Oven Control System Research Articles

How Does Ambient Temperature Fluctuation Influence the Short-Term Frequency Stability of OCXO?

Short-term frequency stability (STFS) is one of the most important specification of oven-controlled crystal oscillators (OCXOs). Although numerous studies have investigated factors that influence STFS, research on the impact of ambient temperature fluctuation is rare. This work investigates the relationship between the ambient temperature fluctuation and the STFS by introducing a model of the OCXO's short-term frequency-temperature characteristic (STFTC), which considers the transient thermal response of the quartz resonator, the thermal structure, and the oven control system. According to the model, an electrical-thermal co-simulation is adopted to determine the temperature rejection ratio of the oven control system and estimates the phase noise and Allan deviation (ADEV) that caused by fluctuations in ambient temperature. As a verification, a 10-MHz single-oven oscillator is designed. From the measured results, the estimated phase noise near the carrier agrees well with the measured results, and it can be seen that only when the temperature fluctuation is less than 10 mK at 1-100 s, the oscillator can maintain the characteristics of flicker frequency noise at the offset frequency from 10 mHz to 1 Hz, and the ADEV is possible to reach at the order of E -13 in 100 s. Thus, the model proposed in this study effectively predicts the impact of ambient temperature fluctuation on the STFS of an OCXO.

High Precision Hemispherical Resonator Gyroscopes With Oven Control Systems

This work presents a high reliable hemispherical resonator gyroscope (HRG) with a solution of an oven control system. The dynamics and thermal characteristics are firstly analyzed with a indication that the conventional look-up table (LUT) method can not fully compensate the HRG errors. The temperature cycling experiments show the hysteresis effect of the key parameters of HRG and fit the theoretical analysis. Then an advanced oven control approach is proposed to solve the challenges with optimized mechanical isolation, sensing and actuation electronics. The experimental verification results illustrate a comprehensive improvement for the HRG. Particularly, the bias instability (BI) is one order of magnitude better than uncompensated HRG that reaches a sub 0.001°/hr level. The daily bias and scale factor repeatability is 6× and 3× improved with a 1 week measurement, respectively. It also shows an excellent robustness to the environmental variation by doing a temperature cycling test. The bias level error of the uncompensated system is improved by 40×, and the scale factor stability can be also increased up to 19×. The BI and rate random walk (RRW) are all significantly enhanced to show a good environmental adaptability of the proposed ovenized HRG.

Implementation of a Temperature Control System in the Roasting Process of Cilembu Sweet Potatoes Using a Microcontroller Based Oven

Indonesia has a famous sweet potato called Ubi Cilembu that has a chewy and attractive meat structure. The advantages of this sweet potato, if baked in an oven, will produce a sweet honey flavor. Cilembu Sweet Potato that does not taste honey when eaten will reduce the delicacy because during the roasting process using an oven, there is no temperature control system that causes not toasted properly. Since reversing Cilembu yams is still done manually which can be endangering workers if exposed to a hot part of the oven. Because of this, the researcher will make it easier for users to work on the cilembu sweet potato roasting process more effectively than an oven control system is made. The implementation system is done by entering the temperature setpoint value and the timer via the remote displayed on the LCD, then the data is sent using a wireless module when the oven's half-timer time will rotate automatically by using the servo metal gear. The results are carried out by using a remote temperature control in the oven by entering the temperature setpoint value and the timer via the remote displayed on the LCD, then the data is sent using the wireless module when the furnace timer half time in the oven will rotate automatically using a metal servo gear. The system performance is designed to work within 2 hours with a weight of 1 kg of cilembu sweet potato using a temperature of 100.50 ° C.

A Micro Oven-Control System for Inertial Sensors

This paper presents a modular and generic micromachined oven-control system for use with miniature micro-electro-mechanical system (MEMS) transducers. The micro-oven-controlled off-the-shelf commercial six-axis MEMS inertial measurement unit (IMU), Invensense MPU-6050, provides the lowest reported temperature-induced root of sum of squares bias errors of 62.71°/h and 1.920 mg from -40°C to 85°C for three-axis gyroscopes and three-axis accelerometers, respectively. The micro-oven control system provides thermal isolation from the surrounding environment using a micro-machined isolation platform, vacuum-sealing, and a metal package. In addition, a CMOS temperature sensor, a proportional-integral-derivative-based temperature control scheme, and least mean square and random forest compensation algorithms are utilized to reduce temperature-induced bias drifts of IMUs. The most stable axes achieve peak-to-peak bias drifts of 12.78°/h and 665.2 ug during a thermal-cycle test for gyroscopes and accelerometers, respectively. The oven's heater power consumption is <;125mW at the lowest temperature, -40°C. This oven-control system can be applied to a wide range of MEMS sensors to reduce performance degradation due to temperature variation.

DC current measurement utilizing a resonant magnetically actuated piezoresistive microcantilever

This paper presents a novel current sensor by using a resonant piezoresistive microcantilever combined with magnetic actuation for the first time. An actuation power of several microwatts was necessary for stable self-oscillation. The sensor measured the DC current by obtaining the electrothermally induced resonant frequency shift of the microcantilever as a result of the Joule heating dissipated when the DC current flowed through the Wheatstone bridge on the microcantilever. Two theoretical models were established between the microcantilever's resonant frequency and the square of the DC current. The experimental results showed that the accuracy in the range of 0.5–5 mA (apart from 0.5 mA) using the two models was 2.60% and 1.00% with correlation coefficient value R > 0.999 in both cases, respectively. The current sensitivity of the sensor was about −3.983 Hz mA−2 in the range of 0.5–5 mA. To maintain stable results, the sensor chip should be sealed in vacuum and integrated into an oven-control system.

Coke Oven Intelligent Integrated Control System

In order to improve the level of management and control of coke oven, the research on intelligent integrated control system is carried out. In modern advanced control system of coke oven, the control scheme of feedback combined with feed-forward, and control merged with management are widely utilized. The integrated management and control system of coke oven is introduced systematically, including the system model, production plan and management, heating control system, the model and method of evaluating temperature, intelligent combustion control and the pressure control gas collector of coke oven. It is pointed out that the integration of management and control develops towards the orientation of coke oven control system. Considering the complexity and importance of flue temperature control in coke oven heating process, the control method of combining the stopping heating time control with the heating gas flow adjustment is proposed, hybrid intelligent control models of flue temperature are built.

Intelligent Control and Management Integrated System of Coke Oven

In order to improve the level of control and management of coke oven, the research on control and management integrated system is carried out. In modern advanced control system of coke oven, the control scheme of feedback combined with feed-forward, and control merged with management is widely used. The integrated control and management system of coke oven is introduced systematically, including the system model, production planning and management, heating control system, the model and method of evaluating temperature, intelligent combustion control and the pressure control gas collector of coke oven. It is pointed out that the integration of control and management is the developing orientation of coke oven control system.