| Within the rapid development of science and technology,it needs to pay more attention to the preservation environment of experimental supplies in laboratories.Especially,the experimental supplies used in biology,chemistry,medicine and other aspects in biochemical laboratories need to be properly preserved in an environment with extremely accurate temperature while the traditional laboratory thermostats can no longer meet the strict requirements nowadays.In this case,it is significant to develop a system with higher accuracy temperature control for laboratory thermostat.In this paper,a heating power supply is designed based on the precision characteristics of the laboratory thermostat temperature control system.The actual output voltage and output power of the heating power supply are 48 V and 1000 W respectively,the efficiency is greater than 90%,the power factor is higher than 0.98,while the output is strictly controlled within 20 m V,and the temperature control accuracy is 0.01°C.Firstly,this paper introduces three most common control technologies used for thermostat temperature control systems and recent research status and application examples from both international and domestic markets.Then two types of heating power supply are described.Through comparative analysis,this paper chooses the switching power supply as the heating power supply.The main body of this paper introduces the overall structure of the heating power supply of the thermostat firstly,lists the design requirements of the power supply system and briefly outlines the working principle of the power supply system.Then it introduces the selection of the topological selection of the active power factor correction circuit in the front stage of the heating power supply system.The power system chooses the Boost APFC circuit as the front stage circuit and selects NCP1654 as the control chip to control the front stage circuit.After comparing and analyzing several common DC/DC topologies,it can be concluded that the full-bridge LLC series resonant topology circuit is more suitable for the application scenarios of this paper,so this kind of topology circuit is chosen as the subsequent circuit of the incubator heating power supply system.Then,a simulation platform was built through MATLAB software,and the feasibility of the circuit design of the entire power supply system and the selection of components was proved through simulation experiments.In this paper,it chooses STM32 one-chip computer as the main controller of the whole system and uses its strong data processing ability to control the whole power system.Then,based on STM32,the software program design of the control part of the heating power supply system is completed,and the auxiliary circuits required by the entire system are designed.Finally,a corresponding experimental prototype was made and detailed tests were carried out.After analyzing the experimental results,it was proved that the design basically met the design requirements of the heating power system. |
