Methods and systems of compressor control with surge avoidance and response
OwnerJaroslav Pekar, Daniel Youssefinventors
Life of this patent
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Abstract
Methods and systems for surge control in a compressor system. A recirculation valve position may be actuated in response to identified conditions of potential surge, determined from a compressor map. Recirculation valve position may be controlled by calculating distance of current operating state to a surge line and using proportional integral control to manage the distance. Compressor speed command may be derated in response to identified surge, determined from one of speed fluctuations of the compressor speed, or variance of a compressor speed tracking error.
Claims13
A vapor cycle cooling system, the system using a circulating fluid and comprising a recirculation valve (RCV), a condenser, an expansion valve, an evaporator, a compressor motor, a compressor coupled to the motor and having a compressor inlet and a compressor outlet, an electronic control unit (ECU), and a plurality of pressure, temperature and motor sensors, the ECU configured to control the compressor motor by receiving a commanded speed, and controlling current to the motor or torque generated by the motor, the ECU further configured to perform a method of controlling the RCV comprising:
- estimating or sensing a mass flow rate through the compressor;
- estimating or sensing each of a first pressure upstream at the compressor inlet, and a second pressure at the compressor outlet;
- calculating a distance from a current operating point, using the mass flow rate and a ratio of the first and second pressures, to a surge line on a compressor map for the compressor;
- controlling position of the RCV with a controller taking the distance as an input;
- determining a parameter of motor operation;
- analyzing variance or oscillation of the parameter of motor operation to identify compressor surge;
- and
- determining whether compressor surge is occurring and, if so, derate compressor speed to reduce compressor speed below the commanded compressor speed;
- and
- wherein the parameter of motor operation is one of motor speed, motor torque, and motor current.
A method of controlling a recirculation valve in a compressor system, the compressor having an inlet and an outlet, and the recirculation valve coupled to the compressor system to controllably deliver fluid to the compressor inlet to increase mass flow therethrough, wherein the compressor is operable within conditions determined by a compressor map having a surge line, the compressor is coupled to a compressor motor and an engine control unit and the system comprises an electronic control unit (ECU);
- the method comprising:
- estimating or sensing a mass flow rate through the compressor;
- estimating or sensing each of a first pressure upstream at the compressor inlet, and a second pressure at the compressor outlet;
- calculating a distance from a current operating point, using the mass flow rate and a ratio of the first and second pressures, to the surge line on the compressor map;
- controlling position of the recirculation valve with a controller taking the distance as an input;
- the ECU controlling the compressor motor by receiving a commanded speed, and controlling current to the motor or torque generated by the motor;
- the ECU determining a parameter of motor operation;
- the ECU analyzing variance or oscillation of the parameter of motor operation to identify compressor surge;
- and
- the ECU determining that compressor surge is occurring and derating compressor speed to reduce compressor speed below the commanded compressor speed;
- wherein the parameter of motor operation is one of motor speed, motor torque, and motor current.
Dependencies are inferred from the claim text.