94results about How to "Prevent magnetic saturation" patented technology

A high-performance piston core including a first piston cylinder and a second piston cylinder, with a piston center longitudinally disposed between and magnetically coupling the first piston cylinder and the second piston cylinder. The piston center is made of high-performance magnetic material, such as Cobalt steel (CoFe), Silicon steel (SiFe), Vanadium/Cobalt steel (Permendur), alloys thereof, or the like. The high-performance magnetic materials exhibit high magnetic permeability and reduce the magnetic reluctance of flux bottlenecks. In addition, high-performance magnetic materials typically saturate at a higher flux density than the conventional magnetic materials. The first piston cylinder and the second piston cylinder can be made of conventional magnetic material, such as low-carbon steel. The first piston cylinder can include a ring disposed about an end, where the end is longitudinally attached and magnetically coupled to the piston center.

A rotor includes a rotor core with a circumferential surface facing a stator and permanent magnets each received in a corresponding slot of the rotor core. Each of the permanent magnets has a first corner portion positioned closest to the circumferential surface of the rotor core and a first side surface that intersects an imaginary line, faces toward the stator side and makes up part of the first corner portion. The imaginary line extends in the magnetization direction of the permanent magnet through the center of the permanent magnet. Between the first side surface of the permanent magnet and the inner surface of the corresponding slot, there are formed a first gap, a second gap and an abutment area from the first corner portion side in this order. The first gap has a smaller width than the second gap in a direction perpendicular to the first side surface.

A multi-parallel magnetic-filed cancellation type transformer includes a plurality of coils which generate magnetic flux during energization and a core having a plurality of magnetic leg portions on which the coils are wound, and bases for fixing the magnetic leg portions. The plurality of coils are wound on the magnetic leg portions in such a manner that the magnetic flux generated from the coils are formed in the directions opposite to each other. A plurality of closed magnetic circuits of the magnetic flux are formed at the magnetic leg portions and the bases. The magnetic resistance of the closed magnetic circuits is homogeneous. Accordingly, the transformer can reduce the size thereof, and prevent the deterioration of electric power conversion efficiency.

A reactor that can be disposed between stacked coolers, the reactor includes a flat case, a pair of coils, and core material. The pair of coils is (i) located in the flat case, (ii) wound in opposite directions from each other, and (iii) disposed adjacent to each other in a radial direction of the coils. The core material is covering the coils in the flat case.

A sintered ceramic has a porosity of greater than about 30 percent and less than about 80 percent by volume. Pores are filled with an epoxy resin. A filling factor of the epoxy resin is about 40 percent by volume or more. A monolithic ceramic electronic component having an inner electrode, for example, a chip inductor is manufactured with such a porous sintered ceramic. When a direct current is superimposed, the resulting monolithic ceramic electronic component has a substantially unchanged self-resonant frequency and also has a rate of decrease in impedance of about 50 percent or less at 100 MHz.

Provided is a motor driving device that assesses whether a common-mode filter is furnished at the output side of an electric-power conversion device of the motor driving device, and that can also avoid increase in loss of the electric-power conversion device that is due to improvement in the common-mode filter characteristics, and an excessive filter current, and also avoid magnetic saturation at a common-mode choke coil. Provided is a means of assessing the existence of the common-mode filter that is to be connected between the aforementioned electric-power conversion device and the aforementioned motor, by driving the aforementioned switching devices with prescribed PWM ON-OFF driving signals that are in accordance with a carrier frequency of the aforementioned electric-power conversion device, before the real operation; and a means of changing and setting the PWM control method of the aforementioned electric-power conversion device, in accordance with the result of the aforementioned assessment of the existence of the common-mode filter, during real operation.

A motor comprising a stator having a plurality of magnetic poles disposed in a circumferential direction along an outer periphery thereof, a rotor disposed rotatably around the outer periphery of the stator, and a magnet disposed in a circumferential direction along an inner periphery of the rotor. The stator is formed by laminating sheet-like plates. A plurality of the sheet-like plates including an outermost layer of this laminated body comprises a flat portion substantially perpendicular to the magnet, and an extended portion bent to a direction substantially parallel to the magnet. A part of the sheet-like plate having the extended portion disposed to the outermost side is formed into a thickness smaller than thicknesses of the other parts.

A rectifying circuit (18) converts inputted AC power to DC power. An inverter circuit (22) converts the DC power to high-frequency power in accordance with a switching control signal applied thereto from a control circuit (50). A voltage transformer (24) voltage-transforms the voltage of the high-frequency power. An output-side rectifying circuit (40) rectifies the voltage-transformed power. An output detecting circuit (34) detects the magnitude of the voltage of the rectified power, and a signal representative of the detected voltage is applied to the control circuit (50). The control circuit (50) generates such a switching control signal as to make the rectified power have a predetermined value. The value of the voltage from the rectifying circuit (18) is detected by an input detecting circuit (62), and a signal representative of the detected voltage is applied to the control circuit (50). The control circuit (50) controls the operation of the inverter circuit (22) in accordance with the detected voltage representative signal from the input detecting circuit (62) and the saturation magnetic characteristic of the voltage-transformer (24).

A fast-response direct-current current transformer based on multi-sensor fusion is provided and includes: a magnetic modulator, a current correction module, an excitation transformer, an alternating current detection and filtering circuit, a phase-sensitive demodulation and filtering system, a PI controller, and a power amplifier. The current correction module measures a primary current and obtain a feed-forward signal, outputs a false balance state configured to control a magnetic core to quickly exit or avoid entering magnetic saturation after amplifying the feed-forward signal and a PI control signal, and keeps output of the magnetic modulator stable. The magnetic modulator and Hall current sensors are fused in the disclosure, such that the possibility of failure due to a false balance problem caused by saturation of a magnetic core is reduced. After the false balance is generated the magnetic core may be controlled to quickly exit a magnetic saturation state through a feed-forward output current.

Disclosed is a filter circuit that includes means for monitoring currents flowing through positive and negative windings of a common-mode noise filter, and means for performing an adjustment based on the result of monitoring so as to equalize the current flowing positive and negative windings.

In a capacitor charger, a transformer has a primary winding connected between an input voltage and a switch for generating a primary current flowing through the primary winding by switching the switch to thereby induce a secondary current flowing through a secondary winding of the transformer and a secondary voltage tapered from the secondary winding, a control apparatus and method adjusts the on-time period for the switch in response to the input voltage. The charging time and charging current are independent of the input voltage, and there is no power loss resulted from current sense to the primary current.