68results about How to "Loss and noise" patented technology

An active power factor correction (PFC) circuit and its controlling method are provided. The method comprises the following steps. Drive the power switch of the circuit so that the average inductor current waveform follows the rectified input voltage waveform. Suspend the operation of the power switch at a first moment in a first line cycle of the rectified input voltage and then resume the operation of the power switch at a second moment in a second line cycle of the rectified input voltage. The first moment is when the phase angle of the rectified input voltage exceeds a predetermined angle and the switching frequency of the power switch exceeds a predetermined frequency. The time span from the first moment to the end of the first line cycle is substantially as long as the time span from the beginning of the second line cycle to the second moment.

A bladeless fan assembly for creating an air current includes a nozzle mounted on a base housing a device for creating an air flow through the nozzle. The nozzle includes an interior passage for receiving the air flow from the base and a mouth through which the air flow is emitted. The nozzle extends about an axis to define an opening through which air from outside the fan assembly is drawn by the air flow emitted from the mouth. The nozzle includes a surface over which the mouth is arranged to direct the air flow. The surface has a diffuser portion tapering away from the axis, and a guide portion downstream from the diffuser portion and angled thereto.

In a power switching circuit, a second commutation member has a second commutation path electrically connected in parallel to a first commutation path and a second diode provided in the second commutation path and electrically connected antiparallel to a semiconductor switching element. While the semiconductor switching element is off, the second commutation path allows a second current based on the inductive load to flow therethrough in a forward direction of the second diode within a commutation period. The second diode has a second reverse recovery time shorter than a first reverse recovery time of the first diode. A second inductance of the second commutation path is higher than a first inductance of the first commutation path.

A drive circuit for an insulated gate device includes a constant current source generating a constant current, and a switching circuit, wherein a gate of the insulated gate device is connected to a power supply potential side via the constant current source at the time of turn-on and to a ground potential side at the time of turn-off. Whereby a drive circuit for the insulated gate device can be reduced loss at the time of turn-on and reduced temperature dependency of noise.

A gate driving circuit has a variable current carrying path that switches a current carrying path among a driving target device, a DC power source and a reactor to operate in plural operation modes including at least a hold mode, a preparation mode, and an execution mode. The variable current carrying path includes a backflow path for causing a reactor current flowing through the reactor to flow back to the DC power source when a gate voltage of the driving target device deviates from a preset allowable voltage range. A drive control part sets the operation mode of the variable current carrying path to the hold mode and holds the ON state or the OFF state of the driving target device, and further switches the operation mode in sequence of the preparation mode and the execution mode, and realizes turn-on or turn-off of the driving target device.

An error voltage Verr, as amplified by an amplifier, and an input voltage Vin, are multiplied together by a multiplier to generate a first threshold value signal Vth1, which is in phase with and similar in waveform to the input voltage Vin, and proportional in amplitude to the error voltage Verr. A second threshold value signal Vth2 is generated from the first threshold value signal Vth1 by a series circuit of a diode and a resistor. The power factor is increased by on / off-control of a switching element via a drive circuit, so that a current detection signal Vi, which is detected by a resistor and corresponds to an input current, falls between the two threshold value signals Vth1 and Vth2. Since the off time is not fixed, the noise spectrum is spread and increase of the switching frequency is suppressed. Noise reduction thus can be attained.

In a gate driving circuit, when a driving target device is turned on, an auxiliary driving element is turned on to form a closed circuit comprising a DC power source, a reactor, an auxiliary driving element and an OFF-driving element, and make reactor current flow in the direction from a power source intermediate point to an output point in advance. Just before the driving target device is turned on, the OFF-driving element is turned off to form a resonance circuit comprising the reactor, the auxiliary driving element and the gate capacitance, and make gate current (reactor current) flow so that the gate capacitance is charged by using resonance phenomenon of the resonance circuit.

A system having a redundant topology for communication between one or more devices and a central hub. The system comprises a central hub or switch and one or more end nodes where each end node includes a first port and a second port. A first active cable is connected to the first port in each end node and a first port in the hub and, a second active cable is connected to the second port in each end node and a second port in the hub. Messages are transmitted across both the first and second cables to the first and second ports of the end nodes. The end node performs an integrity check on the messages received over the first and second cables and utilizes the first one to pass the check. Thus, if one cable malfunctions, the end node still is able to receive the message over the other cable without any loss of data.

A sensorless control apparatus of a rotary machine includes an inverter 05 to invert DC power and AC power from one to another, a permanent-magnet synchronous machine 07 whose rotor has magnetic saliency and which receives power from the inverter and is driven thereby, a PWM modulate means 04 to determine an output voltage of the inverter according to a command for controlling the permanent-magnet synchronous machine, a current detect means 06 to detect a current passed to the permanent-magnet synchronous machine, a high-frequency component calculate means 10 to calculate high-frequency components of current changes caused by voltages that have been determined by the PWM modulate means and have been output from the inverter, and a rotational phase angle estimate means 08 to estimate a rotational phase angle of the permanent-magnet synchronous machine according to a spatial distribution of the high-frequency components on rotating coordinate axes synchronized with the rotation of the permanent-magnet synchronous machine. The apparatus is capable of suppressing an increase in loss and noise caused by the sensorless control of the rotary machine and stably operating with simple adjustments.

A resonant power source apparatus has a series circuit of switching elements QL and QH connected to ends of a DC power source, a series circuit of a current-resonant capacitor, a resonant reactor, and a primary winding of a transformer connected to ends of the switching element QL or QH, a rectifying / smoothing circuit to rectify and smooth a voltage of a secondary winding, a pulse ratio controller to alternately turn on / off the switching elements QL and QH according to an output voltage from the rectifying / smoothing circuit, and a resonant period detector to detect a period during which energy is transmitted from the primary side to the secondary side of the transformer. The pulse ratio controller determines an ON period of the switching element according to a signal from the resonant period detector and an ON period of the switching element QH according to a signal from the rectifying / smoothing circuit.

In a power converting apparatus which converts AC power into DC power, an inverter circuit including at least one series-connected single-phase inverter is connected in a downstream of a stage in which an AC input is rectified in series therewith. In the downstream stage of the inverter circuit, there are provided a smoothing capacitor connected via a rectifier diode and a short-circuiting switch for bypassing the smoothing capacitor. The short-circuiting switch is set to an ON state only in each of short-circuiting phase ranges of which midpoint matches each of zero-crossing phases and an output of the inverter circuit is controlled by using a current command so that a DC voltage of the smoothing capacitor follows a target voltage and an input power factor is improved.

A drive mechanism, a massage mechanism and a massage gun are provided and belong to the technical field of power transmission. The drive mechanism includes: a drive motor; a first eccentric wheel, an end surface thereof fixedly connected to an output shaft of the drive motor and another end surface thereof provided with a first eccentric shaft; a drive lever, arranged on a side of the first eccentric wheel facing away from the drive motor and an end thereof being assembled with the first eccentric shaft by a first bearing; a second eccentric shaft, assembled on another end of the drive lever facing away from the first eccentric shaft; a second eccentric wheel, assembled with the second eccentric shaft by a second bearing and an end thereof facing away from the second eccentric shaft being provided with a fixing part; and a transmission piston, pivotally connected with the drive lever.

A drive circuit includes a constant current circuit which supplies a constant current to the gate of an IGBT and on-operates the IGBT; a discharge circuit which grounds the gate of the IGBT and off-operates the IGBT; and a switch circuit which operates one of the constant current circuit or discharge circuit in accordance with a control signal and turns on or off the IGBT. In particular, the drive circuit includes a current detection circuit which detects a current flowing through the IGBT when the IGBT is turned on; and a current regulation circuit which feeds the current detected by the current detection circuit back to the constant current circuit and controls an output current of the constant current circuit in accordance with the turn-on characteristics of the IGBT.

A driver circuit facilitates reducing noises and losses and improving the driving performances thereof without connecting a series circuit of capacitor and a resistor to the gate of IGBT. The driver circuit includes a slope setting circuit that sets the gate voltage waveform of IGBT; and an operational amplifier that includes a non-inverting input terminal, to which an output voltage V* from slope setting circuit is inputted, and an inverting input terminal, to which a divided voltage Vgsf divided by resistors is inputted; and the operational amplifier outputs an output voltage Vout, proportional to the difference between the output voltage V* and the divided voltage Vgsf, to the gate of IGBT.

A power source apparatus includes a DC voltage generator (1, 2, 3) to generate a DC voltage, a plurality of voltage converters connected in parallel with one another and each having a switching element (5a / 5b) to convert the DC voltage generated by the DC voltage generator into a predetermined DC voltage, a first controller 10 to generate a first control signal for controlling ON / OFF of one of the switching elements contained in the plurality of voltage converters, and a second controller 20 to control, according to the first control signal, the switching elements other than the switching element controlled by the first controller.

The present invention provides a three-phase voltage source inverter system capable of obtaining a nearly sinusoidal output waveform while minimizing apparatus size increase and cost increases. The three-phase voltage source inverter system of the present invention is provided with: a three-phase inverter unit INV-M; and an auxiliary circuit 1 inserted between a direct-current power source and the three-phase inverter unit, including: dividing capacitors Cd1, Cd2 dividing a direct-current voltage of the direct-current power source; a single-phase inverter unit INV-A in which 60° ON-periods are set for upper switching elements S7, S8 in each phase of single-phase with an 80° delay, and 60° ON-periods are set for lower switching elements S9, S10 in each phase of single-phase with a 60° delay from the upper side switching elements and with an 80° delay between each phase; and an auxiliary transformer Ta.

An ozone generator includes a transformer, a direct current power supply unit connected to a primary side of the transformer, a reactor connected to a secondary side of the transformer, a semiconductor switch connected between one end of a primary winding of the transformer and the direct current power supply unit, and a control circuit for implementing ON-OFF control of the semiconductor switch at a set switching frequency to thereby apply a voltage to the reactor. The interior of the reactor is set to conditions for making it easy to generate an electric discharge therein.

Provided is an air charging apparatus driven by a rotating magnetic field and compressing or pressurizing and transferring air. The air charging apparatus includes at least one impeller sucking air and giving kinetic energy to intake air; an impeller case leading external air inhaled by the impeller into the impeller and converting velocity energy of air out of the impeller into air having pressure energy to discharge air; and a rotating body accelerator equipped with the impeller and the impeller case and driving the impeller. Here, the rotating body accelerator drives the impeller by generating a torque by interaction with an intake negative pressure, by generating a torque by interaction with the intake negative pressure and using supplied power, or by generating a torque using supplied power.

A switching power-supply device has an inductor, a switching element serially connected to the inductor, a control circuit, which controls on and off of the switching element and performs an output voltage control in any one of a plurality of modes including a continuous mode and a discontinuous mode, and a continuous mode detection circuit, which detects that the output voltage control is performed in the continuous mode when a current flowing through the switching element is equal to or greater than a threshold.

An object is to improve insulation in a bonding layer and to improve a bonding strength of a supporting body and piezoelectric single crystal substrate, in a bonded body having the supporting body made of a polycrystalline material or single crystal material, the piezoelectric single crystal substrate and the bonding layer provided between the supporting body and piezoelectric single crystal substrate.The bonded body includes the supporting body, piezoelectric single crystal substrate and the bonding layer provided between the supporting body and piezoelectric single crystal substrate. The bonding layer has a composition of Si(1-x)Ox (0.008≤x≤0.408).

The invention concerns a motor vehicle air duct also serving as crosspiece forming part of the structure of the vehicle. The invention is characterised in that the duct comprises two half-shells (2, 12) including each a tubular portion (6, 16) and two lateral flanks (4a, 4b; 14a, 14b); it further comprises: two stop elements (22a, 22b) defining each a rib projecting relative to one of the contact surfaces of one of the half-shells and having a stop surface arranged immediately proximate to an abutting surface (40a, 40b) provided on the other half-shell (12), a continuous weld bead (13a, 13b) extending between the contact surfaces of the half-shells which are in contact with each other.

A driver circuit for turning ON and OFF one of two parallel-connected insulated-gate semiconductor elements includes a voltage control circuit that controls a level of a power supply voltage in response to a detected element temperature of the one semiconductor element, a constant current supply section, responsive to a drive signal, for supplying a constant current to a gate of the one semiconductor element to turn the one semiconductor element ON, the power supply voltage being supplied to the constant current supply section from the voltage control circuit, and a discharge circuit, responsive to the drive signal, for discharging an electric charge accumulated in the gate to turn the one semiconductor element OFF.