In order to meet the needs of peak regulation and frequency regulation in power grid

the instruction of automatic generation control of thermal power units changes frequently

leading to an increase in fluctuation of fuel consumption of the units

which seriously affects the operation safety

economy and environmental protection of the units. According to the simplified nonlinear dynamic model

the feed-forward control logic of power load instruction to fuel consumption in the coordinated control system in the boiler-following-turbine mode was deduced. It is found that the basic structure of the model is the lead compensation link

and its large differential action causes the fluctuation of fuel consumption under variable load conditions. Therefore

the lead compensation logic of the nonlinear differential link was reconstructed. With the same differential control quantity

the instantaneous variation range of differential outputs was reduced and the adjustment time was shortened

thus to reduce the fluctuation in fuel consumption caused by the feed-forward differential action. The reconstructed nonlinear feed-forward control logic was applied to a 330 MW subcritical unit

the commissioning results show that the optimized control scheme can significantly reduce the fluctuation range of fuel consumption under variable load conditions on the premise of achieving the same control index.