A former employee of Bernard Madoff on trial for allegedly aiding the con man’s $17 billion fraud said he wrote corporate checks to himself for tens of thousands of dollars as a secret “bonus” from his boss, Bloomberg News reported yesterday. Daniel Bonventre, who oversaw Madoff’s broker-dealer and proprietary trading units, told investigators after Madoff’s arrest on Dec. 11, 2008, that Madoff permitted him to write such “vendor” checks to himself to hide his total annual compensation from other employees, Meaghan Schmidt, a consultant who helped unravel the fraud after its discovery, told jurors yesterday in Manhattan federal court. Starting in 1998, Bonventre signed similar checks to himself about once a year, ranging from about $45,000 to $60,000, said Schmidt, a director at the consulting firm AlixPartners LLP, whose employees took over Madoff’s offices in Midtown Manhattan to secure documents and ascertain where the business stood. One of the last such payments was a $50,000 check written the previous month, Schmidt said.