What is the role of power inductance | GETWELL

The role of power inductance

(1) Flow resistance:

The self-induction electromotive force in the coil is always against the current change in the coil.It can be divided into high frequency choke coil and low frequency choke coil.

(2) Tuning and frequency selection:

The LC tuning circuit can be formed by the inductance coil in parallel with the capacitor.That is, if the natural oscillation frequency f0 of the circuit is equal to the frequency F of the non-AC signal, the inductive reactance and the capacitive reactance of the circuit are also equal, so the electromagnetic energy oscillates back and forth between inductance and capacitance, which is the resonance phenomenon of the LC circuit.At resonance, the inductive reactance and capacitive reactance of the circuit are equivalent and reverse, so the inductive reactance of the total circuit current is the minimum and the current flow is the maximum (refers to the AC signal of F = F0). Therefore, LC resonant circuit has the function of selecting frequency and can select the AC signal of a certain frequency F.

6 main performance parameters of power inductance

1. The main performance parameters of power inductance include inductance L, DC resistance DCR, DC overlapping current Isat, temperature-rise capacitive current Irms and self-harmonic frequency SRF.

2. Inductance is the nominal inductance value of inductance. Due to the existence of magnetic permeability and distributed capacitance, inductance will change with the change of frequency.The accuracy of inductance is generally M (±20%) or N (±30%).

3. Dc resistance DCR refers to the total DC resistance of enameled wires used between the electrodes of the product.

4. Dc overlapping current Isat refers to the inductance that will decrease in the case of continuous dc current. Generally, specifications are set according to the current value at the time of 30% decrease.

5.Irms refers to the inductance in the case of continuous dc current, the surface temperature of the inductor will rise, generally according to the rise of 40℃ current value to set the specifications.

6. Self-harmonic frequency SRF refers to the resonance of the inductance at a certain frequency due to the interaction between the inductance and the distributed capacitance of the inductance itself. The resonance frequency is the self-harmonic frequency of the inductance, and the power inductance is required to be used below the self-harmonic frequency.

Application of power inductors

Power inductors are widely used in the fields of communication, healthcare, industry, home appliances and automobile electronics, especially automobile infotainment equipment and power transmission/safety equipment in automobile electronics.In recent years, new energy vehicles have been continuously developed, including hybrid electric vehicles (HEV), extended hybrid electric vehicles (PHEV), pure electric vehicles (EV), and fuel cell vehicles (FCV), among which different voltage levels of power systems are required.

The DC/DC converter has become an indispensable key component in the design and development of new energy vehicles, while the power inductor is an indispensable component of the DC/DC converter, which can provide large current and high inductance and maintain continuous current by accumulating and releasing energy.