Research On Control Strategy And Optimal Scheduling Of CCHP System

In today’s society, with the energy shortage and environmental pollution problems become increasingly serious, the distributed power system with energy saving and environmental protection advantages has been widely research and application. The CCHP systems based on the principle of waste heat recovery and energy cascade utilization, the energy efficiency is greatly improved. This kind of system has become the main developing direction of distributed power. The highly efficient system which contains a variety of renewable energy,and combined with power and heat storages, has important research and practical value.This paper is based on the "863" project"New efficient biomass gas engine-generator sets research and CCHP demonstration application". The multiple micro-power CCHP system is designed firstly, and then mainly studies the control strategy of the micro source, the optimal operation of economy and environmental protection for the overall system. The main work is as follows:Through the analysis of the energy demand for demonstration user, a new system scheme based on 30kW gas internal combustion generating set as the core unit was designed. In order to solve the system configuration redundancy problem of the single energy scheme, the photovoltaic power generation and solar collector unit were added. Meantime, adding the power storage and thermal storage unit to solve the electric-heat coupling problem of the gas internal combustion generating set, it can also enhance the system’s load adjustment ability. This system can be applied to a variety of operating conditions, at the same time can improve the system reliability and economy.The MPPT control method and iterative feedback control method were designed to guarantee the maximum power output of photovoltaic generation and solar collector systems. To ensure the power quality and stability of off-grid system, the voltage and frequency control method which based on the speed and voltage of the gas internal combustion generating set was designed, it has perfect effect.It is established the corresponding mathematical model of optimal operation, which is aimed at the main energy supply and energy storage unit of CCHP system. After considering the economic and environmental protection about CCHP system, a multi-objective function including the operation maintenance cost and environmental benefits was established. To ensure the result of optimal operation is reasonable, it sets a limit on the power generation capacity limits, the energy storage unit capacity, and electric power balance constraints.For the above objective function and the actual user load data. Considering the different electricity price policy, new energy policy and off-grid operation condition, using genetic algorithms to get the optimization results of the system unit under five cases. According to data analysis, the lowest operation maintenance cost and the total cost occurs under the conditions of time-dependent electricity price and the allowed to sell electricity. Compared with the traditional system, this CCHP system has obvious economical and environmental protection advantages in all of the five conditions above.