Filter design to avoid switching impact on gradient fields and maintain fidelity. Filters affect the driver bandwidth and reduce voltage availability for slew rate. Design issues and possible solution will be visited.

The gradient driver comprises the power supplies the amplifier stage with the filter and the digital control. Figure 3 shows a representation of the driver connected to the gradient coil in the scanner.

The digital control limitations and the design to overcome them and the tuning needed to achieve the desired performance. Detailed description of the control implementation and hardware options.

Correct thermal management implementation is needed to achieve consistent and reliable operation. The semiconductor and some other elements can be liquid cooled, some other parts are normally air cooled and will be a source of heating of the system equipment room.

The design should consider the tradeoffs between the performance and losses. Correct decisions are fundamental for a practical implementation of the gradient driver.

Analysis of power needs based on losses and amplitude requirements. This includes the characteristics of the semiconductors used for the driver.

The control loops are shown in Figure 5. The tuning of the feedback gain, the gradient coil model and the compensation are fundamental to achieve the accuracy and repeatability needed for the PSDs commanded to the gradient driver. We will cover some of the features that are needed for proper tuning of the control and impact on performance.

We expect to provide the audience with more understanding of the complexity of the driver and how can the requirements be achieved with existing and emerging new technologies for power electronics.

We will provide description design decisions explanation for a good understanding of the challenges faced for high performance gradient driver and the benefits obtained by the correct selection.

Control implementation and implemented functions needed for consistent best performance. The digital control provides a lot of possibilities for corrections to minimize the error at which the PSDs are produces by the driver.

Power supplies for the amplifier. The circuit topology requires a set of isolated power supplies that have to be sized to deliver the power losses of the gradient coil and the electronics.

The gradient system is normally the subsystem that requires the largest amount of power in the scanner. These requirements are an important part of the sizing and the cost of the system.

New power semiconductors like SiC may results in circuit simplification and lower power losses. We will talk briefly about the new devices available.

The circuit architecture and selection of semiconductors is of outmost imprtance to achieve the performance needed at the power level required.

The presentation will cover the details of all the elements and subsystems needed for the gradient driver. Also, a description of new technologies that make possible further improvements like new wide band semiconductors like SiC MOSFETs.

Figure 4 shows the key waveforms for each stage of the gradient driver: the power supply voltage delivered to the amplifier stage, the waveforms before the filter and the voltage applied to the gradient coil that will produce the gradient field.