Model parameter identification of indoor temperature lag characteristic based on hysteresis relay feedback control in VAV systems

Li, Xiuming; Lin, Sida; Zhang, Jili; Zhao, Tianyi

doi:10.1016/j.jobe.2019.100839

Cited by 18 publications

(4 citation statements)

References 15 publications

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“…Equation ( 32) also indicates that the switching position is zero, that is, x 0 = 0, two periods T 1 and T 2 are equal theoretically. 30 Then, equation (26) becomes…”

Section: Analysis On Switching Positionmentioning

confidence: 99%

“…18 It has been applied in various control systems such as auto-tuning of process controllers, 19,20 current controllers, 21 servomechanism. 22 It is also useful in system identification 23,24 and parameter identification such as process model parameters in under-damped second order plus dead time processes, 25 indoor temperature lag in variable air volume systems 26 and backlash in two-mass systems. 27 We have applied it to mass measurement.…”

Section: Introductionmentioning

confidence: 99%

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Position-insensitive estimation of mass from limit cycle of velocity feedback relay system with Spring

Mizuno

Egawa

Takasaki

et al. 2021

Measurement and Control

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Mass measurement using relay feedback of velocity and restoring force compensation is investigated for determining the mass of an object under weightless conditions. In the measurement system, the velocity of the object is fed back through a relay with hysteresis and the force acting on the object is switched from a positive value to a negative value when the velocity reaches a positive threshold and vice versa. As a result, a limit cycle is induced in the measurement system and the mass is estimated based on the period of the limit cycle. In addition, restoring force compensation with a spring is introduced to avoid the drift of the trajectory. This compensation makes the static equilibrium state unique. However, the trajectory still drifts slightly. It causes some error in measurement when a simple formula of estimating mass is applied. To eliminate such an error, a new formula is derived to estimate the mass independently of the position of the trajectory that is determined by the switching positions in the relay actions. When the switching positions deflect from the origin at which the spring is in the natural length, the trajectory is not at the center and becomes asymmetric. It is analytically shown that the period of the limit cycle is minimum when the switching positions are at the origin. It indicates that mass is overestimated with the simple estimation formula when the trajectory is not at the center. The validity of the modified formula and the analytical results are confirmed experimentally.

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“…Equation ( 32) also indicates that the switching position is zero, that is, x 0 = 0, two periods T 1 and T 2 are equal theoretically. 30 Then, equation (26) becomes…”

Section: Analysis On Switching Positionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Position-insensitive estimation of mass from limit cycle of velocity feedback relay system with Spring

Mizuno

Egawa

Takasaki

et al. 2021

Measurement and Control

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show abstract

“…If the air flow measurement of the air flow sensor is lower than the actual air flow value, HVAC systems will consume more energy. If the air flow measurement of the air flow sensor is higher than the actual air flow value, it will not be able to meet the ventilation requirements of the building [ 20 , 21 , 22 ].…”

Section: Introductionmentioning

confidence: 99%

A Universal Calibration Device for an Air Flow Sensor of the VAV Terminal Unit

Zhang

Cai

Zhang

et al. 2022

Sensors

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In this paper, a new calibration device for an air flow sensor of the VAV terminal unit is designed. Multi-aperture air outlets are designed to meet the calibration requirements of the air flow sensor in a variety of measurement range. The device can calibrate the air flow sensors of different types of VAV terminal unit by a movable flow rectifier without repeating the design of a different calibration pipeline. The Raspberry PI is used to design the high-performance GUI interface and controlling algorithm to achieve a one-button intelligent calibration. The air flow sensors in three different types of VAV terminal units are used to calibrate the experiment. After testing, the differential pressure value measured by the air flow sensor can accurately measure the air flow within the accuracy of 5% after the formula conversion. The conversion from differential pressure values to air flow values requires precise calibration in order to establish an accurate air flow equation, and here the calibration device plays a key role. The negative effect caused by the distance between the flow rectifiers and the VAV terminal unit is discovered. In other words, the distance between the inlet flow rectifier and the air inlet of VAV terminal unit should be kept as close as possible, or within a range of 2~3 cm. Moreover, the distance between the air outlet of VAV terminal unit and the middle-flow rectifier should be kept as close as possible; otherwise, any slight gap will cause a huge error in the calibration result. The research contributes to the further study of airflow sensing technology through the conversion and calibration of differential pressure measurements to accurate air flow values.

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“…Many scholars have proposed VAV air-conditioning control methods. For example, hysteresis relay feedback control was introduced into the model parameter identification of indoor temperature hysteresis characteristics, thereby providing a new method for the identification of the characteristics of indoor temperature hysteresis in [1]. For indoor fresh air demand, the total fresh air flow is dynamically corrected on the basis of the detected occupancy rate of each area and relevant measurement values using fresh air from the overventilated area [2].…”

Section: Introductionmentioning

confidence: 99%

Fuzzy Sliding Mode Control of a VAV Air-Conditioning Terminal Temperature System

Niu

Yang

et al. 2020

Complexity

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A varied air volume (VAV) air-conditioning system comprises diverse input and/or output disturbances, which are commonly nonlinear, with large lag and uncertainty. Based on the traditional control methods, testing the controlling parameters of a VAV air-conditioning system is challenging. Sliding mode control could improve the robustness of the system due to the adaptive capacity of disturbance rejection. Moreover, the fuzzy algorithm could be employed to determine the stability of a sliding control system by adjusting the parameters in the approach rate, reducing the switching frequency, and weakening chatter. Fuzzy sliding mode control is investigated in this paper to improve the performance of a VAV air-conditioning system. Simulation results verify that the sliding mode control is suitable for a VAV air-conditioning system to achieve good adaptability and robustness considering the influence of multiple external variable disturbances. In addition, the chattering of the system is improved after the introduction of fuzzy control.

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Model parameter identification of indoor temperature lag characteristic based on hysteresis relay feedback control in VAV systems

Cited by 18 publications

References 15 publications

Position-insensitive estimation of mass from limit cycle of velocity feedback relay system with Spring

Position-insensitive estimation of mass from limit cycle of velocity feedback relay system with Spring

A Universal Calibration Device for an Air Flow Sensor of the VAV Terminal Unit

Fuzzy Sliding Mode Control of a VAV Air-Conditioning Terminal Temperature System

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