| Title |
EEV Superheat Control of a Multi-type Heat Pump by Using Dither Signal |
| Keywords |
Electronic expansion valve ; 전자팽창밸브 ; Hysteresis ; 이력 ; Superheat control ; 과열도 제어 ; Dither signal ; 디더신호 ; PI control algorithm ; 비례-적분 제어 알고리즘 ; Crossover frequency ; 교차주파수 |
| Abstract |
The electronic expansion valve(EEV) may be used to control the refrigerant flow rate for the multi-type heat pump. Stepping motor driven EEV may precisely control the refrigerant flow rate to meet each internal load requirement. To control the EEV, PI algorithm may be used. But the hysteresis of EEV deteriorates the performance of superheat control. To reduce the performance degradation, the PI algorithm along with the dither signal may be used. The dither signal, with about 10 times higher frequency than the system crossover frequency and about 10 times larger magnitude than the deadband of hysteresis, was selected for the superheat control of EEV. Experimental results showed the improvement of EEV control by adding the dither signal to the PI algorithm. |