Magnetic field-based current sensors have been widely employed in power electronics and power systems due to their non-invasive measurement capability, high bandwidth, and high precision. Typical examples include sensors based on the Hall effect, tunneling magnetoresistance (TMR), and diamond quantum effects. However, these sensors are prone to transient voltage interference, which induces switching spikes at their output terminals. This study investigates the generation mechanism of transient voltage interference through comprehensive circuit analysis and establishes an equivalent circuit model to characterize noise transmission pathways. To address this issue, a novel comb-shaped shielding structure is proposed to suppress transient voltage coupling. The equivalent circuit model incorporating the comb-shaped shielding configuration is developed to analyze its noise attenuation performance. The equivalent circuit model of the current sensor with comb-shaped shielding is constructed. Experimental results demonstrate that the proposed shielding architecture achieves over 95% interference attenuation, effectively eliminating switching spikes while preserving the sensor's intrinsic characteristics.

This paper employs an active clamping module (ACM) to balance voltages of series-connected IGBTs in a medium voltage (MV) voltage source converter (VSC), which has been used for SiC MOSFETs. The principles of charging and discharging within the ACM are briefly introduced, revealing that the ACM capacitors have less charging current compared with series-connected SiC MOSFETs due to tail current. This process is modeled, leading to guidelines for selecting appropriate ACM capacitance. Design considerations for a MV VSC are discussed. Preliminary back-to-back tests on IGBT half-bridge modules were conducted at a DC voltage level of 400V and an AC current of 150A, confirming the effectiveness of the proposed analysis and design.

Silicon carbide (SiC) MOSFET module in HybridPACK™ drive package has been employed for mainstream automotive high power inverter applications. The short-circuit fault, however, threatens the reliability of the power module to a large extent. The tunnel magnetoresistance (TMR) sensor indicates short response delay, fair accuracy and low temperature drift for the short-circuit protection. The TMR sensor detect the short-circuit current by sensing the magnetic field in the sensitive direction. For the purpose of compact application and convenient current control, the TMR sensor is integrated on the surface of the power terminal. Concrete magnetic analysis with the assistance of finite element method (FEM) calculation is conducted by which means the short-circuit fault is to be detected in advance. A prototype based on SiC MOSFET module (STARPOWER MD29HTC120P6HE, 1200V/450A) is constructed to testify the TMR-based scheme. The short-circuit detection time of the TMR sensor is within 100ns and the SiC MOSFET module is protected in a safe manner.

A three-phase 3.3kV/400kVA voltage source converter (VSC) based on series-connected power devices for medium voltage variable speed drives is designed in this paper. The series-connected power devices are balanced using an active clamping circuit, which consists of an auxiliary switch and a capacitor. During the switching period, the power device voltage will be clamped at the voltage of ACM capacitor. By balancing the voltages of ACM capacitors, we can balance the voltages of series-connected power devices as well. The balancing circuit does not affect the switching of main power devices, and the power devices in the prototype switch at 10kHz. The power loss of the balancing circuit is minor. In each arm of the prototype, double-sided cooling modules as well as heatsinks are stacked vertically to series connect 6 power devices. Experimental tests on the prototype have been tested under 1kV with 4 power devices connected in each arm, and the voltage imbalance degree of the 4 series-connected power devices is less than 5%. Thermal simulation results show the junction temperature is 79°C under the rated power 400kVA. The power density of the prototype is 4.3MVA/m 3 .

In power converters, current sensing is essential for control and protection. This paper employs tunnel magnetoresistance (TMR) to non-invasively measure the PCB trace current in high frequency power converters. The operating principle of the TMR sensor is briefly introduced. Then we discuss the influence of skin effect on TMR measurement delay and bandwidth. Based on the finite element method (FEM) simulations, optimal install locations of the TMR sensor are found to avoid the influence of skin effect. An empirical formula is provided to summarize the optimal install locations under different trace widths. By putting the TMR sensor at the optimal location, the measurement delay is reduced from 517ns to 102ns according to experimental results. Next, a comb-shaped shield is proposed to suppress the switching spikes of TMR sensor output caused by common mode noise. The parameters of the comb-shield are chosen such that the electric field are shielded without affecting the magnetic field distribution. With the proposed comb-shaped shield, the TMR output spikes is reduced from 0.20V to 0.05V, whereas the measurement delay is almost not affected (W/O-102ns, with114ns).

Within a power electronics transformer (PET), the medium frequency transformer (MFT) is one of the key components for the whole system providing the required isolation and the voltage conversion between primary and secondary sides. A comprehensive design procedure is presented aiming to achieve high-voltage-insulation and high-efficiency. Referring to insulation standard, transformer insulation parameters are determined. To achieve the high efficiency, the number of turns is discussed considering both the calculated core loss and the estimated winding loss. A 30kVA transformer prototype is constructed and extensive measurements are performed including insulation tests, transformer loss and parasitic capacitance. The transformer prototype passes the IEEE Std. C57.12.01 standard in terms of insulation and performs well in a resonant DC-DC converter. The measured winding and core losses under rated voltage and current are 117.9W and 72.4W respectively.

In this paper, a resonant dc-dc converter with modular rectifier is proposed for high voltage gain and wide output voltage range applications such as interconnecting renewables to the medium voltage dc grid. The modular rectifier on the secondary side is used to support the high voltage and the number of submodules (SMs) can be chosen depending on the output voltage. Wide range of voltage regulation is achieved by regulating the frequency and the duty cycle of the SM gate signals. The proposed converter can achieve ZVS for the primary side switches and ZCS for the secondary rectifier. An 800W prototype with one SM in each arm is constructed to demonstrate the operating principle of the proposed converter. The efficiency under voltage gain 1, 1.25 and 1.5 are measured and the peak efficiency is 96.8%.