Cross communication arrangement for multiple solid state power controller channels

#The present disclosure is related to multi-phase power switching, and more particularly to a cross-communicating multi-phase power control switch.

#Power distribution systems, such as aircraft AC power systems, often include a requirement that each of multiple phases be operated and controlled simultaneously by separate power channels. As a result of using separate channels, there can be short, undesirable, periods when some phases of the power distribution system are on and other phases are off. Communication between the controller (or controllers) in each power channel is utilized to synchronize the separate channels and to minimize these periods.

#In conventional systems, each of the power channels is referenced to a local reference voltage from a local power supply isolated from a reference voltage of the overall power distribution system. The independent power supply is referred to as a floating power supply. Due to the floating reference voltages, each solid state power controller cannot communicate directly with each other power controller without using an isolator circuit to isolate the communication signals from the reference voltage. The inclusion of an isolator circuit to connect each power controller in a power control switch to each other power controller in the power control switch, and thereby enable cross-communication between the controllers, is heavy and expensive. To get around this limitation, some existing power distribution systems connect each solid-state power controller to a systems level controller outside of the power control switch. This control method includes an additional time delay, and does not allow for all of the features that can be derived from direct cross-communication between each of the power controllers.

#FIG. 1 illustrates a highly schematic multi-phase power control switch.

#FIG. 2 illustrates a first alternate highly schematic, multi-phase power control switch.

#FIG. 3 illustrates a second alternate highly schematic multi-phase power control switch.

#FIG. 1 illustrates a highly schematic multi-phase power control switch 10 having three solid-state power controller (SSPC) channels 12a-c. Each of the illustrated SSPC channels 12 includes a single SSPC 14, although it is understood that additional SSPC's 14 can be included within each SSPC channel 12a-c. Each of the SSPCs 14 includes a microcontroller 20, such as a microprocessor. Each of the SSPCs 14 also includes an independent floating DC power supply 30 providing power to the microcontroller 20, and an isolator 50 connecting a cross-communication line 22 of the microcontroller 20 to a data bus 40. As each of the microcontrollers 20 is connected to the data bus 40, cross-communication between each microcontroller 20 and each other microcontroller 20 over the data bus 40 is enabled. Each of the microcontrollers 20 provides control commands 17 to individual power phase switches 16.

#To properly cross-communicate between the microcontrollers 20 and synchronize switching, one of the microcontrollers 20 is designated as the master microcontroller 20, and each of the remaining microcontrollers 20 is designated as a slave to the master microcontroller 20. In the illustrated example of FIG. 1, the microcontroller 20 of the center SSPC channel 12b is designated the master microcontroller, as indicated by the arrow directions on the connections to the data bus 40. The data bus 40, and the master-slave arrangement, allows the cross-communication and the coordination between each of the SSPC channels 12a-c and each of the SSPCs 14 within each SSPC channel 12a-c to be done locally between the SSPC channels 12a-c, without the need for a systems level controller to coordinate and synchronize the microcontrollers 20. Removing the systems level controller increases the response time of the cross-communication and increases the ability to implement timing critical controls within the multi-phase power control switch 10. This in turn supports synchronization of the controlled removal of power from each of the output power lines 18a, 18b and 18c.

#In the absence of a data bus 40, each of the microcontrollers 20 must be directly connected to each of the other microcontrollers 20 to enable cross communication between the microcontrollers 20. Each of the direct connections would require an isolator circuit 50 to prevent the varied reference voltage levels between the microcontrollers 20 from affecting performance of the power control switch 10. These different reference levels may be determined by differences of voltage between external power inputs 11,