In our previous discussion, we Analysis the core saturation prevention design. Today, we will proceed with the Energy harvesting performance test.

4) .Energy harvesting performance test

When the current is in the range of 50~3000 A, CT can provide a secondary voltage of 7 V or more for the load, which meets the starting voltage of the subsequent circuit. Therefore, only one test is needed to evaluate the energy harvesting performance of the current in the range of 0~50 A.

Refer to Table 1 for magnetic core parameter settings, with a current range of 0-50 A, 100 turns of secondary winding, and a load resistance of 100 Ω. Change the current once and measure the voltage and power of the secondary load at this time. The simulation results are shown in Table 4, where P2 represents the load power.

After simulation testing, it can provide a voltage of 2.466 V and a power of 0.078 W for a 100 Ω load with a current of 5 A.

Because different design requirements have different selection criteria for parameters such as size and material, which can lead to different power, only common material model parameters and size were selected in the simulation. This time we provided more design methods, but the simulation results obtained are not the power limit values that can be achieved by this method.

5 Conclusion

We conducted research on the energy harvesting performance of CT based on open gap magnetic cores from a practical application perspective, established an energy harvesting model, and analyzed the influence of parameters such as turns and size on energy harvesting power. Based on the derived conclusions, we proposed a method to reduce the dead zone of CT power supply from the perspective of magnetic core parameters.

We propose an optimization method for magnetic core parameters to address the issue of low current energy harvesting. At a current of 5 A, the load voltage is 2.466 V and the output power is 78 mW. This method still provides limited electrical energy, but it is still a magnetic core parameter design method. Based on this, combined with other methods such as parallel matching capacitors and designing charge pump circuits, the energy harvesting range of CT can be further increased, and further research will be conducted in this direction.

In response to the problem of high current energy harvesting, unlike general methods, this method does not interrupt CT energy harvesting. From the perspective of the working point of the magnetic core, a method combining multiple turns and parallel resistance is proposed. When the parallel resistance is selected as 15 Ω, the magnetic core always operates in the unsaturated region within the range of 0-3 kA of primary current.

The CT optimization design method proposed this time takes into account both the upper and lower limits of the energy extraction range, increases the working range of the magnetic core, ensures the normal operation of the CT, and to some extent solves the installation and design complexity problems.

Original file:https://mp.weixin.qq.com/s/modmnFdmG_bJNvRLRuoPew