The invention relates to the technical field of 
converters, in particular to a traction-auxiliary converter for an internal 
combustion locomotive and a converter cabinet, and aims at solving the technical problems that an existing internal 
combustion AC transmission locomotive is low in integration level, poor in 
energy conservation and emission reduction effect and large in occupied locomotive space. The traction-auxiliary converter comprises a 
rectifier electrically connected with a main generator, the 
rectifier is connected with an intermediate direct-
current loop; a grounding detection module, a manual 
discharge module, a 
brake chopper and an 
inverter group which are connected in parallel are arranged in the intermediate direct-
current loop, the 
brake chopper is provided with a chopperbrake 
resistor, and the 
inverter group comprises an auxiliary fixed-frequency 
inverter, an auxiliary variable-frequency inverter and three traction inverters which are connected in parallel. The converter cabinet comprises two groups of 
converters, the auxiliary fixed-frequency inverters of the two groups of traction-auxiliary 
converters are electrically connected through a fixed-frequency expansion loop, and the auxiliary variable-frequency inverters of the two groups of traction-auxiliary converters are electrically connected through a variable-frequency expansion loop.