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.

The invention relates to a Z-source inverter grid-connected control method based on single-cycle and double current loop control. LCL is used to filter the grid-connected current, and the grid-connected current loop and capacitor current loop are used for double-loop control, which can effectively suppress The resonance peak of the LCL filter is reduced, and the adverse effect of the resonance peak on the Z-source inverter grid-connected system is reduced. The outer loop of grid-connected current adopts PI controller, and the inner loop of capacitive current adopts P controller, which increases the stability of the system and improves the control accuracy of the system; single-cycle control is used instead of traditional PWM control for Z-source inverter The control of the switch can effectively suppress high-order harmonics; the proposed Z-source inverter grid-connected control scheme with single-cycle control and double current loop control can effectively suppress the influence of the resonance peak value of the LCL filter on system stability. The stability of the system is improved, and the harmonic distortion rate of the grid-connected current is effectively reduced, and the quality of the grid-connected electric energy is greatly improved.

The invention discloses a network access current control method for a single-phase less container load (LCL) filtering grid-connected inverter and belongs to the field of network access current control of a grid-connected inverter. The method comprises the following steps of: feeding back six voltage and current variables which are easily measured in a single-phase LCL filter to obtain 18 feedbacks through proportion, integration and differential, and selecting a proper feedback combination to configure a characteristic equation of an LCL filter grid-connected inverter system transfer function from a third order to a fourth order so as to guarantee that four poles of the configured characteristic equation can be freely configured; further configuring a fourth-order characteristic equationin a form that two poles serve as conjugate poles at fundamental frequency and two poles serve as conjugate poles at resonant frequency; and finally, comparing to acquire various feedback coefficients in the selected feedback combination. By the method, the high gain of a system open loop transfer function on a forward path is achieved, a resonance peak at a natural resonant frequency is effectively suppressed, and the system has good steady state and dynamic responses.

The present invention provides a method, device and medium for designing LCL filter parameters based on the damping ratio. Firstly, according to the traditional LCL filter design method, the converter side inductance and filter capacitor parameters are selected; then, using the damping ratio, the damping resistance and The value of the inductance on the output side is optimally designed; in addition, an iterative optimization scheme for the total inductance and resonance frequency is also provided. The present invention preferably adopts the optimum damping ratio of 0.28, which can ensure the stable operation of the converter system with the LCL filter with the minimum damping loss. The present invention has few design iterations, can guarantee the high-frequency attenuation design of the LCL filter is accurate, avoids the stability risk introduced by unreasonable damping design, and ensures that the selection of current control parameters is simple and direct, and is suitable for high output side voltage of the LCL filter. occasions with low frequency components.