The utility model provides a dc -to -ac converter is at ring testing arrangement, testing arrangement includes digital simulation analogue means, linear converting unit, and circuit control device is surveyed to controller and quilt, digital simulation analogue means respectively with linear converting unit with the controller links to each other, the linear change unit with it links to each other to be surveyed circuit control device, the controller with linear converting unit links to each other. The utility model provides a dc -to -ac converter is at ring testing arrangement can avoid safety problems such as high voltage and high current, saves the type test cost, improves detection efficiency, the type test testing result can be approached more accurately, the performance that truly is incorporated into the power networks of this dc -to -ac converter is reflected, logarithmic word volume signal carries out corresponding interpolation compensation simultaneously, improves hardware at the ring measuring accuracy.