Of Co <sub>, 2 </ Sub> Electronic Control System Of The Refrigerant Heat Pump Water Heater Tank Study

As an increasing need for protecting the environment, a new type of the heat pump water heater with the natural refrigerant CO₂ will appear in water heater market. This type of water heater is high in efficiency, low in energy, rapid in operation, reasonable in safety and protecting-environment. Researches on the heat pump water heater are carrying out in many famous high schools and well-known corporations.Firstly, the paper provides an overview of the latest researches on heat pump water heater with refrigerant CO₂ home and aboard. At present, high efficiency and low cost are the main tasks for this kind of heater. Electrical control system is researched in order to increase the efficiency. Considering the difficulties in debugging and time, this paper focuses on the electrical controller of water tank.Secondly, this paper presents the composing and principle of heat pump water heater with refrigerant CO₂, and according to the principle, the controller system of water tank is designed. The digital signal controller dsPIC30f6010 is the main controller chip, the chip IRAMS10UP60B produced by IR company is the drive chip of brushless DC motors, and a3968slb is the drive controller chip of the electric mixed-water valve. As the chips used in this system, the circuit is compact in construction, small in volume, good at anti-interference. Discussions on drive circuits of motor are also mentioned, and a series of measures are taken in optimizing the circuit in order to support the application in the industry.Thirdly, the paper researches on the control strategy of water tank system, which involves the PWM modulation of brushless DC motor, the control of electric mixed-water valve which change the proportion of cold water and hot water, three line communications, CAN communications and UART communications. The signal polar driving method for brushless DC motor is emphasized. This proposed method could make the maneuverability and response of the electric controller of water tank better. Through analysing the construction and functions of the electrical mixed-water valve, the novel control strategy for electrical mixed-water valve is proposed.At last, undee analyse and experiment on the electrical controller of water tank prove the reasonability in design and liability in performance, while the good following performance of the motor is known according to the simulation for the rotated speed of brushless DC motor.