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Unbalance load of virtual synchronous generator belt and control method of parallel connection of virtual synchronous generators

A technology of balanced load and virtual synchronization, applied in the direction of electrical components, circuit devices, AC network circuits, etc., can solve the problems of unbalanced output voltage and circulating current in unbalanced loads, and achieve the effect of eliminating circulating current

Inactive Publication Date: 2018-12-07
XIAN UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] The purpose of the present invention is to provide a virtual synchronous generator with unbalanced load and its parallel control method, which solves the problems in the prior art that the unbalanced load causes the output voltage to be unbalanced and the multi-VSG with unbalanced load has circulating currents

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  • Unbalance load of virtual synchronous generator belt and control method of parallel connection of virtual synchronous generators
  • Unbalance load of virtual synchronous generator belt and control method of parallel connection of virtual synchronous generators
  • Unbalance load of virtual synchronous generator belt and control method of parallel connection of virtual synchronous generators

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Embodiment

[0090] The present invention is a virtual synchronous generator with unbalanced load and its parallel control method, which is specifically implemented according to the following steps:

[0091] Step 1. Calculate the VSG output voltage U in the two-phase stationary coordinate system α , U β , output current I α , I β , calculate the angular frequency ω and the VSG output voltage reference value U from the active power P ref , specifically follow the steps below:

[0092] Step 1.1. Set the DC bus voltage U of VSG dc is 700V, filter resistor R f , inductance L f , capacitance C fThey are: 0.01Ω, 2mH, 20μF, the two phases of the AC output terminals A and C are connected across a 10Ω resistor to run, forming a single VSG with an unbalanced load, and collecting the VSG output three-phase voltage U a , U b , U c , three-phase current I a , I b , I c ;

[0093] Step 1.2, calculate the voltage U in the two-phase stationary coordinate system through the three-phase voltag...

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Abstract

The invention discloses an unbalance load of a virtual synchronous generator belt and a control method of parallel connection of the virtual synchronous generator belts. The control method comprises steps of firstly, calculating VSG output voltage Ualpha, Ubeta, and output current Ialpha, Ibeta, under a two-phase static coordinate system, and calculating the angular frequency omega and a VSG output end voltage reference value Uref through active power P; calculating reference values Ealpha and Ebeta of the VSG output voltage under the two-phase static coordinate system; using a positive sequence compound proportion integral controller as a voltage and current loop-locked controller to control the voltage Ualpha, the voltage Ubeta, the current Ialpha, and the current Ibeta under the two-phase static coordinate system so as to obtain a PWM modulation signal; obtaining angular frequencies omega 1, omega 2 of two VSGs; and by use of the integral controller, allowing the omega 2 to follow the omega 1, using the output as compensation quantity and adding the compensation quantity into a rotor motion equation, thereby achieving parallel connection of two VSGs. According to the invention,problems of unbalance of output voltage caused by unbalance load and circulation in the unbalance load of multiple VSG belts in the prior art are solved.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and in particular relates to a control method for a virtual synchronous generator with unbalanced load and its parallel connection. Background technique [0002] For the problem of unbalanced load, the existing methods mainly include two aspects: circuit and control strategy. In terms of topology, there are: three-phase combined converter, but it uses more devices, is large in size, and the loss is relatively increased; the traditional three-phase three-leg converter is connected to the load through the output transformer (Y / △) , but increases the volume of the system, and the cost is relatively high; three-phase split capacitive topology, but the problem of voltage equalization and the capacity of split capacitors must be considered; three-phase four-arm topology, but the number of devices used increases, which increases losses. In terms of control strategies, most of the existing con...

Claims

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Application Information

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IPC IPC(8): H02J3/38
CPCH02J3/381
Inventor 张辉张倩李晓强支娜梁誉馨
Owner XIAN UNIV OF TECH
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