60 results about "Resonance problem" patented technology

The invention discloses a tower drum resonance avoiding and crossing control method of a wind turbine generator and the wind turbine generator, and belongs to the field of wind turbine generator control. The tower drum resonance avoiding and crossing control method comprises the following steps of: monitoring wind wheel rotation frequency f, and comparing the wind wheel rotation frequency f with apreset rotation speed resonance region; setting the rotation speed resonance region as follows: setting a rotation speed resonance region according to inherent frequency ft of a tower drum, wherein the rotation speed resonance region comprises rotation speed lower limit, rotation speed upper limit and a rotation speed area between the rotation speed lower limit and the rotation speed upper limit;and converting ft into rotation speed St, wherein the size of the rotation speed St is within a range from the rotation speed lower limit value Sm and the rotation speed upper limit value Sx; and when the wind wheel rotation frequency is within the rotation speed resonance region, controlling wind wheel rotation speed to quickly rise or drop to pass through the rotation speed resonance region according to a current state of the wind turbine generator. A rotation speed resonance region is set near a crossed joint of wind wheel rotation speed and tower drum inherent frequency, reasonable rotation speed resonance region upper and lower limits are set, and the rotation speed of the wind turbine generator is controlled to quickly rise or drop, so that the wind turbine generator passes throughthe rotation speed resonance region, and therefore, the tower drum resonance problem is solved.

Provided is a novel shielding cable comprising at least one signal line and two metallic conductive shielding tapes covering the periphery of the signal line. The metallic conductive shielding tape is formed by a metallic foil covering a side of a plasticity base material. The metallic foil of the first metallic conductive shielding tape faces outwardly, is spirally wound around the signal line, and defines a plurality of first spiral coils. The metallic foil of the second metallic conductive shielding tape faces inwardly, reversely spirally wound around the first metallic conductive shielding tape, and defines a plurality of second spiral coils. Continuous electrical contact is formed between the first metallic conductive shielding tape and the second metallic conductive shielding tape. The two metallic conductive shielding tapes are wound in a crossed manner such that the metallic foils of the two metallic conductive shielding tapes can be completely and tightly combined and cannot generate periodic breakpoints, thereby guaranteeing continuity of a conductive surface. Thus, a resonance problem generated by periodic fluctuation of shielding conductive surface capacitance is solved and an effect of solving a high-frequency point abrupt attenuation.

The diaphragm of a high fidelity speaker is constituted of framework members, and a member filling between the framework members. The framework member is a flat plate, and all framework members are arranged radially outward from the center of the diaphragm in parallel with the vibrating direction and bonded to each other in the radial center and then bonded to a drive section. The framework member has high rigidity. The filling member is composed of a foamed body. The diaphragm has no skin and thereby has no resonance problem. Sound is radiated from the filling member. A suspension has rod-like members arranged in a line and bonded to the opposite ends of a first leaf spring, wherein second leaf springs are bonded to the opposite ends of the rod-like members at right angles thereto, and the ends of the second leaf springs are bonded to unmovable portions of the speaker. Intrinsic resonance occurring in the suspension is very small and displacement is small in directions other than the vibrating direction. An edgeless flat plate speaker system reproducing a sound with high fidelity with no impact of intrinsic resonance can be constituted using this invention.

The invention provides a hybrid electric vehicle, a motor driving transmission system and a vibration reduction mechanism of the system. A motor driving transmission mechanism comprises a middle shaft, a rotor, a first supporting part, a second supporting part and a vibration reduction element. The first supporting part is used for being connected with the middle shaft, and the second supporting element is used for being connected with the rotor; the vibration reduction element is connected between the first supporting part and the second supporting part and made of a damping material. In the motor driving transmission system, the first supporting part in the vibration reduction mechanism is connected with the rotor of a motor, and the second supporting part is fixedly connected with the middle shaft of the motor driving transmission system. By means of the vibration reduction mechanism, the vibration reduction element can well attenuate high-frequency vibration of the motor driving transmission system, the frequency of the high-frequency vibration is attenuated below the normal rotation speed of the motor, the resonance problem caused by high-frequency vibration is effectively reduced, noise generated by resonance can be reduced, human ears are prevented from being harmed, the situation that the motor, a transmission and other parts are damaged due to resonance is also avoided, and the service life of products is prolonged.