Solid state circuit breaker
A solid state circuit breaker has both solid state electronics and a physical switch. The solid state circuit breaker facilitates power measuring for end loads connected to a panel board circuit, e.g. receptacles, lighting, etc., over current protection, and disconnection all within one device. The solid state circuit breaker can be used at 100% of its rated capacity as opposed to 80% code-mandated limitation for thermal magnetic circuit breakers. The solid state circuit breaker also can provide power/current data (real-time) without the need of an additional device. The solid state circuit breaker further facilitates electronic, i.e. remote, opening, closing, and current limiting for demand response or load shedding.
1. A circuit breaker including a first terminal to receive an AC voltage and a second terminal to output the AC voltage, the circuit breaker comprising:
an electro-mechanical switch coupled to the first terminal to receive the AC voltage, wherein the electro-mechanical switch includes a physical switch that moves between an open position and a closed position, and an actuator for moving the physical switch between the open position and the closed position;
a solid state circuit breaker coupled to the electro-mechanical switch to receive the AC voltage, the solid state circuit breaker comprising an output, a coupled transistor pair, and a sensing circuit coupled to the coupled transistor pair, wherein the sensing circuit is configured to turn OFF the coupled transistor pair in response to receiving a trip signal; and
a controller circuit coupled to an input and an output of the solid state circuit breaker, wherein the controller circuit is configured to determine a fault condition at either the input or the output of the solid state circuit breaker, and in response to the fault condition, generate the trip signal and send the trip signal to the solid state circuit breaker and to the actuator, and wherein the physical switch is moved to the open position by the actuator in response to reception of the trip signal by the actuator,
wherein the solid state circuit breaker is controlled separately by the trip signal and by the output of the solid state circuit breaker independent of the controller.
2. The circuit breaker of claim 1 , wherein the solid state circuit breaker comprises:
a current limiting circuit activated by the trip signal;
the coupled transistor pair coupled to the current limiting circuit;
a driver circuit coupled to the coupled transistor pair; and
the sensing circuit coupled to the current limiting circuit and the driver circuit, wherein the sensing circuit is configured to sense a voltage drop in response to activation of the current limiting circuit, and wherein the driver circuit is configured to turn OFF the coupled transistor pair in response to the sensed voltage drop.
3. The circuit breaker of claim 2 , wherein the controller circuit is further coupled to the current limiting circuit, and wherein the current limiting circuit shunts current in response to receiving the trip signal, thereby resulting in the voltage drop sensed by the sensing circuit.
4. The circuit breaker of claim 3 , wherein the sensing circuit is further configured to sense the fault condition at either the input or the output of the solid state circuit breaker and to supply the fault condition to the driver circuit.
5. The circuit breaker of claim 4 , wherein the controller circuit, the current limiting circuit, the sensing circuit, and the driver circuit provide a first mechanism for turning OFF the coupled transistor pair in response to the fault condition.
6. The circuit breaker of claim 5 , wherein the sensing circuit and the driver circuit provide a second mechanism independent of the current limiting circuit and the controller circuit for turning OFF the coupled transistor pair in response to the fault condition.
7. The circuit breaker of claim 6 , wherein the first mechanism and the second mechanism provide redundancy within the solid state circuit breaker for turning OFF the coupled transistor pair in response to the fault condition.
8. The circuit breaker of claim 2 , wherein the current limiting circuit comprises a triac controlled by the trip signal.
9. The circuit breaker of claim 1 , wherein the electro-mechanical switch and the solid state circuit breaker provide redundancy within the circuit breaker for turning OFF current flow through the circuit breaker in response to the fault condition.
10. The circuit breaker of claim 1 , wherein the sensing circuit comprises:
a first comparator coupled to the first terminal and configured to output a first voltage difference corresponding to a first voltage characteristic; and
a second comparator coupled to the second terminal and configured to output a second voltage difference corresponding to a second voltage characteristic.
11. The circuit breaker of claim 1 , wherein the controller circuit is further configured to:
receive as input a remote control signal for turning OFF the solid state circuit breaker; and
generate the trip signal in response to the remote control signal.
12. The circuit breaker of claim 1 , wherein a first transistor of the coupled transistor pair is configured to enable current flow from the first terminal to the second terminal during a positive half-cycle of the AC voltage, and wherein a second transistor of the coupled transistor pair is configured to enable current flow from the first terminal to the second terminal during a negative half-cycle of the AC voltage.
13. A circuit breaker including a first terminal to receive an AC voltage and a second terminal to output the AC voltage, the circuit breaker comprising:
an electro-mechanical switch coupled to the first terminal to receive the AC voltage, wherein the electro-mechanical switch includes a physical switch that moves between an open position and a closed position, and an actuator for moving the physical switch between the open position and the closed position;
a solid state circuit breaker coupled to the electro-mechanical switch to receive the AC voltage, the solid state circuit breaker comprising an output, a coupled transistor pair, a current limiting circuit activated by a trip signal, and a sensing circuit coupled to the coupled transistor pair, wherein the sensing circuit is configured to turn OFF the coupled transistor pair in response to receiving the trip signal, and the current limiting circuit is configured to drop the voltage into the solid state circuit breaker in response to receiving the trip signal; and
a controller circuit coupled to an input and an output of the solid state circuit breaker, wherein the controller circuit is configured to determine a fault condition at either the input or the output of the solid state circuit breaker, and in response to the fault condition, generate the trip signal and send the trip signal to the solid state circuit breaker and to the actuator, and wherein the physical switch is moved to the open position by the actuator in response to reception of the trip signal by the actuator.
14. The circuit breaker of claim 13 , wherein the current limiting circuit shunts the voltage into the solid state circuit breaker to ground in response to receiving the trip signal.