The Research Of Medical Thermostat Heating Power Supply Based On LLC Series Resonance

The high accuracy temperature control system is the most critical part of the medical thermostat.The high precision temperature control system is an important guarantee for the normal work of the thermostat because of the particularity of the environment for the use of the thermostat.This paper designs a set of heating power for the temperature control system of medical thermostat.The output voltage is 48 V,the output power is 2000 W,and the output voltage ripple is less than 20 mV.This paper describes the research status and main characteristics of medical thermostat at home and abroad,and expounds the importance of high precision temperature control system to constant temperature tank.The superiority and necessity of selecting switch power instead of linear power as heating power source of temperature control system is demonstrated.The main body of the text first introduces the overall structure of the heating power supply of the medical constant temperature trough,then introduces the topology selection of the power factor correction circuit of the heating power supply,chooses the Boost APFC circuit as the front stage circuit,and the control part adopts the PFC circuit control chip UC3854 of the UC company.Then,considering the power density,electromagnetic compatibility and overall efficiency,the LLC full bridge resonant converter is selected as the DC/DC converter of heating power supply.The equivalent circuit model is established by FHA,and the main characteristics of the LLC full bridge resonant converter are analyzed by Matlab software.The working area is divided by the switch tube to realize the ZCS as the condition of realizing the ZVS and the voltage regulator.The LLC full bridge resonant converter is simulated by PSIM software.The correctness of the principle analysis is verified,and the optimal circuit parameters are obtained.Then,the MCSS12xS128 microcontroller MCSS12xS128 is selected as the control chip of the resonant converter,and the hardware design and selection of the control system,the software program design of the control system and the anti-interference analysis of the control system are carried out.Finally,an experimental prototype is made and verified.The experimental results basically meet the requirements of the design.