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| The AutoCommutation technology allows to build small and efficient DCDC converters with highest efficiency and low electromagnetic interference (EMI). |
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| Features |
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- allows higher switching frequencies because of minimized switching losses
- substantially lower EMI due to limited current slope during switching off
- low EMI provides for an economical filter design
- compact and lightweight construction due to low losses, small main inductor and small EMI filters
- very high efficiency in excess of 99% achievable
- favourable control characteristics because only a small amount of energy is stored in the main inductor
- energy can be converted in both directions ( bi-directional )
- longer service life due to smaller component stress
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| Description |
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In semiconductor power stages, power dissipation is mainly determined by conducting-state losses and switching losses. With increasing frequency, switching losses become dominant because switching is done much more frequently. In order to build small yet powerful converters, high switching frequencies are a prerequisite.
Employing the AutoCommutation technology optimized by BRUSA, switching losses are reduced substantially, because the current can flow through the freewheeling diode until it decays by itself. Just then the power switch takes over the current; because it is zero in that moment, practically no switching losses occur.
Besides the favourable properties concerning losses, the switching process is much smoother and therefore produces far less interfering radiation. Therefore a minimum of measures for EMI suppression is sufficient. Minimal EMI filters and the low specific losses allow for a very high power density.
In order to keep the system immanent current ripple small, two of those power stages are operated in parallel with inverted phase. This way the current ripple can be reduced close to zero under optimum conditions. The technology further allows to let the current flow in both directions (bidirectional operation) without additional measures. This is especially useful for DCDC converters that are operated in fuel cell or hybrid vehicles, because high voltage can be generated from the 12V battery to start up and later the same device can recharge the battery. |
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