Abstract: The present invention discloses a transmitting and receiving device for an ultrasonic system, which comprises a transmitter, a receiver and at least two switch circuits connected in series. The transmitter is coupled to an ultrasonic transducer and generates high voltage signals to the ultrasonic transducer during a transmitting mode. The receiver is coupled to the ultrasonic transducer via the at least two switch circuits and receives low voltage signals from the ultrasonic transducer during a receiving mode. The at least two switch circuits are configured to share voltage drop of the high voltage signals to isolate the high voltage signals during the transmitting mode and allow the low voltage signals to pass through during the receiving mode. It also discloses an ultrasonic system having the transmitting and receiving device.

Abstract: A fuel cell system is disclosed, which includes a fuel cell stack coupled to a load for providing power, a gas delivery system coupled to the fuel cell stack for providing fuel and oxygen to the fuel cell stack and a control system. The control system includes a forward controller for generating a desired control instruction signal based on a command from the load, and a correction controller for generating a control correction signal to avoid violating operational constraints of the fuel cell stack based on at least one measured signal from the fuel cell system. The control system generates a control signal based on the desired control instruction signal and the control correction signal, and controls the gas delivery system based on the generated control signal to ensure the fuel cell stack is operated within safe operating limits. A method for controlling the fuel cell system is also disclosed.

Abstract: An exemplary motor driving system includes a power source, a driving circuit, a controller, a motor, and a protection circuit. The driving circuit including at least one switching device coupled with the power source. The motor includes a plurality of windings. The motor is coupled with the driving circuit and driven by the driving circuit. The controller is configured to provide first switch signals to the at least one switching device of the driving circuit in a normal mode. The protection circuit is coupled with the controller, and configured to generate second switch signals based at least in part on a fault signal in a fault mode and provide the second switch signals to the at least one switching device of the driving circuit so as to reconstruct circuit loops between the driving circuit and the plurality of windings. A method for operating the motor driving system is also described.

Abstract: A fuel cell system is disclosed, which includes a fuel cell stack coupled to a load for providing power, a gas delivery system coupled to the fuel cell stack for providing fuel and oxygen to the fuel cell stack and a control system. The control system includes a forward controller for generating a desired control instruction signal based on a command from the load, and a correction controller for generating a control correction signal to avoid violating operational constraints of the fuel cell stack based on at least one measured signal from the fuel cell system. The control system generates a control signal based on the desired control instruction signal and the control correction signal, and controls the gas delivery system based on the generated control signal to ensure the fuel cell stack is operated within safe operating limits. A method for controlling the fuel cell system is also disclosed.

Abstract: An exemplary motor driving system includes a power source, a driving circuit, a controller, a motor, and a protection circuit. The driving circuit including at least one switching device coupled with the power source. The motor includes a plurality of windings. The motor is coupled with the driving circuit and driven by the driving circuit. The controller is configured to provide first switch signals to the at least one switching device of the driving circuit in a normal mode. The protection circuit is coupled with the controller, and configured to generate second switch signals based at least in part on a fault signal in a fault mode and provide the second switch signals to the at least one switching device of the driving circuit so as to reconstruct circuit loops between the driving circuit and the plurality of windings. A method for operating the motor driving system is also described.

Abstract: An exemplary motor driving system includes a power source, a driving circuit, a controller, a motor, and a protection circuit. The driving circuit including at least one switching device coupled with the power source. The motor includes a plurality of windings. The motor is coupled with the driving circuit and driven by the driving circuit. The controller is configured to provide first switch signals to the at least one switching device of the driving circuit in a normal mode. The protection circuit is coupled with the controller, and configured to generate second switch signals based at least in part on a fault signal in a fault mode and provide the second switch signals to the at least one switching device of the driving circuit so as to reconstruct circuit loops between the driving circuit and the plurality of windings. A method for operating the motor driving system is also described.

Abstract: A system for determining a real time solid flow rate of a solid-gas mixture is provided. The system includes multiple sensors, a data-fusion unit and an estimating unit. The sensors generate multiple measurement signals for obtaining at least two measured values of the real time solid flow rate. The data-fusion unit receives the measured values and establishes a state-space model based on the measured values. The estimating unit estimates the state-space model to generate an estimated value of the real time solid flow rate. A method for determining a real time solid flow rate of a solid-gas mixture is also presented.

Abstract: A control system for controlling a dry feed system to convey a solid fuel includes multiple sensors, a pressurizing gas controller, at least one assistant gas controller and multiple gas valves. The sensors generate multiple measurement signals signifying characteristics of the dry feed system. The pressuring gas controller calculates a feed tank pressure bias or/and a pressuring gas flow bias based on a solid flow rate and generates a first control signal based on the pressure bias or/and the pressurizing gas flow bias. The assistant gas controller calculates an assistant gas bias based on a solid loading ratio and generates a second control signal based on the assistant gas bias. The gas valves are driven by the first or/and second control signals to regulate the solid fuel. A control method is also described.

Abstract: An exemplary motor driving system includes a power source, a driving circuit, a controller, a motor, and a protection circuit. The driving circuit including at least one switching device coupled with the power source. The motor includes a plurality of windings. The motor is coupled with the driving circuit and driven by the driving circuit. The controller is configured to provide first switch signals to the at least one switching device of the driving circuit in a normal mode. The protection circuit is coupled with the controller, and configured to generate second switch signals based at least in part on a fault signal in a fault mode and provide the second switch signals to the at least one switching device of the driving circuit so as to reconstruct circuit loops between the driving circuit and the plurality of windings. A method for operating the motor driving system is also described.

Abstract: A system for determining a real time solid flow rate of a solid-gas mixture is provided. The system includes multiple sensors, a data-fusion unit and an estimating unit. The sensors generate multiple measurement signals for obtaining at least two measured values of the real time solid flow rate. The data-fusion unit receives the measured values and establishes a state-space model based on the measured values. The estimating unit estimates the state-space model to generate an estimated value of the real time solid flow rate. A method for determining a real time solid flow rate of a solid-gas mixture is also presented.

Abstract: A control system for controlling a dry feed system to convey a solid fuel includes multiple sensors, a pressurizing gas controller, at least one assistant gas controller and multiple gas valves. The sensors generate multiple measurement signals signifying characteristics of the dry feed system. The pressuring gas controller calculates a feed tank pressure bias or/and a pressuring gas flow bias based on a solid flow rate and generates a first control signal based on the pressure bias or/and the pressurizing gas flow bias. The assistant gas controller calculates an assistant gas bias based on a solid loading ratio and generates a second control signal based on the assistant gas bias. The gas valves are driven by the first or/and second control signals to regulate the solid fuel. A control method is also described.

Abstract: A simulating circuit (2), for testing a transit-time flowmeter (1) according to an embodiment of the invention, comprises an interface circuit (20) connecting with the transit-time flowmeter. The interface circuit receives driving signals from the transit-time flowmeter and generates a trigger signal on a rising or falling edge of the driving signals. An oscillator (21) outputs a clock signal. A delay generator (221) generates a preset time delay. A Digital to Analog Converter (DAC, 25) retrieves preset digitalized waveform. The DAC is enabled by the oscillator on ending of the preset time delay and converts the preset digitalized waveform into analog waveform output. The analog waveform output is sent back to the transit-time flowmeter, and thus a transit time or and a waveform through flowing fluids is simulated.