Transistors｜Evaluation

The Importance of the Reverse Recovery Characteristics of Switching Elements in Inverter Circuits The Importance of the Reverse Recovery Characteristics of Switching Elements in Inverter Circuits　－Summary－

2023.12.27

The Importance of the Reverse Recovery Characteristics of Switching Elements in Inverter Circuits　－Summary－

Because there are many occurrences of MOSFET switching in a 3-phase modulation inverter circuit, efficiency worsens under light loading, when switching losses are dominant. The effect of reverse recovery losses at MOSFET turn-on are particularly large, and reducing these losses is highly important.

From the results of double pulse tests of PrestoMOS™ devices, we have confirmed the effect of reducing turn-on losses under both light loading (2 A) and heavy loading (10 A). Thus it can be said that PrestoMOS™ MOSFETs are effective for boosting the efficiency of inverter circuits.

Below, the key points set forth in the articles up till now are summarized, together with links to the articles.

▶The Importance of the Reverse Recovery Characteristics of Switching Elements in Inverter Circuits　－Introduction－

Key Points of This Article

・An inverter circuit is a type of power conversion circuit that converts a direct current (DC) into an alternating current (AC).

・Inverter circuits are often used in motor driving applications.

・In inverter circuit operation, the reverse recovery characteristics of internal diodes greatly affects losses.

▶Types of Inverter Circuits and Energization Methods

Key Points of This Article

・Inverter circuits can be classified into two main types, single-phase inverter circuits and 3-phase inverter circuits.

・For motor driving, 3-phase inverters are used because of the stable torque obtained and the ability to suppress vibrations and noise.

・Energization methods that can be used when driving a motor with a 3-phase inverter include square-wave driving (120° commutation), sinusoidal driving (3-phase modulation, 2-phase modulation), and others, each with its own advantages and drawbacks.

・Here sinusoidal driving (3-phase modulation), which is often used for motor driving, is taken as an example.

▶Basic Operation of 3-Phase Modulation Inverter Circuits

Key Points of This Article

・During operation of an inverter circuit, reverse recovery currents occur in body diodes.

・If reverse recovery times are long and reverse recovery currents are large, increased losses result; this is one disadvantage of inverter circuits.

・By using MOSFETs with short reverse recovery times and small reverse recovery current peaks, losses in inverter circuits can be reduced, and the risk of MOSFET destruction can be alleviated.

▶Comparison of Losses in a PrestoMOS™ MOSFET and a Standard SJ MOSFET Using Double-Pulse Tests (Actual Measurement Results)

Key Points of This Article

・In order to evaluate reverse recovery losses in an inverter circuit, double pulse tests were used.

・In comparisons of PrestoMOS™ MOSFETs with standard SJ MOSFETs, it was confirmed that PrestoMOS™ MOSFETs, with superior reverse recovery characteristics, had smaller switching losses.

・This indicates the superiority of PrestoMOS™ MOSFETs with respect to reducing losses in inverter circuits.

▶Comparison of Efficiency of a PrestoMOS™ MOSFET and a Standard SJ MOSFET in a 3-Phase Modulation Inverter Circuit (Simulations)

Key Points of This Article

・Simulations were used to determine the circuit efficiency of a 3-phase modulation inverter circuit and the losses per MOSFET.

・Upon comparing PrestoMOS™ MOSFETs and standard SJ MOSFETs in a 3-phase modulation inverter circuit, the circuit using the PrestoMOS™ MOSFETs, with superior reverse recovery characteristics, was found to have higher efficiency (lower losses).

・In a 3-phase modulation inverter circuit, PrestoMOS™ MOSFETs with their superior reverse recovery characteristics are clearly advantageous in terms of efficiency.

Reference document: “Double-pulse test substantiated advantages of PrestoMOS™“, Application Note (No. 60AN116J), ROHM Co., Ltd.

    Transistors

    Basic

    Evaluation

    THIS WEBSITE USES COOKIES.
    By continuing to browse this website without changing your web-browser cookie settings, you are agreeing to our use of cookies.
    Privacy Policy
    OK