The invention relates to a
thermodynamic system of an extraction
back pressure turbine and a control method of the
thermodynamic system. According to the
system, an ultrahigh pressure cylinder and an
intermediate pressure cylinder are separately connected to a
regenerative system; a
high pressure cylinder is connected to a condensing
turbine; and the
turbine is connected to an auxiliary
power grid through a generator motor and a converter. The control method comprises the steps that: a boiler is started, and the generator motor serves as a motor to drive the turbine and a
feed pump shaft
system to operate; after the turbine enters an impulse rotating mode, a turbine control valve is controlled to be enlarged, the turbine drags a
feed pump to operate, and the generator motor operates as a generator; after the turbine rotates, the turbine and the
feed pump enter a normal
operation mode, the converter is adjusted to control and balance output of the turbine and the feed pump, and then the rotation speed of the feed pump is controlled; and when the converter and the
motor generator break down, the turbine control valve is controlled to be turned down to prevent the turbine from overspeed. Compared with the prior art, the
thermodynamic system has the advantages that the problem of a large
heat transfer temperature difference can be solved, meanwhile, reliable operation of the
system can be guaranteed, and the heat efficiency of the system is improved.