Magnetic actuation techniques and microrobots have attracted great interest since they have potential in biomedicine applications. Interventional techniques have emerged as a tool to handle a wide range of minimally invasive surgeries (MIS). However, current MIS procedures are constrained by the limitation of manual operation by surgeon. Thus, various microrobotic solutions including magnetic navigation systems have been proposed for MIS, which carries many potential benefits such as reduced incision, less intraoperative hemorrhaging and postoperative pain, and faster recovery time. In recent decades, many electromagnetic actuation (EMA) systems have been reported and involved to general surgery. The EMA system allows to generate efficiently magnetic source for microrobot control when its specifications are further investigated and satisfied for the desired application. To precisely manipulate the biomedical microrobot, a key issue still relies on the design of a suitable EMA platform. In this paper, we demonstrate a mathematical approach for the design configuration of magnetic system with multiple electromagnets. Especially, the required magnetic coil number has been investigated where the heading motion control, magnetic force control and their combination control are discussed respectively. The singular cases of control are pre-evaluated by a mathematical analysis of the simulated electromagnetic field. In addition, the placed positions and tilted orientations of the applied electromagnets are investigated for the optimization regarding the six typical configurations of EMA platform with 4, 6 and 8 coils. The various configurations of EMA systems have been comprehensively analyzed. Therefore, with the number of electromagnets and their optimal configuration obtained by the proposed approach, the EMA system can be initially established.