A refrigeration machine controller function parameter automatic test system

Abstract

The application discloses a refrigerating machine controller function parameter automatic test system, which adopts a precision source table output voltage to simulate a refrigerating machine diode temperature measuring voltage, adopts a common three-phase direct-current brushless motor to replace the refrigerating machine as a load of the refrigerating machine controller, and adopts an oscilloscope to read a PWM duty cycle in a three-phase motor driving signal to judge a temperature control state, so that the test on temperature control function and temperature control voltage and other parameters of the refrigerating machine controller is realized. The system uses the common three-phase direct-current brushless motor with low price to replace the refrigerating machine with high price, and reduces the test cost.

Description

Technical Field

[0001] This invention discloses an automatic testing system for the functional parameters of a refrigeration unit controller, belonging to the field of refrigeration testing technology. Background Technology

[0002] The refrigeration unit controller is used for real-time control of the Stirling refrigerator motor's operating status. It is a refrigeration unit drive control circuit primarily used to control the refrigeration temperature. The controller acquires signals from the Stirling refrigerator's temperature-sensing diodes, processes them, and outputs a three-phase motor drive signal. Within the drive circuit unit, the motor speed is controlled by adjusting the PWM duty cycle, thereby controlling the Stirling refrigerator's cooling process and achieving temperature regulation. The controller's functional parameters include soft-start time, Hall effect power supply voltage, and temperature control voltage. Testing these parameters can improve product performance, ensure product quality, and increase production efficiency.

[0003] Existing technologies mostly focus on controlling and testing the motor of the refrigeration unit, with very few testing the corresponding functional parameters of the refrigeration unit controller. Summary of the Invention

[0004] The purpose of this invention is to provide an automatic testing system for the functional parameters of a refrigeration unit controller. The system uses the output voltage of a precision source meter to simulate the diode temperature measurement voltage of the refrigeration unit, and uses a common three-phase brushless DC motor to replace the refrigeration unit as the load of the refrigeration unit controller. An oscilloscope is used to read the PWM duty cycle in the three-phase motor drive signal to determine the module's temperature control status, thereby realizing the testing of the temperature control function and temperature control voltage of the refrigeration unit controller module.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] This invention provides an automatic testing system for the functional parameters of a refrigeration unit controller, comprising: a host computer, a programmable power supply, a serial port I / O relay, a precision source meter, a multimeter, an oscilloscope, and a three-phase DC brushless motor;

[0007] The three-phase brushless DC motor serves as the load for the refrigeration unit controller and is connected to the refrigeration unit controller.

[0008] The oscilloscope is connected to the three-phase motor drive signal output terminal of the refrigerator controller, and the oscilloscope is used to read the PWM duty cycle in the three-phase motor drive signal;

[0009] The precision source meter is connected to the refrigerator controller and is used to simulate the output of the refrigerator diode temperature measurement voltage to the refrigerator controller.

[0010] The multimeter is used to measure the temperature control voltage input to the refrigeration controller, and to measure the Hall power supply voltage output by the refrigeration controller.

[0011] The serial port I / O relay is used to control the switching of the connection channel between the multimeter and the refrigeration machine controller; the serial port I / O relay includes channel 1, channel 2, channel 3 and channel 4, channel 1 and channel 2 are used to connect the multimeter to the input port of the refrigeration machine controller; channel 3 and channel 4 are used to connect the multimeter to the output port of the refrigeration machine controller;

[0012] The programmable power supply is used to provide power support for the test system;

[0013] The oscilloscope, precision source meter, multimeter, serial port I / O relay, and programmable power supply are all connected to the host computer.

[0014] The host computer is used to obtain the PWM duty cycle in the three-phase motor drive signal under different operating conditions by controlling the output voltage of the precision source meter and the channel status of the serial port IO relay, and to test the Hall power supply voltage, soft start time and temperature control voltage of the chiller controller; and to control the working state of the programmable power supply.

[0015] Furthermore, the programmable power supply is used to provide 24V voltage to the refrigerator controller and to provide 24V voltage to the serial port I / O relay.

[0016] Furthermore, the oscilloscope, precision source meter, multimeter, serial port I / O relay, and programmable power supply are all connected to the host computer via USB interface.

[0017] Furthermore, the host computer is specifically used for,

[0018] The programmable power supply is controlled to supply power to the refrigeration machine controller, and the precision source meter is controlled to output a voltage of 0.9V to the refrigeration machine controller, so that the refrigeration machine controller starts working and starts timing;

[0019] The duty cycle of the PWM waveform in the three-phase motor drive signal measured by the oscilloscope is read at preset time intervals.

[0020] When the duty cycle η read reaches the duty cycle of full-speed operation, stop the timer and calculate the soft start time by subtracting the start time from the end timer.

[0021] If the calculated soft start time is within 2s to 4s, then the soft start time is considered acceptable.

[0022] Furthermore, the preset time interval is 500ms.

[0023] Furthermore, the host computer is specifically used for,

[0024] Send commands to open channel 1 and channel 2 to the serial port IO relay, so that the DCV and GND of the multimeter are connected to the D+ and D- input ports of the refrigerator controller;

[0025] The output voltage of a precision source meter is controlled to simulate the voltage output of the temperature-sensing diode in a refrigerator, which is then sent to the refrigerator controller; the initial output voltage is set to V. 始 =V 控 -0.02V; the V 控 This is the preset temperature control voltage for the refrigeration unit controller;

[0026] Adjust the output voltage of the precision source meter to put the refrigeration controller into temperature control mode;

[0027] Obtain the output voltage of a precision source meter measured by a multimeter when the refrigeration unit controller enters the temperature control state;

[0028] Compare the voltage value measured by the multimeter with the preset temperature control voltage. If the measured voltage value is within V... 控 If the voltage is within ±0.012V, the temperature control voltage is considered to be qualified.

[0029] Furthermore, adjust the output voltage of the precision source meter as follows to put the refrigeration controller into temperature control mode:

[0030] Read the PWM duty cycle η from the three-phase motor drive signal acquired by the oscilloscope;

[0031] If the duty cycle η reaches the preset temperature control duty cycle η 控 If the temperature is controlled, the refrigeration controller enters the temperature control state; otherwise, the output voltage of the precision source meter is increased.

[0032] Determine whether the increased output voltage reaches the stop voltage V. max ;

[0033] If the stopping voltage V is reached max If the test stops, then continue reading the PWM duty cycle from the three-phase motor drive signal acquired by the oscilloscope to determine whether the temperature control duty cycle η has been reached. 控 Until the refrigeration unit controller enters the temperature control state.

[0034] Furthermore, increase the output voltage of the precision source meter as follows:

[0035] After waiting 200ms, adjust the output voltage of the precision source meter to increase by 0.0003V.

[0036] Furthermore,

[0037] The stopping voltage is: V max =V 控 +0.02V, V max This is the stop voltage.

[0038] Furthermore, the host computer is specifically used for,

[0039] Send commands to open channels 3 and 4 to the serial port IO relay, so that the DCV and GND of the multimeter are connected to the output HV+ and HV- ports of the refrigerator controller;

[0040] The voltage across the HV+ and HV- terminals of the refrigeration controller measured by a multimeter is the Hall power supply voltage of the refrigeration controller.

[0041] Determine if the measured voltage value is between 4.8V and 9V. If it is, then the Hall power supply voltage of the refrigeration unit controller is qualified.

[0042] The beneficial effects of this invention are as follows:

[0043] This invention provides an automatic testing method for the functional parameters of a refrigeration unit controller. It employs the output voltage of a precision source meter to simulate the diode temperature measurement voltage of the refrigeration unit, and uses a standard three-phase brushless DC motor instead of the refrigeration unit as the load for the controller. An oscilloscope is used to read the PWM duty cycle in the three-phase motor drive signal to determine the module's temperature control status, thereby enabling the testing of the refrigeration unit controller module's temperature control function and parameters such as the temperature control voltage. This method uses an inexpensive standard three-phase brushless DC motor instead of a more expensive refrigeration unit, reducing testing costs. Furthermore, since the refrigeration unit requires a considerable amount of time to start up and reach the temperature control state, this method also significantly improves testing efficiency. Attached Figure Description

[0044] Figure 1 A schematic diagram of an automatic testing system for functional parameters of a refrigeration unit controller provided by the present invention;

[0045] Figure 2 This is a flowchart of the soft start time test in this invention;

[0046] Figure 3 This is a flowchart of the temperature control voltage test process in this invention. Detailed Implementation

[0047] The present invention will now be further described. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0048] Since both the three-phase brushless DC motor and the chiller are driven by three-phase drive signals and Hall effect signals, this invention uses the output voltage of a precision source meter to simulate the diode temperature measurement voltage of the chiller. A standard three-phase brushless DC motor is used instead of the chiller as the load for the chiller controller. An oscilloscope is used to read the PWM duty cycle in the three-phase motor drive signal to determine the temperature control status, thereby enabling the testing of the chiller controller's temperature control function and parameters such as the temperature control voltage. This method uses a low-cost standard three-phase brushless DC motor instead of a more expensive chiller, reducing testing costs. Furthermore, the chiller requires a considerable amount of time from startup to reaching the temperature control state, thus significantly improving testing efficiency.

[0049] Based on the above inventive concept, the present invention provides an automatic testing system for the functional parameters of a refrigeration unit controller, see [link to relevant documentation]. Figure 1 The system includes: host computer, programmable power supply, serial port I / O relay, precision source meter, multimeter, oscilloscope and three-phase DC brushless motor.

[0050] Specifically, the three-phase brushless DC motor serves as the load of the chiller controller and is connected to the chiller controller. The chiller controller outputs a three-phase motor drive signal and three Hall signals to the three-phase brushless DC motor, where the Hall signals are used to detect the position of the magnetic poles of the three-phase brushless DC motor.

[0051] An oscilloscope is connected to the three-phase motor drive signal output terminal of the refrigeration unit controller. The oscilloscope is used to read the PWM duty cycle in the three-phase motor drive signal.

[0052] A precision source meter, connected to the refrigeration unit controller, is used to simulate the diode temperature measurement voltage output of the refrigeration unit and send it to the controller. See also... Figure 1 The precision source meter is connected to the D+ and D- ports of the refrigeration unit controller.

[0053] A multimeter is used to measure the temperature control voltage input to the refrigeration controller, and to measure the Hall power supply voltage output by the refrigeration controller.

[0054] The serial port I / O relay is used to switch the connection mode for testing different indicators. When testing the temperature control voltage, it receives the command from the host computer to open channel 1 and channel 2, so that the DCV and GND of the multimeter are connected to the D+ and D- ports of the refrigerator controller. When testing the Hall power supply voltage, it receives the command from the host computer to open channel 3 and channel 4, so that the DCV and GND of the multimeter are connected to the HV+ and HV- ports of the refrigerator controller.

[0055] The programmable power supply is used to provide power support for the system. In this invention, the programmable power supply provides 24V voltage to the chiller controller and 24V voltage to the serial port IO relay.

[0056] The oscilloscope, precision source meter, multimeter, serial port I / O relay, and programmable power supply are all connected to the host computer via USB interface.

[0057] The host computer is used to obtain the PWM duty cycle in the three-phase motor drive signal under different operating conditions by controlling the output voltage of the precision source meter and the channel status of the serial port IO relay; to test the Hall power supply voltage, soft start time and temperature control voltage of the chiller controller; and to control the working status of the programmable power supply.

[0058] In this invention, a soft start time test is performed; see [link to relevant documentation]. Figure 2 The specific implementation process is as follows:

[0059] S1. The host computer controls the programmable power supply to power the refrigeration controller, and controls the precision source meter to output a voltage of 0.9V to the refrigeration controller, so that the refrigeration controller starts working and starts timing.

[0060] It should be noted that the serial port I / O relay does not need to be activated during this stage;

[0061] S2. The duty cycle of the PWM waveform in the three-phase motor drive signal measured by the oscilloscope is read by the host computer every 500ms.

[0062] S3, when the duty cycle η of the read operation is within η 全 When the duty cycle reaches (0.7~0.9), the motor reaches full speed and stops timing. The soft start time is calculated by subtracting the start time from the end time.

[0063] It should be noted that if the calculated slow start time is within 2 to 4 seconds, the indicator is considered acceptable.

[0064] In this invention, temperature control voltage testing is performed; see [link / reference]. Figure 3 The specific implementation process is as follows:

[0065] A1. Set the temperature control voltage of the refrigeration unit controller to V via the host computer's serial port. 控 For example, set the temperature control voltage to 1.047V, and then test the temperature control voltage; send a command to the serial port IO relay through the host computer to open channel 1 and channel 2, so that the DCV and GND of the multimeter are connected to the D+ and D- ports of the refrigeration controller, and use the multimeter to measure the voltage across D+ and D-.

[0066] A2. The output voltage of the precision source meter is adjusted by the host computer to simulate the voltage of the temperature sensing diode of the refrigerator and provide feedback voltage to the refrigerator controller. The initial voltage is set to V. 始 =V 控 -0.02V (i.e., 1.027V);

[0067] A3. By adjusting the output voltage of the precision source meter, the refrigeration controller is brought into temperature control mode;

[0068] A4. Measure the output voltage of the precision source meter when the refrigeration controller enters the temperature control state using a multimeter;

[0069] A5. Compare the voltage value measured by the multimeter with the preset temperature control voltage. If the measured voltage value is within V... 控 If the temperature control voltage is within ±0.012V (i.e., 1.035V to 1.059V), it is considered to be within the acceptable range.

[0070] In A3 above, by adjusting the output voltage of the precision source meter, the refrigeration controller is brought into temperature control mode. The specific operation process is as follows:

[0071] Read the PWM duty cycle η from the three-phase motor drive signal acquired by the oscilloscope;

[0072] If the duty cycle η does not reach the temperature control duty cycle η 控 If the value is (0.1~0.3), wait 200ms and then adjust the output voltage of the precision source meter to increase by 0.0003V.

[0073] Determine whether the adjusted output voltage reaches the stop voltage V. max =V 控 +0.02V (i.e., 1.067V);

[0074] If the stopping voltage V is reached max If the test stops, then continue reading the PWM duty cycle from the three-phase motor drive signal acquired by the oscilloscope to determine whether the temperature control duty cycle η has been reached. 控 If the temperature control duty cycle is reached, the refrigeration unit controller enters the temperature control state and stops increasing the output voltage of the precision source meter; otherwise, it continues to adjust and increase the output voltage of the precision source meter.

[0075] It should be noted that the temperature control duty cycle η 控 It is generally between 0.1 and 0.3, determined by the inherent properties of the refrigeration unit controller.

[0076] In this invention, considering testing efficiency, the initial output value of the source meter is set to 1.027V, which is 0.02V less than the set temperature control voltage. Then, it increases by 0.0003V every 200ms, with each small increase aimed at improving the accuracy of the test results. If the circuit malfunctions, the source meter output value will increase to a maximum of 1.067V, which is 0.02V more than the set temperature control voltage. If the refrigerator controller has not yet reached the temperature control state, the test will stop. The initial output voltage V of the precision source meter is set as follows: 始 Up to maximum output voltage V max The range is slightly larger than the normal temperature control voltage range (V). 控±0.012V ensures the accuracy and efficiency of the test.

[0077] In this invention, the Hall power supply voltage of the refrigeration unit controller is tested. The specific implementation process is as follows:

[0078] The host computer sends a command to the serial port IO relay to open channels 3 and 4, so that the DCV and GND of the multimeter are connected to the HV+ and HV- ports of the refrigerator controller.

[0079] Measure the voltage across the HV+ and HV- terminals of the refrigeration unit controller using a multimeter;

[0080] The host computer reads the voltage value measured by the multimeter through the serial port and determines whether the voltage value is between 4.8V and 9V. If it is, the indicator is considered qualified.

[0081] It should be noted that in this invention, LabVIEW is deployed in the host computer to implement functions such as output control of the test system instruments, automatic data acquisition, analysis and processing of the acquired data, and data storage.

[0082] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An automatic testing system for the functional parameters of a refrigeration unit controller, characterized in that, include: Host computer, programmable power supply, serial port I / O relay, precision source meter, multimeter, oscilloscope and three-phase DC brushless motor; The three-phase brushless DC motor serves as the load for the refrigeration unit controller and is connected to the refrigeration unit controller. The oscilloscope is connected to the three-phase motor drive signal output terminal of the refrigerator controller, and the oscilloscope is used to read the PWM duty cycle in the three-phase motor drive signal; The precision source meter is connected to the refrigerator controller and is used to simulate the output of the refrigerator diode temperature measurement voltage to the refrigerator controller. The multimeter is used to measure the temperature control voltage input to the refrigeration controller, and to measure the Hall power supply voltage output by the refrigeration controller. The serial port I / O relay is used to control the switching of the connection channel between the multimeter and the refrigeration machine controller; the serial port I / O relay includes channel 1, channel 2, channel 3 and channel 4, and channel 1 and channel 2 are used to connect the multimeter and the input port of the refrigeration machine controller; Channels 3 and 4 are used to connect the multimeter to the output port of the refrigeration controller; The programmable power supply is used to provide power support for the test system; The oscilloscope, precision source meter, multimeter, serial port I / O relay, and programmable power supply are all connected to the host computer. The host computer is used to obtain the PWM duty cycle in the three-phase motor drive signal under different operating conditions by controlling the output voltage of the precision source meter and controlling the channel status of the serial port IO relay; to test the Hall power supply voltage, soft start time and temperature control voltage of the chiller controller; and to control the working state of the programmable power supply. The host computer tests the soft-start time of the refrigeration unit controller, specifically... The programmable power supply is controlled to supply power to the refrigeration machine controller, and the precision source meter is controlled to output a voltage of 0.9V to the refrigeration machine controller, so that the refrigeration machine controller starts working and starts timing; The duty cycle of the PWM waveform in the three-phase motor drive signal measured by the oscilloscope is read at preset time intervals. When the duty cycle η read reaches the duty cycle of full-speed operation, stop the timer and calculate the soft start time by subtracting the start time from the end timer. If the calculated soft start time is within 2s to 4s, then the soft start time is considered acceptable.

2. The automatic testing system for functional parameters of a refrigeration unit controller according to claim 1, characterized in that, The programmable power supply is used to provide 24V voltage to the refrigerator controller and to the serial port I / O relay.

3. The automatic testing system for functional parameters of a refrigeration unit controller according to claim 1, characterized in that, The oscilloscope, precision source meter, multimeter, serial port I / O relay, and programmable power supply are all connected to the host computer via USB interface.

4. The automatic testing system for functional parameters of a refrigeration unit controller according to claim 1, characterized in that, The preset time interval is 500ms.

5. The automatic testing system for functional parameters of a refrigeration unit controller according to claim 1, characterized in that, The host computer is specifically used for, Send commands to open channel 1 and channel 2 to the serial port IO relay, so that the DCV and GND of the multimeter are connected to the D+ and D- input ports of the refrigerator controller; The output voltage of the precision source meter is controlled to simulate the voltage output of the temperature sensing diode of the refrigerator, which is then sent to the refrigerator controller; the initial output voltage is set as follows: V 始 =V 控 -0.02V; the V 控 This is the preset temperature control voltage for the refrigeration unit controller; Adjust the output voltage of the precision source meter to put the refrigeration controller into temperature control mode; Obtain the output voltage of a precision source meter measured by a multimeter when the refrigeration unit controller enters the temperature control state; Compare the voltage value measured by the multimeter with the preset temperature control voltage. If the measured voltage value is within V... 控 If the voltage is within ±0.012V, the temperature control voltage is considered to be qualified.

6. The automatic testing system for functional parameters of a refrigeration unit controller according to claim 5, characterized in that, Adjust the output voltage of the precision source meter as follows to put the refrigeration unit controller into temperature control mode: Read the PWM duty cycle η from the three-phase motor drive signal acquired by the oscilloscope; If the duty cycle η reaches the preset temperature control duty cycle η 控 Then the refrigeration unit controller enters the temperature control state; Otherwise, increase the output voltage of the precision source meter; Determine whether the increased output voltage reaches the stop voltage V. max ; If the stopping voltage V is reached max If the test stops, then continue reading the PWM duty cycle in the three-phase motor drive signal acquired by the oscilloscope to determine whether the temperature control duty cycle η has been reached. 控 Until the refrigeration unit controller enters the temperature control state.

7. The automatic testing system for functional parameters of a refrigeration unit controller according to claim 6, characterized in that, Increase the output voltage of the precision source meter as follows: After waiting 200ms, adjust the output voltage of the precision source meter to increase by 0.0003V.

8. The automatic testing system for functional parameters of a refrigeration unit controller according to claim 6, characterized in that, The stopping voltage is: V max = V 控 +0.02V, V max This is the stop voltage.

9. The automatic testing system for functional parameters of a refrigeration unit controller according to claim 1, characterized in that, The host computer is specifically used for, Send commands to open channels 3 and 4 to the serial port IO relay, so that the DCV and GND of the multimeter are connected to the output HV+ and HV- ports of the refrigerator controller; The voltage across the HV+ and HV- terminals of the refrigeration controller measured by a multimeter is the Hall power supply voltage of the refrigeration controller. Determine if the measured voltage value is between 4.8V and 9V. If it is, then the Hall power supply voltage of the refrigeration unit controller is qualified.

Images