We present a new digital phase lock technology to achieve the frequency control and transformation through high precision multi-cycle group synchronization between signals without the frequency transformation circuit....We present a new digital phase lock technology to achieve the frequency control and transformation through high precision multi-cycle group synchronization between signals without the frequency transformation circuit. In the case of digital sampling, the passing zero point of the phase of the controlled signal has the phase step characteristic, the phase step of the passing zero point is monotonic continuous with high resolution in the phase lock process, and using the border effect of digital fuzzy area, the gate can synchronize with the two signals, the quantization error is reduced. This technique is quite different from the existing methods of frequency transformation and frequency synthesis, the phase change characteristic between the periodic signals with different nominal is used. The phase change has the periodic phenomenon, and it has the high resolution step value. With the application of the physical law, the noise is reduced because of simplifying frequency transformation circuits, and the phase is locked with high precision. The regular phase change between frequency signals is only used for frequency measurement, and the change has evident randomness, but this randomness is greatly reduced in frequency control, and the certainty of the process result is clear. The experiment shows that the short term frequency stability can reach 10-12/s orders of magnitude.展开更多
电能计量表在使用过程中出现故障,会导致电力消耗情况记录精准度降低。为了避免该现象的发生,提出基于直接数字控制(direct digital control,DDC)的电能计量装置现场检验方法。依据电能计量装置相关特点,处理电能计量装置现场数据。结合...电能计量表在使用过程中出现故障,会导致电力消耗情况记录精准度降低。为了避免该现象的发生,提出基于直接数字控制(direct digital control,DDC)的电能计量装置现场检验方法。依据电能计量装置相关特点,处理电能计量装置现场数据。结合DDC技术,设计配变关口现场检验数据取证过程,通过前期准备、误差值确定和误差处理完成配变关口现场检验。设计互感器负荷现场检验数据取证过程,完成互感器负荷现场检验。在DDC支持下,设计信息隐藏模型。经实验验证:随着检验时间不断增加,无故障状态下所提方法检验精准度高于85%,在互感器故障情况下所提方法检验精准度最高为88%。展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 11173026the International GNSS Monitoring and Assessment System(iGMAS)of National Time Service Centre
文摘We present a new digital phase lock technology to achieve the frequency control and transformation through high precision multi-cycle group synchronization between signals without the frequency transformation circuit. In the case of digital sampling, the passing zero point of the phase of the controlled signal has the phase step characteristic, the phase step of the passing zero point is monotonic continuous with high resolution in the phase lock process, and using the border effect of digital fuzzy area, the gate can synchronize with the two signals, the quantization error is reduced. This technique is quite different from the existing methods of frequency transformation and frequency synthesis, the phase change characteristic between the periodic signals with different nominal is used. The phase change has the periodic phenomenon, and it has the high resolution step value. With the application of the physical law, the noise is reduced because of simplifying frequency transformation circuits, and the phase is locked with high precision. The regular phase change between frequency signals is only used for frequency measurement, and the change has evident randomness, but this randomness is greatly reduced in frequency control, and the certainty of the process result is clear. The experiment shows that the short term frequency stability can reach 10-12/s orders of magnitude.
文摘鉴于传统中央空调系统温湿度调节速率缓慢、偏差大、能耗高等缺点,提出了一种基于直接数字控制和Lon Works技术的智能建筑中央空调一次回风系统设计方案。系统底层控制网络采用海湾HW-BA5201 DDC控制器组建,上位机监控平台采用力控Force Control 7.0组态软件设计。通过温度和湿度传感器实时检测系统回风温度和湿度,PID自动调节给水阀和加湿阀开度,最终实现控制要求。系统设有压差保护,防冻保护,以及风阀执行器与风机联锁控制功能,具有一定的推广应用价值。
文摘电能计量表在使用过程中出现故障,会导致电力消耗情况记录精准度降低。为了避免该现象的发生,提出基于直接数字控制(direct digital control,DDC)的电能计量装置现场检验方法。依据电能计量装置相关特点,处理电能计量装置现场数据。结合DDC技术,设计配变关口现场检验数据取证过程,通过前期准备、误差值确定和误差处理完成配变关口现场检验。设计互感器负荷现场检验数据取证过程,完成互感器负荷现场检验。在DDC支持下,设计信息隐藏模型。经实验验证:随着检验时间不断增加,无故障状态下所提方法检验精准度高于85%,在互感器故障情况下所提方法检验精准度最高为88%。
