive shock absorber,after equiping corresponding current controller,this device can regulate the damping characteristics of suspension system,which improves the automobile driving safety and ride comfort.

The invention provides an alternating-current brushless generator fault detection method based on an exciter exciting current. The method comprises the following steps: firstly, measuring the direct-current component and each subharmonic amplitude value of the exciter exciting current of a generator set; and then, detecting whether the generator set generates electrical failures or not with a stator winding turn-to-turn short circuit diagnosis algorithm, a rotor winding turn-to-turn short circuit diagnosis algorithm, an exciter fault diagnosis algorithm and a rotary rectifier fault diagnosis algorithm, wherein the electrical failures comprise stator winding turn-to-turn short circuit, rotor winding turn-to-turn short circuit, exciter rotor winding turn-to-turn short circuit, exciter rotor winding interphase short circuit, open circuit of one diode of the rotary rectifier and short circuit of one diode of the rotary rectifier. According to the LabView development fault diagnosis algorithm, various electrical faults can be detected by measuring the exciter exciting current so as to save measurement points, and various invasive sensors do not need to be installed in the generator. The alternating-current brushless generator fault detection method has good instantaneity, and the on-line detection requirement can be satisfied.

A DC-DC converter of synchronous rectification type is provided which comprises: a current detector (51) for discerning electric current (I_Q1, I_Q2) flowing through a primary side circuit; first and second DC biasing power supplies (53, 54) for producing a bias voltage (V_BS1, V_BS2) higher than voltage corresponding to excitation current through transformer (4); and first and second comparators (55, 57) for activating first and second rectifying MOS-FET (7, 8) when current detector (51) produces the detection voltage (V_DT) over bias voltage (V_BS1, V_BS2) of first and second DC biasing power supplies (53, 54). As each of first and second rectifying MOS-FETs (7, 8) in secondary side circuit is driven synchronously with electric current (I_Q1, I_Q2) flowing through the primary side circuit except excitation current component through transformer (4), the converter can minimize switching loss in each rectifying MOS-FET (7, 8) in secondary side circuit to improve conversion efficiency.

A vehicle motor-generator apparatus based on a field winding type of synchronous machine coupled to a power inverter and a battery, wherein the synchronous machine is controlled to operate as a motor to perform engine starting and thereafter be driven by the engine as an electrical generator, wherein during a short time interval at the commencement of engine starting, the armature winding of the synchronous machine is driven by a current such that magnetic flux is produced by the armature winding acting in the same direction as magnetic flux produced by the field winding, to thereby achieve increased torque during the time when maximum torque is required. In addition, the supplied field current is set at a maximum value during only an initial period when engine starting begins, until the first compression stroke of the engine has been completed, and thereafter set to a reduced value until the completion of engine starting, thereby reducing the amount temperature rise within the field winding during engine starting, while ensuring a sufficiently high value of initial torque.

A stepping motor is driven in both closed-loop and open-loop modes while initiating microstepping after a predetermined threshold velocity has been reached. A feedback device such as an encoder is mounted on the stepping motor shaft and the encoder keeps track of the mechanical position of the rotor. Based on feedback from the encoder, stator phases are activated to maintain a 90° phase advance and produce maximum torque. A lead angle compensation technique is used to advance the motor lead angle, to allow for the excitation currents to reach maximum even at higher speeds. The stepping motor controller employs this strategy in order to produce maximum torque across a wide range of motor speeds and actuator motions.

In a starter for starting an on-vehicle engine, a solenoid is provided to push a pinion gear. The solenoid has an electromagnetic coil composed of a single coil and electrically separated from a motor circuit, a fixed core, and a plunger. Supply of excitation current to the electromagnetic coil allows the fixed core to be magnetized to attract the plunger. Hence, a movement of the plunger results in a push of the movable member toward the ring gear. A switch is provided in the circuit and has a contact, a movable core, and a switch coil functioning as an electromagnet attracting the movable core in response to supply of current to the switch coil. A movement of the movable core results in on/off switching operations of the switch. The switch is allowed to operate independently of the solenoid when both the switch and solenoid are controlled.

A spin-torque oscillator (STO) has a single free ferromagnetic layer that forms part of both a giant magnetoresistance (GMR) structure with a nonmagnetic conductive spacer layer and a tunneling magnetoresistance (TMR) structure with a tunnel barrier layer. The STO has three electrical terminals that connect to electrical circuitry that provides a spin-torque excitation current through the conductive spacer layer and a lesser sense current through the tunnel barrier layer. When the STO is used as a magnetic field sensor, the excitation current causes the magnetization of the free layer to oscillate at a fixed base frequency in the absence of an external magnetic field. A detector coupled to the sense current detects shifts in the free layer magnetization oscillation frequency from the base frequency in response to external magnetic fields.

A transformer unit and a power converting device, which lessen the influence of noise caused by an external magnetic flux, while reducing the temperature dependency of a coupling coefficient, and which transfer signals while insulating a low-voltage and a high-voltage side electrically. Air-core type insulated transformers have a first and second winding of a primary winding as a sending side and a first and second winding of a secondary winding as a receiving side. The windings of the primary winding are connected in parallel and are wound so that the directions of magnetic fields generated by an exciting current oppose each other. The windings of the secondary winding are wound so that electromotive forces to be generated by an external magnetic flux cancel each other, and are connected in series so as to raise the electromotive forces by a signal magnetic flux generated by the primary winding.

In a magnet-exciting rotating electric machine system, a rotor surface has magnetic salient poles and island-shaped magnetic poles alternately in circumferential direction, and the island-shaped magnetic poles are constituted so that magnetic flux coming from an external source does not flow through. A magnetic excitation part magnetizes the island-shaped magnetic poles and the magnetic salient poles collectively in the same direction, and then control a flux amount flowing through an armature. The armature has armature coils that face the magnetic salient pole and the island-shaped magnetic pole simultaneously so that driving torque fluctuation or power generation voltage waveform distortion is controlled. The magnetic excitation part changes magnetization state of a field magnet irreversibly, or changes an excitation current to an excitation coil to control a flux crossing the armature.

A system and method for mapping the sensitivity of MR coils includes a neural network or other computer intelligence trained from sample MR data to determine coil sensitivity profiles or sensitivity normalizations. Once the network is trained, subsequent coil mapping determinations may include fewer mapping acquisitions per coil. The resulting sensitivity map can be used in compensating for B1 inhomogeneities, parallel imaging reconstruction, generating tailored excitation currents for each individual coil, RF shimming, or other processes.

A magnetically controlled welding method with consumable electrode features that a pair of exciting coils for upper and lower electrodes are arranged respectively above and under the workpiece to be welded, and an exciting power supply is used to provide the exciting current to said coils and generate an external vertical magnetic field for controlling and perform the welding to the workpiece protected by active gas or CO2. Its welding apparatus has exciting power supply, exciting unit and water cooling system.

An electric motor (10) has a field pole formed by a field current passing through a field winding (50). A voltage booting converter (120) converts output voltage of a battery (B) and outputs the voltage between a power source line (107) and a grounding line (105). Field winding (50) is electrically connected onto an electric current channel between battery (B) and power source line (107) and formed so that voltage switched by a switching element (Q1) is applied to both ends. A controller (100) controls the field current so as to adjust density of magnetic flux between a rotor and a stator by performing switching control on switching element (Q1) and a switching element (Q3) connected in parallel to field winding (50) and converts the output voltage of battery (B) into voltage in accordance with a voltage command value.

The invention discloses a method and a device for multicell joint optimization under coverage of a cellular mobile communication network. The method disclosed by the invention comprises the steps of: collecting the position information of all base stations in a target area; performing grid partitioning on the target area; measuring propagation loss from each base station to each grid point; traversing combinations of total emission power and antenna electrical parameters and making statistics on an adverse coverage ratio; and selecting a combination enabling the adverse coverage ratio to be minimal, and feeding optimal excitation current to each antenna. The device disclosed by the invention comprises an information collection module, a gridding processing module, a propagation loss determination module, a traversing solving module and a selecting module. According to the invention, by means of optimizing directional diagrams and emission power of array antennas to realize the multicell joint optimization orienting to an actual propagation environment under network coverage, the adverse coverage of an entire target area is minimal; and the method and the device not only can be applied to the multicell joint optimization orienting to the actual propagation environment under the network coverage, but also can be used for singly correcting the adverse coverage of exceptional cells.

A control apparatus for controlling an exciting current of a field winding type dynamo-electric machine having an exciting winding so as to obtain a demanded output thereof comprises an exciting current detecting circuit being configured to detect an exciting current of the field winding type dynamo-electric machine, a rotation speed detecting circuit being configured to detect a rotation speed of a rotor of the field winding type dynamo-electric machine, an output estimating circuit being configured to estimate an output of the field winding type dynamo-electric machine, an exciting current control circuit being configured to correct the exciting current of the field winding type dynamo-electric machine so as to obtain the demanded output and to supply the corrected exciting current to an exciting winding of the field winding type dynamo-electric machine considering a multi-valued functionality of the output of the field winding type dynamo-electric machine with respect to the exciting current.