Electrical accumulator units with safe turn-off

An electrical accumulator unit comprising:

• a power storage device;
• a first switch connected to the power storage device;
• a power converter that includes a plurality of modular power converters connected in parallel with one another to transfer power between the power storage device and an output of the electrical accumulator unit, the power converter connected to the power storage device through the first switch, each of the plurality of modular power converters including a switch that is selectively turned On and Off to regulate the transfer of power between the power storage device and the output of the electrical accumulator unit;
• a dissipation circuit connected to the power converter;
• and
• a controller connected to control a state of the first switch and each of the plurality of switches associated with the plurality of modular power converters, wherein the controller turns the electrical accumulator unit Off by turning Off the first switch to disconnect the power storage device from the power converter, and turns each of the plurality of switches associated with the plurality of modular power converters to connect the dissipation circuit to the modular power converters in a recirculation circuit path that dissipates energy stored in the modular power converters.