HDI is the abbreviation of High-Density Interconnector. It is a kind of (technology) for the production of printed boards. It is a circuit board with a relatively high line distribution density using micro-blind and buried via technology. It is a compact product designed for small-capacity users. This modular design can be connected in parallel. One module has a capacity of 1000VA (1U in height) and is naturally cooled. It can be placed directly into the rack. Up to 6 modules can be connected in parallel. Using all-digital signal process control (DSP) technology and a number of patented technologies, it has a full range of adaptable load capacity and strong short-term overload capacity, regardless of load power factor and crest factor.