Adaptive Deadtime Compensation for Magnetic Resonance Imaging Driver

Magnetic Resonance Imaging(MRI) uses magnetic field gradients to do spatial encoding for imaging. To achieve the required performance, MRI gradient driver needs to provide current with extremely high fidelity to the commanded values of any arbitrary shape. Therefore, it requires very accurate compensations of nonlinearities. One of the major sources of the nonlinearity is the deadtime between the top switch and the bottom switch in each leg of the bridge to avoid shoot-through. This paper proposes an adaptive deadtime compensation method that can be built on top of the existing MRI driver without any additional hardware cost. It works well under different shapes of current command, reduces the error caused by the deadtime especially at low slew rate current command. Simulation and experimental results are provided to validate the proposed concept.