The invention discloses an
electromagnetic flowmeter excitation
control system based on differential compensation PFM modulation. The
electromagnetic flowmeter excitation
control system is composed ofa direct-current power supply, a PFM controller, a filter circuit, a
ripple compensation circuit, a differential compensation circuit, an amplitude limiting feedback circuit, an excitation sequentialcircuit, an
excitation coil drive circuit and a current sampling circuit.
Constant current control is realized by adopting a PFM modulation technology,
system efficiency is improved, and
system powerconsumption and a
system temperature rise are reduced.
Excitation current overshoot is suppressed by using the differential compensation circuit so that
excitation current overshoot and dynamic adjustment time can be reduced and an excitation frequency can be enhanced. The
ripple compensation circuit is used for reducing exciting current ripples and improving exciting current precision. The excitation sequential circuit generates two paths of complementary rectangular wave excitation signals with dead zones and controls an
excitation coil driving circuit, an output end of the excitation coildriving circuit is connected with an
excitation coil, and
excitation current reversing is achieved. According to the excitation
control system, the excitation frequency can be improved, the
power consumption and the temperature rise of the excitation system are reduced, and the
excitation current ripples are reduced.