A maximum power tracking method suitable for single-stage grid-connected photovoltaic inverter systems
A maximum power tracking, single-stage technology, applied in photovoltaic power generation, control/regulation systems, and regulation of electrical variables, can solve problems such as inability to distinguish between local maximum power points and global maximum power points, increase implementation complexity, and achieve The effect of reducing the amount of sampling and reducing hardware costs
Active Publication Date: 2016-01-20
HUAZHONG UNIV OF SCI & TECH
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[0005] In addition, the traditional maximum power tracking method usually cannot distinguish between the local maximum power point and the global maximum power point, so additional algorithms, such as the distributed MPPT algorithm based on the particle swarm optimization algorithm, are required to adapt to the working condition of multiple extreme points. Increased implementation complexity on
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[0014] In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.
[0015] figure 1 For the maximum power tracking method described in the present invention, see figure 1 , 101, collect the input photovoltaic array voltage, that is, the photovoltaic array output voltage, and judge whether the photovoltaic array voltage is less than If so, jump to 105; otherwise, jump to 102;
[0016] 102: Determine whether the voltage of the photovoltaic array has increased according to two adjacent sampling values of the photovoltaic array voltage, if so, execute 103, otherwise skip 103 and execute 104;
[0017] 103: Record the current photovoltaic array voltage and grid-con...
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The invention discloses a maximum power tracing method suitable for a single-stage grid-connected photovoltaic inverter system. The maximum power tracing method is characterized by periodically executing the following steps that 1 photovoltaic array output voltage is sampled, whether the photovoltaic array output voltage is lowered to a value below a set critical value is judged, if yes, the steps 2, 3 and 4 are skipped, the step 5 is executed, and otherwise, the step 2 is executed; 2 whether the photovoltaic array output voltage is increased is judged, if yes, the step 3 is executed, and otherwise, the step 3 is skipped and the step 4 is executed; 3 present photovoltaic array voltage and a grid-connected current instruction are recorded; 4 grid-connected current instructions are increased, amplitude limiting is conducted, and the amplitude limiting value is a recorded value in the step 5; 5 present grid-connected current instructions are recorded and decreased; 6 after the grid-connected current instructions run through a current loop, a PWM control signal is obtained, motion of a switching tube is controlled, and maximum power tracing is achieved. According to the method, the sampling quantity is reduced, and the global maximum power point can be traced under the multi-extreme-point working condition.
Description
technical field [0001] The invention belongs to the technical field of new energy, and more specifically relates to a maximum power tracking method applicable to a single-stage grid-connected photovoltaic inverter system. Background technique [0002] Photovoltaic grid-connected power generation system has been widely concerned by researchers because of its advantages such as no pollution. Since the output power of the photovoltaic array varies widely with the weather, it is necessary to use the maximum power tracking technology to maintain the utilization rate of the photovoltaic array at a high level. [0003] The two-stage system is composed of a DC-DC circuit and a DC-AC circuit in series. Usually, the maximum power tracking is realized by the DC-DC conversion link. The DC-AC link generates a grid-connected current command according to the outer ring of the photovoltaic array voltage to maintain the photovoltaic array voltage. constant. Different from the two-stage sys...
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IPC IPC(8): G05F1/67
CPCY02E10/56
Inventor 刘邦银邹常跃段善旭李锐
Owner HUAZHONG UNIV OF SCI & TECH