Control method of ship and shore power grid connection and seamless switching
A control method and seamless switching technology, applied in the direction of single grid parallel feeding arrangement, etc., can solve the problems of lack of frequency, phase and voltage control, etc., to reduce the probability of grid connection failure, enhance operability, and enhance system response the effect of time
Active Publication Date: 2019-07-26
JIANGSU UNIV OF SCI & TECH +1
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Problems solved by technology
[0005] The technical problem to be solved by the present invention is to provide a control method with frequency and phase pre-synchronization and the combination of electromagnetic torque and moment of inertia of virtual synchronous machine to control ship and shore power grid connection and seamless switching, which solves the problems in the prior art. Regarding the lack of frequency, phase and voltage control, it is a matter of actual control and not just a matter of studying the influence of parameters
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Embodiment
[0033] In this embodiment, the ship and shore power are connected to the grid and the control method for seamless switching is as follows: figure 2 As shown, the control method includes the following steps:
[0034] Step 1: Collect the expected voltage U of the ship power grid through the sampling device ref and power P ref , and at the same time collect the current i at the connection point between the land power grid and the ship power grid after passing through the transformer * and the output power P of the inverter * ;
[0035] Step 2: The expected power P of the ship grid ref and inverter output power P * Make a difference, judge the error, and control the output power P of the inverter through the compensation of the electromagnetic torque * , until the desired power P is reached ref ;
[0036] Step 3: Get the expected inverter power P ref and inverter output current i 1 * Through AC power calculation, the output voltage U of the inverter is obtained * ;
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The invention relates to a control method of ship and shore power grid connection and seamless switching. Power is directly compensated through electromagnetic torque Te to obtain an expected voltage;the frequency is further controlled through the relation between the rotational inertia J and the frequency response speed; and then a phase pre-synchronization process is added, so that grid connection and seamless switching are realized. The method has the advantages that the power and the voltage are detected through power and current detection devices, the three-phase voltage is obtained through a three-phase alternating current calculation law, and the shore power is used as an infinite power grid; power compensation can be carried out when the detected power does not meet the expected condition, the voltage obtained in the condition is compared with the expected voltage of the ship, the frequency and the phase position are obtained, and P-f control is carried out to adjust the frequency, the phase synchronization is adjusted under the condition that the frequency is equal, and the grid connection of the shore power of the ship can be stably realized; through the simulation of the characteristics of a virtual synchronous generator, the operability of shore power on the ship can be enhanced through the control of the ship PMS, and the probability of grid connection failure islowered.
Description
technical field [0001] The invention belongs to the technical field of ship shore power system, in particular to a control method for grid connection and seamless switching of ship and shore power. Background technique [0002] The international community has increasingly stringent standards for the control of ship pollutant emissions, and the use of shore power by ships berthing at ports has become one of the important measures to control ship emissions in ports. The marine shore power technology means that the ship stops using the auxiliary engine when it is berthed at the wharf, and uses the shore power supply instead to reduce the environmental pollution and noise pollution when the ship berths at the port. [0003] In order to connect the land power grid with the ship power grid, it is necessary to convert the land 50Hz power supply into the 60Hz or 50Hz power supply required by the ship through rectification, inverter, frequency conversion and voltage conversion. Many...
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Login to View More IPC IPC(8): H02J3/44
CPCH02J3/44
Inventor 苏贞张成高键杨奕飞吴百公许静何祖军
Owner JIANGSU UNIV OF SCI & TECH