Topological structure for grid connection of multiple groups of single-phase inversion units
An inverter unit and single-phase inverter technology, which can be applied in the direction of reducing the asymmetry of multi-phase network, eliminating/reducing asymmetry of multi-phase network, and parallel feeding arrangement of single network, which can solve the problem that it is difficult to realize the power of each phase Problems such as matching, difficult energy-saving operation, difficult to maximize energy-saving use mode, etc., to achieve the effect of improving power matching ability and solving three-phase imbalance
Inactive Publication Date: 2018-07-24
WUXI MEIKAI ENERGY TECH
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Problems solved by technology
[0002] At present, in the application of the micro-grid integrated into the three-phase grid, the main source of power generation is new energy such as photovoltaic or wind power. Due to the limitation of the actual installation area and site, the traditional inverter unit with an output power of 3-5KW only has a single-phase inverter device , it is difficult to achieve the matching of the power of each phase. If the electric power of the new energy is less than the load power, it will be transmitted to the power grid against the current. It is difficult for the user of the micro-grid to achieve energy-saving operation.
Even if a three-phase inverter is installed, due to the traditional SVPWM control, the three-phase feedback currents are all required to be consistent, so the efficiency of the inverter device is low, and it is difficult to realize the use mode of maximizing energy saving
[0003] In engineering applications, because it is difficult to accurately judge the load of each phase during installation, even if the load is measured at that time and the single-phase inverter unit is accurately installed on a connection point of a certain item, the short-term standby or working status of some loads cannot be guaranteed. Depending on the actual load variation caused by the difference, there are also situations in which the load is gradually increased or decreased in the actual power grid, which will also cause the load to change between different phases.
[0004] When multiple non-isolated single-phase inverter units are connected to the grid, due to the existence of the inverter bridge arm, the interphase short circuit of the grid may be caused by the opening of the bridge arm
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[0015] The present invention will be further described below in conjunction with the accompanying drawings.
[0016] Such as figure 1 Shown is the high-frequency isolation topology of this patent, which consists of a DC / DC conversion unit, a shared DC bus, a non-isolated inverter unit, a sensor unit, at least one high-frequency isolated inverter unit and at least one control unit Composition, this topology has been isolated from each other after the DC bus, and the isolation transformer uses a high-frequency isolation transformer.
[0017] Such as figure 2 Shown is the low-frequency isolation topology of this patent, which consists of a DC / DC conversion unit, a shared DC bus, a non-isolated inverter unit, a sensor unit, at least one low-frequency isolated inverter unit, and at least one control unit. The topology inverter is then isolated, and the isolation transformer uses a power frequency isolation transformer.
[0018] Such as image 3 The input end of the shown micro...
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The invention discloses a topological structure for grid connection of multiple groups of single-phase inversion units applied to a microgrid system. The topological structure consists of at least oneDC / DC conversion unit, a shared direct current bus, a non-isolation inversion unit, a sensor unit, at least one isolation inversion unit and at least one control unit. In the actual use of the microgrid, the main power generation source is photovoltaic power or wind power and other new energies; due to actual mounting area and site limitation, the conventional inversion unit at the output power of 3-5KW only has a single-phase inversion apparatus while a three-phase four-wire system with the mains supply of 380V has relatively high three-phase imbalance characteristic; even if a three-phase inversion unit is used, it is hard to realize matching between each phase of power generation and a load and economic operation; in addition, multiple groups of single-phase inversion modules are connected to the power grid at the same time, and due to existence of the inversion bridge arm, interphase short circuit may be caused; and therefore, a novel apparatus capable of realizing mutual isolation of the single-phase inversion units and controlling the output power of each single-phase inversion unit to be matched with the load is needed, so as to realize the working pattern with the maximumenergy conservation and economic operation of the microgrid.
Description
technical field [0001] The invention relates to grid-connected power generation of a micro-grid system, and specifically relates to solving the three-phase mismatch problem in an actual micro-grid, improving the use efficiency of new energy generation such as photovoltaic or wind power, and preventing multiple sets of single-phase inverter units from being connected to a three-phase grid phase-to-phase short circuit problem. Background technique [0002] At present, in the application of the micro-grid integrated into the three-phase grid, the main source of power generation is new energy such as photovoltaic or wind power. Due to the limitation of the actual installation area and site, the traditional inverter unit with an output power of 3-5KW only has a single-phase inverter device , it is difficult to achieve the matching of the power of each phase. If the electric power of the new energy is less than the load power, it will be transmitted to the grid against the current...
Claims
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Login to View More IPC IPC(8): H02J3/38H02J3/26
CPCH02J3/26H02J3/383H02J3/386Y02E10/56Y02E10/76Y02E40/50
Inventor 牟英峰鲁成高万腾飞
Owner WUXI MEIKAI ENERGY TECH