39results about How to "Suppression of resonance peaks" patented technology

The invention discloses a current double-loop control method based on repeated PR control for a three-phase LCL grid connected inverter. The method comprises a capacitive current feedback control link and a grid connected current control link. The grid connected current outer loop uses repeated PR regulator control and is used for performing high-performance control on the grid connected current. The capacitive current inner loop uses PI regulator control. The output of an inner loop regulator is modulated by SPWM and then drives the operation of the six IGBT switch tubes of a three-phase inverter bridge. The current double-loop control method achieves high-performance control on the grid connected inverter, suppresses the resonance peak of a LCL grid connected filter, and maintains system stability.

The invention relates to a composite vibration isolation device based on particle damping and a memory alloy material. The composite vibration isolation device comprises an elastic part and also comprises a particle damping part and an auxiliary limit vibration isolation part. The particle damping part contains a particle damping chamber, particles and a soft material, and the auxiliary vibration isolation part comprises a memory alloy bar, a laminated plate, rubber and a base plate. The particle damping part can be combined with the auxiliary limit vibration isolation part by virtue of technologies such as welding and bolted connection, and the auxiliary limit vibration isolation part can be connected with the elastic part, a lower base plate and the base plate by virtue of bolts or in a welding manner. By virtue of damping energy dissipation of the particle damping part and hyper-elasticity of the memory alloy bar, the composite vibration isolation device provided by the invention integrates vibration attenuation and energy dissipation into a whole and overcomes the defect that an existing vibration isolator has a poor damping effect when the frequency is lower than 20Hz, and the vibration isolation effect is better enhanced. The composite vibration isolation device provided by the invention is applicable to vibration isolation of a track in the field of track traffic and can be also applied to vibration isolation of equipment foundation or floors of sensitive buildings.

The invention discloses a method for stable control of positive damping reconstruction impedance of a high-voltage direct-current power transmission system. When switching frequency of a rectificationstation is relatively high, through introduction of a virtual resistor, system damping within control bandwidth is enhanced, and direct current side oscillation is suppressed. When switching frequency of the rectification station is relatively low, and direct current side oscillation frequency is beyond the control bandwidth, the virtual resistor turns to show negative resistance property, and system stability is deteriorated. Phase correction is performed on negative resistance beyond bandwidth, and amplitude of the virtual resistor is not changed, thereby effectively improving a damping characteristic of the high-voltage direct-current power transmission system, suppressing oscillation of the system direct current side, and improving system stability.