A control method for a grid-connected inverter without an AC voltage sensor
A technology of AC voltage and control method, applied in AC network circuits, irreversible DC power input to AC power output, electrical components, etc., can solve the amplitude and phase deviation, affect the grid-connected current waveform and DC bus voltage Stability and other issues, to achieve good sine degree, improve power quality, and avoid the effect of integral initial value
Active Publication Date: 2019-04-16
GUANGXI UNIV
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In practice, the low-pass filter is generally used instead of the pure integral, but the low-pass filter will inevitably bring about deviations in amplitude and phase, which will affect the stability of the grid-connected current waveform and the DC bus voltage.
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[0033] The specific embodiment of the present invention will be further described below in conjunction with accompanying drawing:
[0034] Such as figure 1 , figure 2 , image 3 , Figure 4 As shown, a method for controlling a grid-connected inverter without an AC voltage sensor is characterized in that it includes the following steps:
[0035] 1), real-time acquisition of three-phase grid-connected current i abc and DC bus voltage u dc , through the three-phase grid-connected current i abc and the three-phase voltage u on the inverter side abc Do Clark transform to get current i αβ and voltage u αβ , where, the inverter side three-phase voltage u abc by the SPWM switching signal s a,b,c and DC bus voltage u dc Synthesis, the calculation formula is: u a,b,c = u dc *s a,b,c ;
[0036]2) Construct an Orthogonal Signal Generator (OSG) by using the third-order generalized integrator (TOGI) which can realize the static error-free tracking of a specific frequency sin...
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A method for controlling a grid-connected inverter without an AC voltage sensor, comprising the following steps: collecting the three-phase grid-connected current i in real time abc and DC bus voltage u dc , Use the AC voltage observer to observe the grid side AC voltage e αβ , Calculate the reactive power Q, obtain the active current command for modulation, and generate the switching signal s for driving the inverter a,b,c , by driving the switch signal of the inverter to control the on-off of the switch tube to realize the control of the inverter, the present invention controls the on-off of the switch tube by driving the switch signal of the inverter to realize the control of the inverter, by applying TOGI ‑OSG constructs an AC voltage observer, which reduces hardware costs and improves the grid adaptability of the inverter under the condition of distributed energy access; avoids the DC deviation of the initial integral value and integral saturation problems in the observation process; due to the filtering of TOGI As a result, the grid-connected current has good sine degree and low harmonic content.
Description
technical field [0001] The invention relates to the technical field of distributed power generation, in particular to a method for controlling a grid-connected inverter without an AC voltage sensor. Background technique [0002] In recent years, renewable energy sources such as wind power and photovoltaics have developed rapidly, and a large number of large-scale wind power and photovoltaic power stations have been established in China. As the penetration rate of distributed renewable energy continues to increase, grid-connected inverters play an increasingly prominent role in traditional distribution networks. In order to efficiently and reliably complete the distributed grid connection of renewable energy and effectively reduce the impact of grid-connected inverters on the grid, it is necessary to solve the impact of the intermittent and random nature of renewable energy on the voltage stability of the access system. In order to achieve grid-connected power and current co...
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IPC IPC(8): H02J3/38H02M7/44
CPCH02J3/382H02M7/44H02M1/0003
Inventor 卢子广林远林靖宇黄太昱张文元张力
Owner GUANGXI UNIV