摘要:
A converter circuit has a reactor connectable to an AC power supply. It further has a PWM converter circuit connected to the reactor, the PWM converter circuit including a high speed diode, a rectifier diode and a switching element connected in parallel to the rectifier diode. The converter circuit further has an input current detector for detecting an input current of the PWM converter circuit, a DC voltage level detector for detecting an output voltage of the PWM converter circuit, a voltage polarity detector connected to the AC power supply, and a control device. The control device measures a variation period of the output voltage measured by the voltage level detector to judge a power supply frequency. It then controls the PWM converter circuit based on a power supply frequency judgement result, a detection result from the voltage level detector, an input current detected by the input current detector, and an output voltage detected by the DC voltage detector.
摘要:
In a motor control apparatus of the present invention, a control section which receives an input voltage to an inverter circuit, a motor current flowing to a brushless motor and a motor current command value indicating the value of a current required to flow to the inverter circuit, and controls the inverter circuit by maintaining a phase of the voltage applied to the brushless motor when the value of the input voltage to the inverter circuit is smaller than the value of a voltage required to be applied to the brushless motor.
摘要:
The present invention provides a power supply apparatus which can suppress a raising and hunting of output (DC voltage) to a load which is light. The power supply apparatus comprises an AC-to-DC converter for supplying a load with a DC voltage, and a switching operation controller for correcting a power factor and controlling a switching element so that an output or a DC voltage of the AC-to-DC converter becomes a predetermined target value. The switching operation controller has a low-pass filter for smoothening the DC voltage with a variable cut off frequency. By varying the cut-off frequency of the low-pass filter, it is possible to recognize a rising of the DC voltage to suppress and stabilize a boost and hunting of the DC voltage in a light load state.
摘要:
A converter circuit for converting an output voltage from an AC power supply includes a rectifier circuit for rectifying the output voltage of the AC power supply; first and second capacitors connected in series, for smoothing the output of the rectifier circuit; and a switch circuit for switching the connections between the respective capacitors and the AC power supply so that the output voltage of the AC power supply is applied to each of the respective capacitors at a cycle that is shorter than the cycle of the AC power supply.
摘要:
A converter circuit for converting an output voltage from an AC power supply includes a rectifier circuit for rectifying the output voltage of the AC power supply; first and second capacitors connected in series, for smoothing the output of the rectifier circuit; and a switch circuit for switching the connections between the respective capacitors and the AC power supply so that the output voltage of the AC power supply is applied to each of the respective capacitors at a cycle that is shorter than the cycle of the AC power supply.
摘要:
A converter circuit for converting an output voltage from an AC power supply includes a rectifier circuit for rectifying the output voltage of the AC power supply; first and second capacitors connected in series, for smoothing the output of the rectifier circuit; and a switch circuit for switching the connections between the respective capacitors and the AC power supply so that the output voltage of the AC power supply is applied to each of the respective capacitors at a cycle that is shorter than the cycle of the AC power supply.
摘要:
A converter circuit for converting an output voltage from an AC power supply is provided with a rectifier circuit for rectifying the output voltage of the AC power supply; first and second capacitors connected in series, for smoothing the output of the rectifier circuit; and a switch circuit for switching the connections between the respective capacitors and the AC power supply so that the output voltage of the AC power supply is applied to each of the respective capacitors at a cycle shorter than the cycle of the AC power supply.
摘要:
A press machine die unit replacing device for replacing die units in a press machine may include a die unit storage device controllably rotatably disposed on a position adjacent to a press machine and having various types of replacement die units that are placed thereon, and a transferring mechanism that is capable of transferring the die units between the die unit storage device and the press machine. The die units selected by controllable rotation of the die unit storage device are capable of being carried in or discharged from the press machine via the transferring mechanism.
摘要:
Disclosed is a semiconductor device which includes: a semiconductor element 200 including a first metal-insulator-semiconductor field-effect transistor 200a and a second metal-insulator-semiconductor field-effect transistor 200b which is connected in parallel with the first metal-insulator-semiconductor field-effect transistor; and a control section which controls the operation of the semiconductor element. The control section controls the semiconductor element so that in a forward direction mode, current flows in a forward direction through the first and second metal-insulator-semiconductor field-effect transistors but that in a reverse direction mode, current flows in the reverse direction through the first metal-insulator-semiconductor field-effect transistor but does not flow through the second metal-insulator-semiconductor field-effect transistor.
摘要:
The object of the present invention is to provide a sound absorbing material having a light weight and excellent sound absorbing performance, and a sound absorbing material consisting of a fiber sheet made of fibers containing at least 50% by mass of a porous fiber having many minute pores, each minute pore opening onto the surface of the porous fiber, and having an airflow resistance in the range of between 0.05 and 3.0 kPa·s/m.The porous fiber having many minute pores, each one opening onto the surface of the porous fiber, has air-permeability, and so a sound absorbing property in itself, and a sheet made of the porous fiber having air-permeability and sound absorbing property has even further sound absorbing properties created by the spaces between the porous fibers, resulting in the sheet becoming a sound absorbing material with extremely great sound absorbing efficiency.