cupoftea
Advanced Member level 6
Hi,
Supposing you had a 24V, 100A isolated PSU. 3-phase input via 3 phase rectifier. (No neutral to rectifier). Post rectifier capacitance of 24uF (MAB MKP). Being switched by a fairly simple looking high frequency converter, with 4 primary side switching (1200V) IGBT’s (IXER35N120D1). Some kind of transformer of size approx. 12cmx7cmx6cm (can’t see it, its in plastic enclosure). The transformer is off the IGBT PCB, and is wired to it. The transformer’s isolated output goes a to bus bar pair on its way to the output capacitor bank (approx 20 x 35V 1200uF El caps) . As the bus bar pair makes it way to the output capacitor bank from the transformer, (quite a way, about 20cm) one of the bus bars has seven CS467090 sendust rings round it.
The other bus bar goes through a LEM LA306-S Current monitor.
CS467090 sendust rings
https://www.alibaba.com/product-det...-Transformers-CS467090-77442_62351494118.html
CS467090 sendust rings are Fe-Si-Al material. This surely does not have the high frequency properties necessary for use in this place? Wouldn’t you want NiZn rings? Why are the Sendust ones used?
I am guessing the switching frequency is low. -We think this because the primary side wiring off to the transformer from the IGBT PCB is just two “loose” wires, which form a much wider loop than they would if they were twisted pair. Also, the primary side IGBT and control PCB is all Thru hole. The PWM controller is a UC2845B. (I am guessing the output diodes of the transformer are inside the plastic enclosure which contains the transformer, i cant see them anywhere else)
The only feedback seen from isolated secondary to the primary is from a 7 way ribbon cable which runs about 40cm back to the primary side from the secondary...presumably the isolation of it is by two V0943B opto's which i can see on the primary side IGBT board.
Supposing you had a 24V, 100A isolated PSU. 3-phase input via 3 phase rectifier. (No neutral to rectifier). Post rectifier capacitance of 24uF (MAB MKP). Being switched by a fairly simple looking high frequency converter, with 4 primary side switching (1200V) IGBT’s (IXER35N120D1). Some kind of transformer of size approx. 12cmx7cmx6cm (can’t see it, its in plastic enclosure). The transformer is off the IGBT PCB, and is wired to it. The transformer’s isolated output goes a to bus bar pair on its way to the output capacitor bank (approx 20 x 35V 1200uF El caps) . As the bus bar pair makes it way to the output capacitor bank from the transformer, (quite a way, about 20cm) one of the bus bars has seven CS467090 sendust rings round it.
The other bus bar goes through a LEM LA306-S Current monitor.
CS467090 sendust rings
https://www.alibaba.com/product-det...-Transformers-CS467090-77442_62351494118.html
CS467090 sendust rings are Fe-Si-Al material. This surely does not have the high frequency properties necessary for use in this place? Wouldn’t you want NiZn rings? Why are the Sendust ones used?
I am guessing the switching frequency is low. -We think this because the primary side wiring off to the transformer from the IGBT PCB is just two “loose” wires, which form a much wider loop than they would if they were twisted pair. Also, the primary side IGBT and control PCB is all Thru hole. The PWM controller is a UC2845B. (I am guessing the output diodes of the transformer are inside the plastic enclosure which contains the transformer, i cant see them anywhere else)
The only feedback seen from isolated secondary to the primary is from a 7 way ribbon cable which runs about 40cm back to the primary side from the secondary...presumably the isolation of it is by two V0943B opto's which i can see on the primary side IGBT board.
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