Current control system for LCL type grid-connected inverter and active high-frequency damping method of current control system for LCL type grid-connected inverter

A current control and control system technology, applied in AC network circuits, AC power input conversion to DC power output, electrical components, etc., can solve the problems of digital controller current control gain limitation, etc., to improve stability characteristics and system bandwidth Improve and compensate for delay effects

Active Publication Date: 2019-04-16
XIAN UNIV OF TECH
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Problems solved by technology

[0004] The purpose of the present invention is to provide an LCL type grid-connected inverter current control system and its active high-frequency damping method, which solves the problem that the current control gain of the existing digital controller is limited

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  • Current control system for LCL type grid-connected inverter and active high-frequency damping method of current control system for LCL type grid-connected inverter
  • Current control system for LCL type grid-connected inverter and active high-frequency damping method of current control system for LCL type grid-connected inverter
  • Current control system for LCL type grid-connected inverter and active high-frequency damping method of current control system for LCL type grid-connected inverter

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Embodiment Construction

[0050] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0051] The grid-connected current control system includes the main circuit part and the control circuit part, the main circuit part is as figure 1 The topology shown, including the DC-link voltage v dc , grid voltage v g and the LCL filter together constitute the LCL grid-connected inverter, the DC bus voltage v dc The anode of the switch tube G 1 , G 3 , G 5 The collector is connected, the DC bus voltage v dc The negative pole of the switch tube G 2 , G 4 , G 6 The emitter is connected, the switch tube G 1 , G 3 , G 5 The emitters are respectively connected with the switch tube G 2 , G 4 , G 6 The collector is connected, the switch tube G 2 , G 4 , G 6 The collectors are respectively connected with the inductor L 1a , L 1b , L 1c Connected to one end of the inductor L 1a , L 1b , L 1c The other end of the capacitor C ...

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Abstract

The invention discloses an active high-frequency damping method for current control for an LCL type grid-connected inverter. The active high-frequency damping method specifically comprises the following steps that a current reference value i<L1_ref> on the inverter side and feedback quantity, that is, a predicting current hat{i}<L1> are subjected to subtraction to obtain an error value delta e, and the error value is output by a proportional controller; output signals are divided into three signal flows, one of the signal flows is used as input of a high-frequency damping unit, one of the signal flows is output through a current reconstruction and preset unit part, another one of the signal flows and a common coupling voltage v<pcc> which has a feed-forward coefficient k<g> are subjected to addition, and the sum is output through a time delaying unit; and an output value acts on a controlled object to obtain an output value, that is, an in-grid current i<L2>, the output of the currentreconstruction and preset unit part and the in-grid current i<L2> are subjected to addition, and the predicting current hat{i}<L1> is obtained. A current reconstruction method avoids sampling of a current on the inverter side, reduces the complexity of system hardware, improves invariant features of a system, compensates delay of the system, and reduces dynamic and static errors of the system.

Description

technical field [0001] The invention belongs to the technical field of grid-connected current control, and in particular relates to an LCL type grid-connected inverter current control system and an active high-frequency damping method thereof. Background technique [0002] With the increasing global environmental pollution and fossil energy crisis, the utilization of clean and renewable energy has been widely concerned and developed. Wind energy, solar energy and other non-hydropower renewable energy power generation technologies have become a hot research topic, and the core of new energy power generation grid connection is the grid-connected inverter, which has high requirements for power quality, and grid-connected filters are usually used To reduce switching noise, the LCL filter can filter out the high-order harmonics injected into the grid by the grid-connected inverter. The inductance connected in series with the power grid can also suppress the inrush current, so th...

Claims

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Application Information

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IPC IPC(8): H02J3/38H02J3/01H02M7/5387
CPCH02J3/382H02J3/01H02M7/53871Y02E40/40
Inventor 张琦赵双双张永平孙向东任碧莹安少亮杨惠李尚阔潘存旭
Owner XIAN UNIV OF TECH
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