| Variable refrigeration volume air conditioner (VRV) is widely used recently due to its merits such as effectiveness, comfortablity. In contrast to conventional inverter driven air conditioner, there are several indoor units with only one set of outdoor unit in VRV system, both proper mass flow distribution and compressor control are the two essential problems in developing the control system for VRV.In this thesis, the behavior of the VRV system is studied by the way of mathematical simulation. Based on the understanding of the characteristic of the system, control strategy and method for the system are then put forward. The main work is as followed:1. A two-evaporator VRV mathematical steady model is established as a representation of VRV system. This model is a powerful tool for the studying of VRV system.2. Based on the model, simulation is conducted to study the laws of the VRV system by varying its working parameter such as speed of compressor, openness of EEV, air volume of indoor units and indoor room temperature. Simulation results are also discussed and explained. And the conclusion drawn provides guidelines for the designing of control system for VRV.3. Existing control strategy is then studied and based on the characteristic of the indoor unit, control strategy is put forward. This control strategy can overcome interference between indoor units and have the attribute of expansibility, it aso guarantee the precise air temperature control in rooms and thus enhance the comfortablity.4. Control methods for EEV and compressor are studied and a fuzzy control system is developed for the control of air temperature by EEV. Also a new control method, here named as composite fuzzy control of insuction pressure is introduced for the control of compressor. This control method has an advantage over simple insuction pressure control method theoretically.
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