Methods and systems for controlling a compressor cooling system

1 . A compressor system comprising:

a compressor comprising:

a compressor housing defining a coolant inlet located on a low-pressure side of the compressor;

a shaft rotatably supported in the compressor housing; and

a motor operably connected to the shaft, wherein the compressor housing includes a motor coolant flow channel that delivers coolant to the motor;

a cooling circuit comprising:

a motor coolant supply line connected to the compressor housing to deliver coolant to the motor coolant flow channel, the motor coolant supply line including a motor coolant control valve to control coolant flow through the motor coolant supply line;

a coolant return line that receives coolant from the motor coolant flow channel and returns coolant to the coolant inlet or another portion of the compressor; and

a temperature sensor connected to the coolant return line to detect a coolant return temperature, the coolant return temperature being a temperature of the coolant return line or a temperature of coolant within the coolant return line; and

a controller having a processor and a memory, the controller connected to the temperature sensor and the motor coolant control valve, the memory storing instructions that when executed by the processor configure the controller to:

control the compressor to compress refrigerant delivered to the coolant inlet;

command the motor coolant control valve at a first time to open to provide a supply of coolant to the motor coolant flow channel;

receive a first detection of the coolant return temperature from the temperature sensor at the first time;

receive a second detection of the coolant return temperature from the temperature sensor at a second time after the first time;

determine, based on the first detection and the second detection of the coolant return temperature, if the motor coolant control valve opened at the first time by:

determining that the motor coolant control valve opened at the first time if the second detection of the coolant return temperature exceeds the first detection of the coolant return temperature by at least a threshold amount; and

determining that the motor coolant control valve did not open at the first time if:

the second detection of the coolant return temperature does not exceed the first detection of the coolant return temperature by the threshold amount; and

the second time is at least a time threshold after the first time; and

take remedial action when the controller determines that the motor coolant control valve did not open at the first time.

2 . The compressor system of claim 1 , wherein the threshold amount is a predetermined value.

3 . The compressor system of claim 2 , wherein the predetermined value is three degrees Fahrenheit.

4 . The compressor system of claim 1 , wherein the threshold amount has a variable value.

5 . The compressor system of claim 4 , wherein the threshold amount varies based at least in part on one or more of a value of the first detection of the coolant return temperature, a temperature of the motor, and an expected coolant flow rate.

6 . The compressor system of claim 1 , wherein the time threshold is a predetermined time after the first time.

7 . The compressor system of claim 6 , wherein the predetermined time is fifteen seconds.

8 . The compressor system of claim 1 , wherein the time threshold is a variable time after the first time.

9 . The compressor system of claim 1 , wherein the controller is configured to take remedial action by attempting again to open the motor coolant control valve.

10 . The compressor system of claim 1 , wherein the controller is configured to take remedial action by generating a warning that the motor coolant control valve did not open when the controller attempted to open it.

11 . The compressor system of claim 10 , wherein the controller is configured to store the warning in the memory for later retrieval.

12 . The compressor system of claim 10 further comprising a human cognizable output device, wherein the controller is configured to generate the warning by outputting a warning on the human cognizable output device.

13 . The compressor system of claim 10 , wherein the controller further comprises a communication interface, and the controller is configured to generate the warning by outputting an electronic warning to a remote device using the communication interface.

14 . The compressor system of claim 1 , wherein the controller is configured to take remedial action by stopping operation of the compressor.

15 . A method of operating a compressor system including a compressor, the method comprising:

controlling the compressor to compress refrigerant delivered to a coolant inlet of the compressor;

commanding a motor coolant control valve to open at a first time to provide a supply of coolant to a motor coolant flow channel that delivers coolant to a motor of the compressor;

receiving, at the first time, a first detection of a coolant return temperature from a temperature sensor connected to a coolant return line that receives coolant from the motor coolant flow channel and returns coolant to the coolant inlet or another portion of the compressor;

receiving a second detection of the coolant return temperature from the temperature sensor at a second time after the first time;

determining, based on the first detection and the second detection of the coolant return temperature, if the motor coolant control valve opened at the first time by:

determining that the motor coolant control valve opened at the first time if the second detection of the coolant return temperature exceeds the first detection of the coolant return temperature by at least a threshold amount; and

determining that the motor coolant control valve did not open at the first time if:

the second detection of the coolant return temperature does not exceed the first detection of the coolant return temperature by the threshold amount; and

the second time is at least a time threshold after the first time; and

attempting again to determine if the motor coolant control valve opened at the first time if:

the second detection of the coolant return temperature does not exceed the first detection of the coolant return temperature by the threshold amount; and

the second time is less than the time threshold after the first time; and

taking remedial action when the motor coolant control valve is determined not to have opened at the first time.

16 . The method of claim 15 , wherein attempting again to determine if the motor coolant control valve opened at the first time comprises:

receiving a third detection of the coolant return temperature from the temperature sensor at a third time after the first time;

determining that the motor coolant control valve opened at the first time if the third detection of the coolant return temperature exceeds the first detection of the coolant return temperature by at least the threshold amount;

determining that the motor coolant control valve did not open at the first time if:

the third detection of the coolant return temperature does not exceed the first detection of the coolant return temperature by the threshold amount; and

the third time is at least the time threshold after the first time; and

attempting again to determine if the motor coolant control valve opened at the first time if:

the third detection of the coolant return temperature does not exceed the first detection of the coolant return temperature by the threshold amount; and

the third time is less than the time threshold after the first time.

17 . The method of claim 15 , wherein taking remedial action when the controller determines that the motor coolant control valve did not open at the first time comprises at least one of attempting again to open the motor coolant control valve and generating a warning that the motor coolant control valve did not open when the controller attempted to open it.

18 . A method of operating a compressor system including a compressor, the method comprising:

controlling the compressor to compress refrigerant delivered to a coolant inlet of the compressor;

commanding a motor coolant control valve to open at a first time to provide a supply of coolant to a motor coolant flow channel that delivers coolant to a motor of the compressor;

receiving, at the first time, a first detection of a coolant return temperature from a temperature sensor connected to a coolant return line that receives coolant from the motor coolant flow channel and returns coolant to the coolant inlet or another portion of the compressor;

periodically receiving additional detections of the coolant return temperature from the temperature sensor;

determining, for each additional detection, if the additional detection exceeds a sum of the first detection and a threshold amount;

determining that the motor coolant control valve opened at the first time and stopping determining if the additional detection exceeds the sum when one of the additional detections exceeds the sum of the first detection and the threshold amount;

determining that the motor coolant control valve did not open at the first time and stopping determining if the additional detection exceeds the sum when none of the additional detections exceeds the sum of the first detection and the threshold amount and a predetermined length of time has passed after the first time; and

generating a warning when the motor coolant control valve is determined not to have opened at the first time.