A gas bearing Stirling refrigerator drive control circuit and control method

Abstract

The invention discloses a gas bearing Stirling refrigerator drive control circuit and control method, belonging to the technical field of circuit design, and the scheme is: the input end of the H-bridge drive circuit is connected to the output end of the current compensation circuit and the power supply, the output end of the H-bridge drive circuit is connected to the refrigerator, the output end of the control circuit is connected to the input end of the H-bridge pre-drive circuit, and the output end of the H-bridge pre-drive circuit is connected to the H-bridge drive circuit; the refrigerator working current detection circuit is used to detect the working current value of the refrigerator, the input end of the refrigerator cold head temperature acquisition circuit is connected to the temperature sensor or platinum resistor installed on the refrigerator cold head, the input end of the refrigerator hot end temperature acquisition circuit is connected to the temperature sensor installed on the refrigerator hot end, and the output ends of the refrigerator working current detection circuit, the refrigerator cold head temperature acquisition circuit and the refrigerator hot end temperature acquisition circuit are all connected to the control circuit. The invention can ensure the safe operation and shutdown of the refrigerator.

Description

Technical Field

[0001] The invention relates to the technical field of circuit design, and in particular to a gas bearing Stirling refrigerator drive control circuit and a control method. Background Art

[0002] The existing gas bearing Stirling refrigerator drive controller uses an H-bridge inverter circuit, and the four electronic switch devices of the H-bridge use NMOS tubes. When working, the upper and lower switch tubes of the same bridge arm switch alternately. Due to the existence of the junction capacitance of the MOS tube itself, when the upper tube is turned on, the input voltage is added to the DS end of the lower tube, and the gate of the lower tube is charged through the junction capacitance. When the charging voltage reaches the gate turn-on voltage, the lower tube is turned on, causing the H-bridge circuit of the drive controller to be directly connected, and the drive controller is damaged. When the input voltage of the drive controller increases, the gate charging voltage is higher, and the H-bridge circuit is more likely to be directly connected.

[0003] In order to ensure that the refrigerator can still operate reliably when the input voltage increases, it is necessary to design a gas bearing Stirling refrigerator drive control circuit to ensure that the gate charging voltage of the NMOS tube will not exceed the turn-on voltage when the H-bridge input voltage increases, ensuring the reliable operation of the refrigerator. At the same time, it is prevented that the temperature rise of the refrigerator body is too high during the operation of the refrigerator, resulting in demagnetization and damage of the refrigerator. In addition, the drive controller needs to have the function of heating the cold head of the refrigerator, automatically heating the cold head of the refrigerator before the refrigerator is shut down, to prevent the cold head temperature of the refrigerator from being too low when shutting down, causing the refrigerator to generate electricity, thereby damaging the refrigerator. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the above-mentioned background technology and ensure the reliable operation of the refrigerator under the condition of increased voltage.

[0005] To achieve the above purpose, a gas bearing Stirling refrigerator drive control circuit is used, including: a current compensation circuit, an H-bridge drive circuit, a refrigerator, an H-bridge pre-drive circuit, a control circuit, a refrigerator working current detection circuit, a refrigerator cold head temperature collection circuit and a refrigerator hot end temperature collection circuit;

[0006] The input end of the H-bridge driving circuit is connected to the output end of the current compensation circuit and the power supply, the output end of the H-bridge driving circuit is connected to the refrigerator, the output end of the control circuit is connected to the input end of the H-bridge pre-driving circuit, and the output end of the H-bridge pre-driving circuit is connected to the H-bridge driving circuit;

[0007] The refrigerator working current detection circuit is used to detect the working current value of the refrigerator. The input end of the refrigerator cold head temperature acquisition circuit is connected to the temperature sensor or platinum resistor installed on the refrigerator cold head. The input end of the refrigerator hot end temperature acquisition circuit is connected to the temperature sensor installed on the hot end of the refrigerator. The output ends of the refrigerator working current detection circuit, the refrigerator cold head temperature acquisition circuit and the refrigerator hot end temperature acquisition circuit are all connected to the control circuit.

[0008] Furthermore, it also includes a refrigerator cold end heating circuit, the output end of the control circuit is connected to the refrigerator cold end heating circuit, and the output end of the refrigerator cold end heating circuit is connected to the heating resistor on the refrigerator cold head.

[0009] Further, the PWM signal output terminal of the control circuit is connected to the input terminal of the H-bridge pre-driving circuit, the output of the H-bridge pre-driving circuit is connected to the H-bridge driving circuit via resistors R1, R2, R3 and R4, and the resistors R1, R2, R3 and R4 are respectively connected to the G terminal and S terminal of four NMOS tubes in the H-bridge driving circuit;

[0010] The H-bridge driving circuit is connected to the input of the refrigerator via current measuring circuit 1 and current measuring circuit 2, and the outputs of current measuring circuit 1 and current measuring circuit 2 are connected to the control circuit.

[0011] Furthermore, the refrigerator cold head temperature acquisition circuit includes a variable resistor, an operational amplifier, a PMOS tube and resistors R5, R6, R7, R8 and R9, the variable resistor is connected in series with resistors R5, R6, R7, a resistor R8 is connected between the connecting line of resistors R6 and R7 and the sliding touch of the variable resistor, one end of the resistor R9 is connected to the inverting input of the operational amplifier, the connecting line of resistors R6 and R7 is connected to the non-inverting input of the operational amplifier, the output end of the operational amplifier is connected to the D pole of the PMOS tube, the S pole of the PMOS tube is connected to the temperature sensor or platinum resistor on the cold head of the refrigerator, and is connected to the input end of the control circuit.

[0012] Furthermore, the refrigerator hot end temperature acquisition circuit includes an integrated circuit temperature sensor AD590 and a resistor R10, the output end of the integrated circuit temperature sensor AD590 is connected in series with the resistor R10, and the output end of the integrated circuit temperature sensor AD590 is connected to the input of the control circuit.

[0013] Furthermore, the cold end heating circuit of the refrigerator includes a transistor, an NMOS tube and a heating resistor, the heating resistor is connected in series between the power supply and the D end of the NMOS tube, the G end of the NMOS tube is connected to the collector of the transistor, and the base of the transistor is connected to the input of the control circuit.

[0014] On the other hand, a control method for a gas bearing Stirling refrigerator drive control circuit is adopted, comprising the following steps:

[0015] The control circuit obtains the working current value, cold head temperature value and hot end temperature value of the refrigerator respectively through the refrigerator working current detection circuit, refrigerator cold head temperature acquisition circuit and refrigerator hot end temperature acquisition circuit;

[0016] The control circuit calculates a control amount according to the operating current value, the cold end temperature value and the hot end temperature value of the refrigerator, and controls the duty cycle of the PWM pulse of the H-bridge pre-driving circuit according to the control amount;

[0017] The H-bridge pre-driving circuit drives the H-bridge driving circuit to conduct alternately after performing logic direction control and amplification according to the PWM pulse, and the H-bridge driving circuit outputs an AC voltage to control the operation of the refrigerator.

[0018] Furthermore, before the refrigerator is shut down, the system further comprises:

[0019] The cold-end heating circuit of the refrigerator controls the power supply to be disconnected from the platinum resistor on the cold head of the refrigerator according to the high-level signal sent by the control circuit;

[0020] The refrigerator cold end heating circuit controls the power supply and the platinum resistor on the refrigerator cold head to close according to the low level signal sent by the control circuit.

[0021] Compared with the prior art, the present invention has the following technical effects: the refrigerator drive control circuit designed by the present invention completes the drive and control of the gas bearing Stirling refrigerator, proposes an H-bridge circuit safety drive design method, a circuit design method for accurately collecting the temperature values ​​of the cold head and hot end of the refrigerator, and a circuit design method for heating the cold head of the refrigerator, which solves the direct-through failure of the H-bridge drive circuit of the drive controller when the input voltage increases, enables the refrigerator to provide stable operation in a high steady-state temperature control environment for the outside world, protects the temperature rise of the refrigerator body from exceeding the set value, and ensures the safe operation and shutdown of the refrigerator. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings:

[0023] Figure 1 It is a principle block diagram of a gas bearing Stirling refrigerator drive control circuit;

[0024] Figure 2 It is the principle diagram of the driving and controlling body of the drive controller;

[0025] Figure 3 This is the principle diagram of the temperature collection of the cold head of the refrigerator;

[0026] Figure 4 This is the principle diagram of temperature collection at the hot end of the refrigerator;

[0027] Figure 5 This is the schematic diagram of the cold end heating of the refrigerator;

[0028] Figure 6 It is the temperature PID control block diagram;

[0029] Figure 7 It is the power PID control block diagram;

[0030] Figure 8 The present invention is a flow chart of a method for controlling a driving control circuit of a gas bearing Stirling refrigerator. DETAILED DESCRIPTION

[0031] In order to further illustrate the features of the present invention, please refer to the following detailed description and drawings of the present invention. The drawings are for reference and illustration only and are not intended to limit the scope of protection of the present invention.

[0032] like Figure 1 As shown, this embodiment discloses a gas bearing Stirling refrigerator drive control circuit, including: a current compensation circuit 1, an H-bridge drive circuit 2, a refrigerator 3, an H-bridge pre-drive circuit 4, a control circuit 6, a refrigerator working current detection circuit 7, a refrigerator cold head temperature acquisition circuit 8 and a refrigerator hot end temperature acquisition circuit 9;

[0033] The input end of the H-bridge driving circuit 2 is connected to the output end of the current compensation circuit 1 and the power supply, the output end of the H-bridge driving circuit 2 is connected to the refrigerator 3, the output end of the control circuit 6 is connected to the input end of the H-bridge pre-driving circuit 4, and the output end of the H-bridge pre-driving circuit 4 is connected to the H-bridge driving circuit 2;

[0034] The refrigerator working current detection circuit 7 is used to detect the working current value of the refrigerator 3. The input end of the refrigerator cold head temperature acquisition circuit 8 is connected to the temperature sensor or platinum resistor installed on the cold head of the refrigerator 3. The input end of the refrigerator hot end temperature acquisition circuit 9 is connected to the temperature sensor installed at the hot end of the refrigerator 3. The output ends of the refrigerator working current detection circuit 7, the refrigerator cold head temperature acquisition circuit 8 and the refrigerator hot end temperature acquisition circuit 9 are all connected to the control circuit 6.

[0035] Among them, the driving controller drives and controls the working process of the refrigerator as follows:

[0036] When the power is turned on, the control circuit 6 sends a SPWM pulse of a certain frequency to the H-bridge pre-driving circuit 4 through its dedicated PWM integrated circuit. The H-bridge pre-driving circuit 4 drives the switches in the H-bridge driving circuit 2 to work alternately, realizes DC-AC inversion, and drives the refrigerator 3 to work. The refrigerator cold head temperature acquisition circuit 8 collects the cold head temperature value through the temperature sensor installed on the cold head of the refrigerator 3 and sends it to the control circuit 6. The refrigerator hot end temperature acquisition circuit 9 collects the hot end temperature value through the temperature sensor installed on the hot end of the refrigerator 3 and sends it to the control circuit 6. The refrigerator working current detection circuit 7 detects the working current value of the refrigerator through the current detection chip and sends it to the control circuit 6. The control circuit 6 calculates the control amount through a certain software control algorithm with the above collected temperature value and current value, adjusts the corresponding SPWN pulse duty ratio according to the control amount, controls the switch opening and closing time to change the amplitude of the output AC voltage to realize the control of the refrigerator operation.

[0037] It should be noted that, since the refrigerator is an inductive load, the opening and closing of the switch in the H-bridge drive circuit 2 will inevitably cause the operating current of the refrigerator to jump. When the rising edge is steeper, the current is larger, and the driving current needs to absorb a large current from the power supply. When the output power of the power supply is limited, the current compensation circuit 1 needs to store energy to provide continuous current for the refrigerator. In addition, the current compensation circuit 1 completes the filtering of the interference pulse caused by the opening and closing of the switch in the drive circuit on the power bus.

[0038] Specifically, Figure 2 As shown, the PWM signal output end of the control circuit 6 is connected to the input end of the H-bridge pre-driving circuit 4, and the output of the H-bridge pre-driving circuit 4 is connected to the H-bridge driving circuit 2 via resistors R1, R2, R3 and R4, and the resistors R1, R2, R3 and R4 are respectively connected to the G end and S end of the four NMOS tubes in the H-bridge driving circuit 2;

[0039] The H-bridge driving circuit 2 is connected to the input of the refrigerator 3 via the current measuring circuit 1 and the current measuring circuit 2, and the outputs of the current measuring circuit 1 and the current measuring circuit 2 are connected to the control circuit 6.

[0040] Among them, the control circuit uses TI's TMS3202808 chip, the H-bridge pre-drive circuit uses the HIP4081 chip, and the current measurement circuit uses the ACS709 chip. The PWM signal generated by the control circuit is controlled and amplified by the pre-drive circuit to drive the four NMOS tubes of the H-bridge circuit to conduct in pairs and the upper and lower tubes of the same bridge arm are alternately conducted, and the output AC voltage drives the refrigerator to work. Current measurement circuit 1 and current measurement circuit 2 are used to detect the forward and reverse working current of the refrigerator and control the input power of the refrigerator. Resistors R1, R2, R3, and R4 are respectively connected to the GS ends of the four NMOS tubes in the H-bridge circuit to protect the NMOS tube from being in the off state. The DS terminal voltage is charged through the DG junction capacitor and the GS junction capacitor, causing the gate voltage to exceed the gate turn-on voltage, resulting in the upper and lower tubes of the same bridge arm being directly connected, thereby damaging the drive controller.

[0041] It should be noted that in order to overcome the existing gas bearing Stirling refrigerator drive controller using H-bridge inverter circuit, the four electronic switch devices of the H-bridge use NMOS tubes. When working, the upper and lower switch tubes of the same bridge arm switch alternately. Due to the existence of the junction capacitance of the MOS tube itself, when the upper tube is turned on, the input voltage is added to the DS end of the lower tube, and the gate of the lower tube is charged through the junction capacitance. When the charging voltage reaches the gate turn-on voltage, the lower tube is turned on, causing the H-bridge circuit of the drive controller to be directly connected, and the drive controller is damaged. When the input voltage of the drive controller increases, the gate charging voltage is higher, and the H-bridge circuit is more likely to be directly connected.

[0042] In this scheme, a resistor of appropriate resistance is added between the GS of the electronic switch tube NMOS in the H-bridge driving circuit to control the voltage at the G end of the NMOS not to increase, thereby avoiding direct connection of two switch tubes in the same bridge arm of the H-bridge driving circuit.

[0043] Specifically, Figure 3 As shown, the refrigerator cold head temperature acquisition circuit 8 includes a variable resistor, an operational amplifier, a PMOS tube and resistors R5, R6, R7, R8 and R9, the variable resistor is connected in series with the resistors R5, R6, R7, a resistor R8 is connected between the connecting line of the resistors R6 and R7 and the sliding touch of the variable resistor, one end of the resistor R9 is connected to the inverting input of the operational amplifier, the connecting line of the resistors R6 and R7 is connected to the positive input of the operational amplifier, the output end of the operational amplifier is connected to the D pole of the PMOS tube, the S pole of the PMOS tube is connected to the temperature sensor or platinum resistor on the cold head of the refrigerator 3, and is connected to the input end of the control circuit 6.

[0044] It should be noted that the role of the refrigerator cold head temperature acquisition circuit 8 in the entire refrigerator drive controller is to collect the refrigeration temperature value through the platinum resistor or diode temperature sensor installed on the refrigerator cold head, and feed it back to the control circuit. The control circuit controls the refrigerator input power according to the feedback temperature value to maintain the refrigerator cold head temperature in a highly stable state. It consists of five resistors, a variable resistor RX, an operational amplifier A and a PMOS tube to form a constant current source. The adjustable resistor RX is used to fine-tune the constant current. The constant current flows through the platinum resistor (the resistance of the platinum resistor changes with temperature), such as Figure 3 Sample the high-end voltage of the platinum resistor: VT=RI, and send the voltage value to the control circuit 6.

[0045] Specifically, Figure 4 As shown, the refrigerator hot end temperature acquisition circuit 9 includes an integrated circuit temperature sensor AD590 and a resistor R10, the output end of the integrated circuit temperature sensor AD590 is connected in series with the resistor R10, and the output end of the integrated circuit temperature sensor AD590 is connected to the input of the control circuit 6.

[0046] It should be noted that the role of the refrigerator hot-end temperature acquisition circuit 9 in the entire refrigerator drive controller is to collect the refrigerator hot-end temperature value through the integrated circuit temperature sensor installed at the refrigerator hot-end, and feed it back to the control circuit. The control circuit controls the refrigerator input power according to the feedback temperature value, so that the refrigerator hot-end temperature does not exceed the set value, preventing the refrigerator from overheating and damaging the refrigerator. In the refrigerator hot-end temperature acquisition circuit 9, for every 1 degree increase in temperature, the output current of the temperature sensor AD590 increases by 1 microampere, and the current flows through the resistor R as shown in FIG. Figure 4 As shown, the high-end voltage of the resistor is collected: VT=(1μ·R)V / K, and the voltage value is sent to the control circuit 6.

[0047] Furthermore, it also includes a refrigerator cold end heating circuit 5, the output end of the control circuit 6 is connected to the refrigerator cold end heating circuit 5, and the output end of the refrigerator cold end heating circuit 5 is connected to the heating resistor on the cold head of the refrigerator 3.

[0048] Specifically, the refrigerator cold end heating circuit 5 includes a transistor, an NMOS tube and a heating resistor, the heating resistor is connected in series to the power supply and the D end of the NMOS tube, the G end of the NMOS tube is connected to the collector of the transistor, and the base of the transistor is connected to the input of the control circuit 6.

[0049] It should be noted that the function of the cold end heating circuit 5 of the refrigerator is to heat the cold head through the heating resistor installed on the cold head of the refrigerator before the refrigerator is turned off, so as to ensure that the temperature of the cold head is greater than or equal to 90K when the refrigerator is turned off. The control circuit sends a high-level signal, the triode is turned on, the G end of the NMOS tube is low, the NMOS tube is turned off, and the circuit where the heating resistor is located is disconnected; on the contrary, the control circuit sends a low-level signal, the triode is disconnected, the G end of the NMOS tube is 12V high level, the NMOS tube is turned on, the circuit where the heating resistor is located is closed, the DC power supply and the heating resistor form a closed loop, and the cold head heating resistor is heated.

[0050] The PMOS is used as a constant current source to collect the temperature of the cold head of the refrigerator. The constant current stability is better, which improves the temperature control stability of the refrigerator. The circuit design method for collecting the hot end temperature value protects the hot end temperature of the refrigerator from exceeding the set value and protects the refrigerator. The circuit design method for heating the cold head of the refrigerator ensures that the refrigerator is shut down safely.

[0051] In order to ensure that the refrigerator can still operate reliably when the input voltage increases, the gate charging voltage of the NMOS tube will not exceed the turn-on voltage when the H-bridge input voltage increases, ensuring the reliable operation of the refrigerator, and avoiding excessive temperature rise of the refrigerator body during operation, which may cause demagnetization and damage to the refrigerator. This solution is designed with the function of heating the cold head of the refrigerator, which automatically heats the cold head of the refrigerator before the refrigerator is shut down, to prevent the cold head temperature of the refrigerator from being too low when shutting down, causing the refrigerator to generate electricity, thereby damaging the refrigerator.

[0052] like Figure 8 As shown, this embodiment discloses a control method for a gas bearing Stirling refrigerator drive control circuit, comprising the following steps S1 to S3:

[0053] S1, the control circuit 6 obtains the working current value, cold head temperature value and hot end temperature value of the refrigerator 3 through the refrigerator working current detection circuit 7, refrigerator cold head temperature acquisition circuit 8 and refrigerator hot end temperature acquisition circuit 9 respectively;

[0054] S2, the control circuit 6 calculates the control amount according to the working current value, the cold end temperature value and the hot end temperature value of the refrigerator 3, and controls the duty cycle of the PWM pulse of the H-bridge pre-driving circuit 4 according to the control amount;

[0055] S3, the H-bridge pre-driving circuit 4 performs logic direction control and amplification according to the PWM pulse to drive the H-bridge driving circuit 2 to be staggered, and the H-bridge driving circuit 2 outputs an AC voltage to control the refrigerator 3 to work.

[0056] Specifically, in the above step S2, the control circuit 6 controls the refrigerator input power according to the temperature value fed back by the refrigerator cold head temperature acquisition circuit 8, so that the refrigerator cold head temperature is maintained at a high stable state, specifically:

[0057] The control circuit 6 subtracts the cold head temperature T of the sampling refrigerator from the preset cold head temperature target value TK, and the obtained difference ek is used as the input of the PID controller. The cold head temperature PID control block diagram is as follows: Figure 6 As shown, according to the basic calculation formula of PID:

[0058]

[0059]

[0060] Among them, ek is the difference between the Kth cold head target value and the current sampled cold head temperature value, ek-1 is the difference between the K-1th cold head target value and the sampled cold head temperature value, and ek-2 is the difference between the K-2th cold head target value and the sampled cold head temperature value.

[0061] u k is the Kth output amplitude, u k-1 is the K-1th output amplitude, K p , K I , K D They are proportional coefficient, integral coefficient and differential coefficient respectively. These three coefficients are determined according to empirical values. u0 is the output constant. To reduce the amount of calculation, (1)-(2) is converted to:

[0062] Δu k =u k -u k-1

[0063] =K p (e k -e k-1 )+K I e k +K D (e k -2e k-1 +e k-2 )

[0064] u k =u k-1 +Δu k (3)

[0065] Add the calculated output amplitude change to the previous output to get the current output amplitude. O It is a SPWM wave with a frequency of 60HZ, and its amplitude is the output of the PID controller:

[0066] U O = sin A×(u k-1 +Δu k ) (4)

[0067] As shown in formula (4), when the PID output changes, the SPWM wave duty cycle changes, thereby adjusting the refrigerator input power.

[0068] Specifically, the process of the control circuit 6 controlling the temperature according to the hot-end temperature value of the refrigerator fed back by the hot-end temperature acquisition circuit 9 of the refrigerator is as follows: the hot-end temperature of the refrigerator is collected at intervals of 1 second and compared with the preset temperature value. If the hot-end temperature of the refrigerator exceeds the preset temperature for 10 seconds in a row, the controller jumps out of the temperature PID control and enters the over-temperature alarm control area, turns on the warning light alarm signal, and the controller enters the low-power protection working mode and switches to the high-speed constant-power PID control mode. If the hot-end temperature cannot be restored to below the preset temperature within 1 minute, the controller turns off the refrigerator drive signal, stops the refrigerator, and starts the alarm light and alarm bell drive signal at the same time, thereby protecting the refrigerator.

[0069] Specifically, the control circuit 6 performs power PID control such as Figure 7 As shown, the control circuit first presets a safe target power Wr, and then collects the input power of the refrigerator and subtracts it from the target power, the difference e r As the input of the power PID controller. According to the basic PID calculation formula:

[0070]

[0071]

[0072] where e r is the difference between the rth cold head target value and the current sampled cold head temperature value, e r-1 is the difference between the target value of the cold head and the sampled cold head temperature value for the r-1th time, e r-2 It is the difference between the cold head target value and the sampled cold head temperature value for the r-2th time.

[0073] u r is the rth output amplitude, u r-1 is the r-1 output amplitude, k p , k i , k d They are proportional coefficient, integral coefficient and differential coefficient respectively, and these three coefficients are determined according to empirical values. a is the output constant. Substituting (1)-(2) we get:

[0074] Δu r =u r -u r-1

[0075] =k p (e r -e r-1 )+k i e r +k d (er -2e r-1 +e r-2 )

[0076] u r =u r-1 +Δu r (3)

[0077] Calculate the output amplitude change and add it to the previous output to get the current output amplitude. r It is a SPWM wave with a frequency of 60HZ. Its amplitude is the output of the PID controller.

[0078] U r = sin A×(u r-1 +Δu r ) (4)

[0079] As shown in formula (4), when the PID output changes, the SPWM wave duty cycle changes, thereby adjusting the refrigerator input power.

[0080] Furthermore, before shutting down the refrigerator 3, the method further comprises:

[0081] The refrigerator cold end heating circuit 5 controls the power supply to be disconnected from the platinum resistor on the cold head of the refrigerator 3 according to the high level signal sent by the control circuit 6;

[0082] The refrigerator cold end heating circuit 5 controls the power supply and the platinum resistor on the cold head of the refrigerator 3 to close according to the low level signal sent by the control circuit 6 .

[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A gas bearing Stirling refrigerator drive control circuit, characterized in that: include: A current compensation circuit (1), an H-bridge driving circuit (2), a refrigerator (3), an H-bridge pre-driving circuit (4), a control circuit (6), a refrigerator operating current detection circuit (7), a refrigerator cold end temperature acquisition circuit (8), and a refrigerator hot end temperature acquisition circuit (9); The input end of the H-bridge driving circuit (2) is connected to the output end of the current compensation circuit (1) and the power supply, the output end of the H-bridge driving circuit (2) is connected to the refrigerator (3), the output end of the control circuit (6) is connected to the input end of the H-bridge pre-driving circuit (4), and the output end of the H-bridge pre-driving circuit (4) is connected to the H-bridge driving circuit (2); The refrigerator working current detection circuit (7) is used to detect the working current value of the refrigerator (3); the input end of the refrigerator cold head temperature acquisition circuit (8) is connected to a temperature sensor or a platinum resistor installed on the cold head of the refrigerator (3); the input end of the refrigerator hot end temperature acquisition circuit (9) is connected to a temperature sensor installed on the hot end of the refrigerator (3); and the output ends of the refrigerator working current detection circuit (7), the refrigerator cold head temperature acquisition circuit (8) and the refrigerator hot end temperature acquisition circuit (9) are all connected to the control circuit (6); The control method of the control circuit is specifically as follows: The control circuit (6) obtains the operating current value, the cold head temperature value and the hot end temperature value of the refrigerator (3) respectively via the refrigerator operating current detection circuit (7), the refrigerator cold head temperature acquisition circuit (8) and the refrigerator hot end temperature acquisition circuit (9); The control circuit (6) calculates a control amount according to the operating current value, the cold end temperature value and the hot end temperature value of the refrigerator (3), and controls the duty cycle of the PWM pulse of the H-bridge pre-driving circuit (4) according to the control amount; The H-bridge pre-driving circuit (4) drives the H-bridge driving circuit (2) to be switched on in an alternating manner after performing logic direction control and amplification according to the PWM pulse, and the H-bridge driving circuit (2) outputs an AC voltage to control the operation of the refrigerator (3).

2. The gas bearing Stirling refrigerator drive control circuit according to claim 1, characterized in that: It also includes a refrigerator cold end heating circuit (5), the output end of the control circuit (6) is connected to the refrigerator cold end heating circuit (5), and the output end of the refrigerator cold end heating circuit (5) is connected to the heating resistor on the cold head of the refrigerator (3).

3. The gas bearing Stirling refrigerator drive control circuit according to claim 1, characterized in that: The PWM signal output end of the control circuit (6) is connected to the input end of the H-bridge pre-driving circuit (4); the output of the H-bridge pre-driving circuit (4) is connected to the H-bridge driving circuit (2) via resistors R1, R2, R3 and R4; the resistors R1, R2, R3 and R4 are respectively connected to the G ends and S ends of four NMOS tubes in the H-bridge driving circuit (2); The H-bridge driving circuit (2) is connected to the input of the refrigerator (3) via current measuring circuit 1 and current measuring circuit 2, and the outputs of current measuring circuit 1 and current measuring circuit 2 are connected to the control circuit (6).

4. The gas bearing Stirling refrigerator drive control circuit according to claim 1, characterized in that: The refrigerator cold head temperature acquisition circuit (8) comprises a variable resistor, an operational amplifier, a PMOS tube and resistors R5, R6, R7, R8 and R9, the variable resistor is connected in series with the resistors R5, R6 and R7, a resistor R8 is connected between the connecting line between the resistors R6 and R7 and the sliding touch of the variable resistor, one end of the resistor R9 is connected to the inverting input of the operational amplifier, the connecting line between the resistors R6 and R7 is connected to the non-inverting input of the operational amplifier, the output end of the operational amplifier is connected to the D pole of the PMOS tube, the S pole of the PMOS tube is connected to the temperature sensor or platinum resistor on the cold head of the refrigerator (3), and is connected to the input end of the control circuit (6).

5. The gas bearing Stirling refrigerator drive control circuit according to claim 1, characterized in that: The refrigerator hot end temperature acquisition circuit (9) comprises an integrated circuit temperature sensor AD590 and a resistor R10, wherein the output end of the integrated circuit temperature sensor AD590 is connected in series with the resistor R10 and the output end of the integrated circuit temperature sensor AD590 is connected to the input of the control circuit (6).

6. The gas bearing Stirling refrigerator drive control circuit according to claim 2, characterized in that: The refrigerator cold end heating circuit (5) comprises a triode, an NMOS tube and a heating resistor, the heating resistor is connected in series to the power supply and the D end of the NMOS tube, the G end of the NMOS tube is connected to the collector of the triode, and the base of the triode is connected to the input of the control circuit (6).

7. The gas bearing Stirling refrigerator drive control circuit according to claim 2, characterized in that: Before shutting down the refrigerator (3), the method further comprises: The refrigerator cold end heating circuit (5) controls the power supply to be disconnected from the platinum resistor on the cold head of the refrigerator (3) according to the high level signal sent by the control circuit (6); The refrigerator cold end heating circuit (5) controls the power supply and the platinum resistor on the cold head of the refrigerator (3) to close according to the low level signal sent by the control circuit (6).

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