A method of controlling power supply of a caravan including a photovoltaic plate includes: receiving a first power parameter of an input interface element; determining whether there is a mains supply to be input into the input interface element according to the first power parameter; turning on a first switch to make the input interface element be electrically connected to the output interface element if the mains supply is input into the input interface element; receiving a power parameter of a battery pack if the mains supply is not input into the input interface element; determining whether a remaining power of the battery pack exceeds a power threshold according to the power parameter of the battery pack; and making the battery pack be electrically connected to an output interface element if the remaining power of the battery pack exceeds the power threshold.

A hybrid electric propulsion system may include an independent speed variable frequency (ISVF) generator coupled to an alternating current (AC) bus via a first switch. The system may further include a variable frequency independent speed (VFIS) motor coupled to the AC bus via a second switch, the system omitting circuitry to perform a full-power rated power conversion between the ISVF generator and the VFIS motor. The system may also include an alternating current direct current (AC/DC) converter coupled to the AC bus via a third switch. The system may include a battery coupled to the AC/DC converter.

A hybrid electric propulsion system may include an independent speed variable frequency (ISVF) generator coupled to an alternating current (AC) bus via a first switch. The system may further include a variable frequency independent speed (VFIS) motor coupled to the AC bus via a second switch, the system omitting circuitry to perform a full-power rated power conversion between the ISVF generator and the VFIS motor. The system may also include an alternating current direct current (AC/DC) converter coupled to the AC bus via a third switch. The system may include a battery coupled to the AC/DC converter.

A micro grid system comprises an adapter, a power controller, and secondary energy source. The adapter is in communication with an electric grid and configured to connect and disconnect a connection between the electric grid and a micro grid. The power controller is in communication with the adapter and configured to receive first AC power from the electric grid via the adapter, obtain grid information, and control the adapter to connect and disconnect the connection between the electric grid and the micro grid. The power controller controls the adapter to disconnect the connection in response to determining that the electric grid is abnormal based on the grid information. The secondary energy source is in communication with the power controller and is configured to generate DC power and to supply the DC power to the power controller.

A micro grid system comprises an adapter, a power controller, and secondary energy source. The adapter is in communication with an electric grid and configured to connect and disconnect a connection between the electric grid and a micro grid. The power controller is in communication with the adapter and configured to receive first AC power from the electric grid via the adapter, obtain grid information, and control the adapter to connect and disconnect the connection between the electric grid and the micro grid. The power controller controls the adapter to disconnect the connection in response to determining that the electric grid is abnormal based on the grid information. The secondary energy source is in communication with the power controller and is configured to generate DC power and to supply the DC power to the power controller.

A micro grid system comprises a secondary energy source and a power controller. The secondary energy source is associated with the micro grid, and the secondary energy source is configured to generate first DC power signal. The power controller is in communication with the secondary energy source and an electric grid, and configured to receive first AC power signal from the electric grid and the first DC power signal from the secondary energy source and to output a second AC power signal to loads in communication with the power controller. The power controller comprises a frequency converter configured to change frequency of the second AC power signal, a processor, and a memory configured to store instructions that, when executed, cause the processor to control the frequency converter to change the frequency of the second AC power signal.

A micro grid system comprises a secondary energy source and a power controller. The secondary energy source is associated with the micro grid, and the secondary energy source is configured to generate first DC power signal. The power controller is in communication with the secondary energy source and an electric grid, and configured to receive first AC power signal from the electric grid and the first DC power signal from the secondary energy source and to output a second AC power signal to loads in communication with the power controller. The power controller comprises a frequency converter configured to change frequency of the second AC power signal, a processor, and a memory configured to store instructions that, when executed, cause the processor to control the frequency converter to change the frequency of the second AC power signal.

Disclosed are an energy service system of a multi-machine production line and a control method thereof, the method includes reorganizing respective machines in the production line into three types of controllable entities: a drive system, an energy supply bus and an execution device, equipping them with a control center, and selecting a sub-drive system that is idle and is capable of completing the work stage with high energy efficiency to supply energy service for the corresponding execution device through the energy supply bus. Further disclosed is a design method of a multi-machine shared drive system of a production line, which increases the number of basic flow units of each drive unit to a maximum value one by one, and coordinates action time to form a variety of scheduling schemes, and selects a configuration scheme whose total time and total energy consumption are less as the shared drive system.

Disclosed are an energy service system of a multi-machine production line and a control method thereof, the method includes reorganizing respective machines in the production line into three types of controllable entities: a drive system, an energy supply bus and an execution device, equipping them with a control center, and selecting a sub-drive system that is idle and is capable of completing the work stage with high energy efficiency to supply energy service for the corresponding execution device through the energy supply bus. Further disclosed is a design method of a multi-machine shared drive system of a production line, which increases the number of basic flow units of each drive unit to a maximum value one by one, and coordinates action time to form a variety of scheduling schemes, and selects a configuration scheme whose total time and total energy consumption are less as the shared drive system.

A micro grid system comprises a secondary energy source and a power controller. The secondary energy source is associated with the micro grid, and the secondary energy source is configured to generate first DC power signal. The power controller is in communication with the secondary energy source and an electric grid, and configured to receive first AC power signal from the electric grid and the first DC power signal from the secondary energy source and to output a second AC power signal to loads in communication with the power controller. The power controller comprises a frequency converter configured to change frequency of the second AC power signal, a processor, and a memory configured to store instructions that, when executed, cause the processor to control the frequency converter to change the frequency of the second AC power signal.