US 12,463,433 B1
Distributed inertia-enhancement control method of the DC-bus voltage of a low-inertia DC microgrid
Nibedita Parida, Hong Kong (HK); and Chun Kit Cheung, Hong Kong (HK)
Assigned to Hong Kong Applied Science and Technology Research Institute Company Limited, Hong Kong (HK)
Filed by Hong Kong Applied Science and Technology Research Institute Company Limited, Hong Kong (HK)
Filed on Sep. 24, 2024, as Appl. No. 18/894,505.
Int. Cl. H02J 3/38 (2006.01); G05B 13/04 (2006.01); H02S 40/30 (2014.01)
CPC H02J 3/381 (2013.01) [G05B 13/04 (2013.01); H02J 2300/26 (2020.01); H02S 40/30 (2014.12)] 18 Claims
OG exemplary drawing
 
1. A virtual-inertia-enhanced low-inertia DC microgrid comprising:
a DC bus having a DC bus voltage;
a load drawing a load power from the DC bus;
a second DC-DC converter, connected to a photovoltaic (PV) array, that receives a PV current having a PV voltage from the PV array, the second DC-DC converter having power semiconductors controlled by second switching signals that convert the PV voltage to the DC bus volage on a second output;
a second output capacitor connected to the second output, wherein a second DC current generated by the second DC-DC converter flows into the second output capacitor, and a second load current flows out of the second output capacitor and onto the DC bus;
a second controller for generating the second switching signals to the second DC-DC converter to adjust the second DC current to maintain the DC bus voltage;
a second Virtual Inertia Enhancement Controller (VIEC) in the second contoller, the second VIEC causing the second controller to adjust the second switching signals in response to a difference of the second DC current and the second load current to enhance an effective capacitance of the second output capacitor;
a first DC-DC converter, connected to a battery, that receives a battery current having a battery voltage from the battery, the first DC-Dc converter having power semiconductors controlled by first switching signals that concert the battery volage to the DC bus voltage on a first output,
a first output capacitor connected to the first output, wherein a first DC current generated by the first DC-DC converter flows into the first output capacitor, and a first load current flows out of the first output capacitor and onto the DC bus;
a first controller for generating the first switching signals to the first DC-Dc converter to adjust the first DC current to maintain the DC bus voltages; and
a first Virtual Inertia Enhancement Controller (VIEC) in the first controller, the first VIEC causing the first controller to adjust the first switching signals in response to a difference of the first DC current and the first load current to enhance an effective capacitance of the first output capacitor;
wherein the second controller further comprises:
the second Virtual Inertia Enhancement Controller (VIEC) in the second controller, the second VIEC adjusting a second reference voltage in response to a difference of the second DC current and the second load current;
a second DC bus voltage controller that compares the DC bus voltage to the second reference voltage to generate a second reference current;
a second current controller that compares the PV current to the second reference current to generate a second pulsewidth control signal;
a second Pulse Width Modulation (PWM) generator that generates the second switching signals with pulsewidth controlled by the second pulsewidth control signal.