Capacity estimation method for energy storage device of common direct-current bus alternating-current transmission system

Abstract

The invention relates to a capacity estimation method for an energy storage device of a common direct-current bus alternating-current transmission system, which comprises the steps that a common DC bus multi-motor model is constructed, and the real object in the common DC bus multi-motor model comprises a DC bus and a motor; an energy storage device is arranged in the model, the capacity of the energy storage device is estimated according to the set model, and the method specifically comprises: establishing a first state sub-model of direct current bus operation; establishing a second state submodel of motor operation, wherein the first state sub-model and the second state sub-model correspond to each other; calculating the state quantity of the motor under the model; combining the first state sub-model and the second state sub-model to form a common DC bus multi-motor model for the common DC bus and the motor at the same time; and calculating the estimated capacity of the energy storage device according to the dynamic change of the common DC bus multi-motor model. The energy storage device is adopted, the energy storage device is estimated, impact on a power grid is avoided, and the electric energy quality is improved.

Description

technical field [0001] The invention relates to the technical field of AC transmission systems, in particular to a method for estimating the capacity of an energy storage device in a common DC bus AC transmission system. Background technique [0002] As the degree of industrialization continues to increase, the number of systems that companies use to work with multiple motors also increases. The status of energy in industrial systems is particularly important. Energy conservation and emission reduction have become a public awareness among the general public, and motors can be It is an energy-consuming device, and it can also be an energy-feeding device. Due to the needs of industrial production and product manufacturing, the operating states of motors in different motor systems are different. Sometimes the motor equipment will decelerate, accelerate or brake rapidly, such as the dozing machine in oil field equipment, and the motor in large mold factories. Lathe equipment, a...

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Problems solved by technology

[0003] At present, in order to fully recover and utilize the regenerative energy generated by the braking of motor equipment, it is proposed to connect multiple motors to the same DC bus, so that the regenerative electric energy generated by the motor in the braking state can be easily and quickly absorbed by the motor in the electric energy state. Utilization can not only consume the regenerative electric energy, but also achieve the effect of energy saving and emission reduction. Complete absorption, which will definitely lead to an increase in the voltage of the DC bus, and the voltage is too high, which will reduce the service life of the equipment, or directly damage it, seriously threatening the safety of production; the conventional method to solve this problem is to connect energy-consuming Resistor or feedback device, through its consumption or feedback of regenerative electric energy that cannot be fully absorbed by the motor in the energy consumption state, reduces the voltage of the DC bus to make the equipment work within the rated voltage range

However, the method of resisting energy consumption has a poor energy-saving effect; the method of feeding back to the grid has complicated control and high cost, and is only suitable for stable grid voltages that are not prone to failure, such as grid voltage fluctuations are not greater than 10%; therefore, In view of the deficiencies of the above-mentioned energy-consuming devices and energy-feeding devices, in order to reduce the energy loss in the AC drive system, this application directly adopts the busbar of the energy storage AC device, which avoids the impact on the power grid, improves the power quality, and designs a Estimation method for energy storage device capacity of common DC bus AC drive system

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