CONTROL SYSTEM FOR NON-RESONANT MICROWAVE DRYERS

摘要

The control system monitors the input power to and the output from the dryer applicator, and varies the input power to the applicator as a function of change in applicator efficiency and input power. The control system may consist of a first and a second circuit. The first circuit receives a signal Pin+291 from a first monitor and a signal Pout+291 from a second monitor. These signals are combined into an efficiency signal eta 1 to which a reference efficiency signal - eta o is added. An amplifier having a predetermined gain K amplifies the resulting signal to produce -K( eta 1- eta o). The second circuit adds the signals Pin1 from the first monitor, -K( eta 1- eta o) from the first circuit and Pin+352 , a signal representative of input power for a reference condition, to produce an output signal Iin+291 - [Pin+352 + K( eta 1- eta o)] which is coupled to the microwave source to control the input power to the applicator. The reference signal Pin+352 may be generated by a voltage source as a function of transport speed of the load through the applicator.