Method of operating a bidirectional DC DC converter

A method of operating a bidirectional DC DC converter connected to a power source, an energy storage system and an energy usage system, in response to voltage and current measurements at connections from sensors and business rules, to cause (a) power output from the power source to be transferred to and stored in the energy storage system, (b) the power output to be transferred to the energy usage system, and (c) power stored in the energy storage system to be transferred to the energy usage system, wherein the converter comprises a controller that receives the voltage and current measurements, the method comprising:

• step 1.1 wherein the controller obtaining the business rules;
• step 1.2 wherein the controller, in response to the voltage and current measurements, determining impedance and power at the connections;
• step 1.3 wherein, if the controller determines:
• (a) that the power source is not outputting power, and in response to one of the business rules, that transfer of power from the energy storage system is not allowed, or (b) that the energy usage system is off, then the controller causing an impedance of the converter to be so large that no power is transferred from the energy storage system to the energy usage system;
• step 1.4 wherein, if the controller determines that the power source is outputting power, and in response to a second one of the business rules that all that power output is to be transferred to the energy usage system, then the controller causing the impedance of the converter to be so large that no power is transferred from the energy storage system to the energy usage system;
• step 1.5 wherein, if the controller determines:
• (a) that the power source is outputting power, and in response to a third one of the business rules that none of that power output is to be transferred to energy usage system, or (b) that the energy usage system is off and that no power is to transferred to or from the energy storage system, then the controller causing the impedance of the converter to be so large that no power is transferred from the power source to the energy storage system and no power is transferred from the energy storage system to the energy usage system;
• step 1.6 wherein, if the controller determines that the power source is outputting power, and in response to a fourth one of the business rules that that power output is to be transferred to the energy usage system and to the energy storage system, then the controller causing the impedance of the converter to be set so that amounts of power transferred are in accord with further business rules;
• and
• step 1.7 wherein, if the controller determines that the power source is not outputting power, and in response to a fifth one of the business rules that power is be transferred from the energy storage system to the energy usage system;
• the controller causing the impedance of the converter to be set so that power is transferred from the energy storage system to the energy usage system.