Furnace hearth negative pressure control system with inconsistent variable rotational speed driving property of induced draft fan

The utility model relates to a furnace hearth negative pressure control system with an inconsistent variable rotational speed driving property of an induced draft fan, which consists of a furnace hearth negative pressure signal input module, a variable frequency control regulator module, a baffle plate control regulator module, a first adder module, a furnace hearth negative pressure measured value-set value deviation control baffle plate opening degree module, a change-over switch module, a second adder module, a variable frequency and baffle plate automatic switching control module unit in full automatic way, a first control frequency converter imbalance control module, a second control frequency converter imbalance control module, a baffle plate A/M (automatic/manual) module of a control induced draft fan A, a baffle plate A/M module of a control induced draft fan B, a rotational speed A/M module of the control induced draft fan A and a rotational speed A/M module of the control induced draft fan B. The system is mainly used for solving the problem that two induced draft fans A/B of the existing boiler respectively adopt rotational speed control and baffle plate control, so that the economy can not be maximized; and the system can realize the automatic switching between the variable rotational speed and the baffle plate under the full automatic way.