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

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.

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.

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 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 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.