Thermal management optimization method for three-phase full-bridge converter compatible with single-phase rectification

Abstract

The invention discloses a thermal management optimization method for a three-phase full-bridge converter compatible with single-phase rectification, and the method comprises the following steps: S1, judging whether a power supply is a one-way power supply or a three-phase power supply after giving a voltage Udcref so as to close or open a kab, and closing ka and kc after the judgment is completed; s2, collecting the temperature of a three-phase switch tube and distributing the drive of the three-phase switch tube through a control loop; s3, controlling opening and closing of a three-phase switch tube serving as a live wire through a high-frequency modulation signal, and controlling opening and closing of a three-phase switch tube serving as a zero wire through a low-frequency modulation signal so as to control energy storage of an inductor and discharge to a capacitor Cdc; and S4, detecting the voltage Udc and feeding back the voltage Udc to the control loop, repeating the steps S2 and S3 until the voltage Udc is within the set voltage reference Udcref range, and outputting the final voltage Udc. According to the invention, the intelligent adjustment of the power of the three-phase switch tubes is realized, the temperature balance among the switch tubes is ensured by the soaking control strategy, and the equipment damage or performance reduction caused by local overheating is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of independent air duct modules, and in particular to a thermal management optimization method for a three-phase full-bridge converter compatible with single-phase rectification. Background Art

[0002] When the three-phase full-bridge rectifier is changed to single-phase rectifier, the C phase is used as the neutral line in the rectifier, and the A phase and the B phase are connected through the switch k ab Together as the live wire, R a With R c It is a three-phase pre-charging resistor, and can also be used as a pre-charging resistor for single-phase rectification. a With k c It is a pre-charging relay, which short-circuits the pre-charging resistor after the bus pre-charging is completed.

[0003] In the prior art, the S connected to the A phase is provided in the rectifier. a1 , S a2 , S connected to B b1 , S b2 , S connected to C c1 , S c2 All six switch tubes are modulated at high frequency, so S c1 With S c2 The switching loss of the switch tube and S a1 , S a2 , S b1 , S b2 The four switches are identical, but the conduction loss is four times greater, so the overall rectifier power is limited by S c1 With S c2 The current stress and heat generation of the switch tube are greatly reduced compared with the three-phase design, which makes the heat generation of the six switch tubes unbalanced. Summary of the invention

[0004] In view of the above-mentioned shortcomings, the present invention proposes a thermal management optimization method for a three-phase full-bridge converter compatible with single-phase rectification. The temperature of the three-phase switching tube is collected in real time by a temperature detector. The control loop can automatically allocate weighting coefficients according to the temperature information, thereby realizing intelligent adjustment of the power of the three-phase switching tube. This heat balance control strategy ensures the temperature balance between the switching tubes and avoids equipment damage or performance degradation caused by local overheating.

[0005] To achieve the above object, the present invention provides the following technical solution: a thermal management optimization method for a three-phase full-bridge converter compatible with a single-phase rectifier, wherein the rectifier includes a three-phase AC motor, a three-phase switch tube, a capacitor C dcThe three-phase lines of the three-phase AC motor are all provided with inductors, and the three-phase lines are connected to the three-phase bridge arms of the three-phase switch tube through the inductors. One end of the capacitor is connected to the first bus terminal of the three-phase switch tube, and the other end of the capacitor is connected to the second bus terminal of the three-phase switch tube. Two phase lines in the three-phase line are connected through k ab Control on and off to form a live line, a phase line as a neutral line and a phase line as a live line are provided with a pre-charging resistor and a pre-charging relay k for short-circuiting the pre-charging resistor a , k c , including the following steps:

[0006] S1: given voltage U dc_ref After that, determine whether the power supply is a unidirectional power supply or a three-phase power supply. If the power supply is a unidirectional power supply, close k ab , make the two connected phase lines as live wires and the remaining phase line as neutral wire. If the power supply is three-phase power supply, open k ab After the judgment is completed, close k a , k c ;

[0007] S2: Collect the temperature of the three-phase switch tube and distribute the drive of the three-phase switch tube through PI control and heat balance control of the control loop;

[0008] S3: The high-frequency modulation signal controls the opening and closing of the three-phase switch tube as the live line, and the low-frequency modulation signal controls the opening and closing of the three-phase switch tube as the neutral line, thereby controlling the energy storage of the inductor and the energy supplied to the capacitor C. dc discharge;

[0009] S4: By detecting the capacitance C dc The voltage U is obtained at both ends dc , and the voltage U dc Feedback to the control loop, repeat steps S2 and S3 until the voltage U dc When setting the voltage reference U dc_ref The final output voltage U dc .

[0010] As an improvement, the three-phase switch tube includes the A-phase switch tube S a1 With S a2 , B phase switch tube S b1 With S b , C phase switch tube S c1 With S c2 , the inductance includes L a , L b , L c , step S3 specifically includes the following steps: when the circuit is in the positive half cycle,

[0011] S3.1:S a2 Closed, S a1Open, inductance L a , L c To store energy;

[0012] S3.2:S a1 Closed, S a2 Open, inductance L a , L c The energy stored in S a1 With S c2 To bus capacitor C dc discharge;

[0013] S3.3:S b2 Closed, S b1 Open, inductance L b , L c To store energy;

[0014] S3.4:S b1 Closed, S b2 Open, inductance L b , L c The energy stored in S b1 With S c2 To bus capacitor C dc Discharge.

[0015] As an improvement, when the circuit is in the negative half cycle, the circuit control method is consistent with the control method when the circuit is in the positive half cycle.

[0016] As an improvement, S a1 With S a2 , S b1 With S b2 , S c1 With S c2 The bridge arms are connected to the control loop through temperature detectors, so that S a1 With S a2 , S b1 With S b2 The bridge arm automatically allocates weighting coefficients according to the temperature, so that S a1 With S a2 , S b1 With S b2 Two-phase temperature equilibrium, S c1 With S c2 The bridge arm limits power accordingly depending on the temperature.

[0017] As an improvement, the control loop includes a plurality of PI controllers, each of which is respectively connected to the capacitor C dc , S a1 With S a2 , S b1 With S b2 Connection to control rectifier voltage Udc 、A phase circuit current I a , B phase circuit current I b .

[0018] As an improvement, the PI controller samples the rectifier voltage U dc And according to the set voltage reference U dc_ref To adjust the rectifier voltage U dc , so that the rectifier voltage U dc Maintain the voltage reference U dc_ref range, generating a real power reference.

[0019] As an improvement, the temperature detector samples S c1 With S c2 The temperature of the bridge arm is tempC, and the adjustment coefficient T is obtained according to the range of tempC redu , when tempC is less than the maximum preset temperature t of the rectifier at full power output pre When the adjustment factor T redu is 1, when tempC is at the preset temperature t pre The protection temperature of the rectifier is pro When the adjustment factor is between redu Linear attenuation, adjustment coefficient T redu Multiplying it with the actual power reference yields the actual control power of the rectifier.

[0020] As an improvement, the temperature detector samples S a1 With S a2 , S b1 With S b2 The bridge arm temperatures are tempA and tempB, and the actual control power ratio is allocated according to tempA and tempB. When tempA is equal to tempB, the power coefficient T a and power factor T b Both are 0.5, that is, the actual control power is evenly distributed. When tempA and tempB are not equal, the power coefficient T a and power factor T b The distribution was performed according to the linear difference.

[0021] As an improvement, the S obtained by allocating tempA and tempB a1 With S a2 Bridge arm, S b1 With S b2 The actual control power of each bridge arm and the voltage reference U dc_ref Divide to get S a1 With S a2 The current control reference I a_ref and S b1With S b2 The current control reference I b_ref , and sample S through the PI controller a1 With S a2 The current of the bridge arm I a With S b1 With S b2 The current of the bridge arm I b and with the current control reference I a_ref With the current control reference I b_ref Contrast adjustment to control S a1 With S a2 , S b1 With S b2 The closing and opening of the switch tube.

[0022] Compared with the prior art, the advantages of the present invention are:

[0023] (1) The present invention is specially designed for independent air duct modules. Since independent air duct modules are not directly blown by fans, they have higher requirements for heat distribution. The temperature of the three-phase switch tube is collected in real time by the temperature detector. The control loop can automatically allocate weighting coefficients according to the temperature information, thereby realizing intelligent adjustment of the power of the three-phase switch tube. Under this control strategy, S c1 With S c2 No switching control signal is required, the switching loss is zero, and only conduction loss exists. a1 With S a2 , S b1 With S b2 There are both switching loss and conduction loss, but the conduction loss product is only S c1 With S c2 This heat distribution control strategy ensures the temperature balance between the switch tubes and avoids equipment damage or performance degradation caused by local overheating.

[0024] (2) Thermal management reduces the risk of switch failure due to overheating by balancing the temperature of the switch tube, thereby improving the reliability and stability of the entire converter, which helps to extend the service life of the equipment and reduce maintenance costs;

[0025] (3) Under heat distribution control, even if the temperature of a certain phase switch is high, the power output of other phase switches can be adjusted to ensure the stability and efficiency of the overall power output. This dynamic power allocation strategy enables the converter to use electrical energy more efficiently and reduce energy loss.

[0026] (4) This method is not only applicable to single-phase power supply, but also compatible with three-phase power supply, providing a flexible solution for different application scenarios. At the same time, through the coordination of high-frequency and low-frequency modulation signals, precise control of the inductor energy storage and discharge process is achieved, further enhancing the flexibility and response speed of thermal management.

[0027] (5) Heat dissipation control helps reduce the heat loss of the switch tube, thereby improving the efficiency of the entire system. This not only reduces energy consumption, but also reduces the need for additional cooling due to overheating, further reducing operating costs.

[0028] (6) This thermal management optimization method adopts a modular design, which makes system integration and subsequent maintenance more convenient. At the same time, due to the relatively simple control logic, it also reduces the system complexity and debugging difficulty. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0030] Figure 1 A flow chart of a thermal management optimization method for a three-phase full-bridge converter compatible with single-phase rectification;

[0031] Figure 2 is a schematic diagram of a rectifier circuit;

[0032] Figure 3 This is a schematic diagram of the current flow in the rectifier circuit in step S3.1;

[0033] Figure 4 This is a schematic diagram of the current flow in the rectifier circuit in step S3.2;

[0034] Figure 5 This is a schematic diagram of the current flow in the rectifier circuit in step S3.3;

[0035] Figure 6 This is a schematic diagram of the current flow in the rectifier circuit in step S3.4;

[0036] Figure 7 Schematic diagram of the temperature detector and its coordination process. DETAILED DESCRIPTION

[0037] like Figures 1 to 7 As shown, a thermal management optimization method for a three-phase full-bridge converter compatible with a single-phase rectifier is provided, wherein the rectifier includes an A-phase circuit, a B-phase circuit, a C-phase circuit, and a k-type circuit for controlling the on / off of the A-phase circuit and the B-phase circuit. ab , L set in the A phase circuit a , L set in the B phase circuit b , L set in the C phase circuit c , and L a Connected R a , and Lc Connected R c , control R a Short circuit k a , control R c Short circuit k c , and L a The series connected A phase switch tube S a1 With S a2 , and L b The series B phase switch tube S b1 With S b , and L c The series C phase switch tube S c1 With S c2 , capacitor C dc , S a1 With S a2 Switch tubes in parallel, S b1 With S b2 Switch tubes in parallel, S c1 With S c2 Switch tubes in parallel, S a1 , S b1 , S c1 After parallel connection with C dc One end of S a1 , S b2 , S c2 After parallel connection with C dc The other end of the connection, S a1 With S a2 , S b1 With S b2 , S c1 With S c2 The bridge arms are connected to the control loop through temperature detectors. The control loop includes several PI controllers. The several PI controllers are respectively connected to the capacitor C dc , S a1 With S a2 , S b1 With S b2 Connection to control rectifier voltage U dc 、A phase circuit current I a , B phase circuit current I b , including the following steps:

[0038] S1.1: given voltage U dc_ref After that, determine whether the power supply is a unidirectional power supply or a three-phase power supply. If the power supply is a unidirectional power supply, close k ab , make the A phase circuit and the B phase circuit as the live wire, and the C phase circuit as the neutral wire. If the power supply is a three-phase power supply, open k ab ;

[0039] S1.2: After the judgment is completed, slowly close k a , kc , so that R a , R c Short circuit;

[0040] S2.1: PI controller samples the rectifier voltage U dc And according to the set voltage reference U dc_ref To adjust the rectifier voltage U dc , so that the rectifier voltage U dc Maintain the voltage reference U dc_ref Within the range, an actual power reference is generated;

[0041] S2.2: Temperature detector sampling S c1 With S c2 The temperature of the bridge arm is tempC, and the adjustment coefficient T is obtained according to the range of tempC redu , when tempC is less than the maximum preset temperature t of the rectifier at full power output pre When the adjustment factor T redu is 1, when tempC is at the preset temperature t pre The protection temperature of the rectifier is pro When the adjustment factor is between redu Linear attenuation, adjustment coefficient T redu Multiplying it with the actual power reference yields the actual control power of the rectifier;

[0042] S2.3: The temperature detector samples S a1 With S a2 , S b1 With S b2 The bridge arm temperatures are tempA and tempB, and the actual control power ratio is allocated according to tempA and tempB. When tempA is equal to tempB, the power coefficient T a and power factor T b Both are 0.5, that is, the actual control power is evenly distributed. When tempA and tempB are not equal, the power coefficient T a and power factor T b Allocation is performed according to linear differences. Specifically, allocation according to linear differences is performed when T is satisfied. a +T b =1, the power coefficient is allocated according to the temperature difference percentage between tempA and tempB;

[0043] S2.4: S allocated according to tempA and tempB a1 With S a2 Bridge arm, S b1 With S b2 The actual control power of each bridge arm and the voltage reference U dc_ref Divide to get Sa1 With S a2 The current control reference I a_ref and S b1 With S b2 The current control reference I b_ref , and sample S through the PI controller a1 With S a2 The current of the bridge arm I a With S b1 With S b2 The current of the bridge arm I b and with the current control reference I a_ref With the current control reference I b_ref Contrast adjustment to control S a1 With S a2 , S b1 With S b2 Closing and opening of the switch tube;

[0044] When the circuit is in the positive half cycle, then:

[0045] S3.1:S a2 Closed, S a1 Open, inductance L a , L c To store energy;

[0046] S3.2:S a1 Closed, S a2 Open, inductance L a , L c The energy stored in S a1 With S c2 To bus capacitor C dc discharge;

[0047] S3.3:S b2 Closed, S b1 Open, inductance L b , L c To store energy;

[0048] S3.4:S b1 Closed, S b2 Open, inductance L b , L c The energy stored in S b1 With S c2 To bus capacitor C dc discharge;

[0049] When the circuit is in the negative half cycle, then:

[0050] S3.5:S a1 Closed, S a2 Open, inductance L a , Lc To store energy;

[0051] S3.6:S a2 Closed, S a1 Open, inductance L a , L c The energy stored in S a2 With S c1 To bus capacitor C dc discharge;

[0052] S3.7:S b1 Closed, S b2 Open, inductance L b , L c To store energy;

[0053] S3.8:S b2 Closed, S b1 Open, inductance L b , L c The energy stored in S b2 With S c1 To bus capacitor C dc discharge;

[0054] S4: By detecting the capacitance C dc The voltage U is obtained at both ends dc , and the voltage U dc Feedback to the control loop, repeat steps S2 and S3 until the voltage U dc When setting the voltage reference U dc_ref The final output voltage U dc .

[0055] The units described in some embodiments of the present disclosure may be implemented in software or hardware. The units described may also be arranged in a processor, and the functions described above may be at least partially performed by one or more hardware logic components.

[0056] The present invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A thermal management optimization method for a three-phase full-bridge converter compatible with single-phase rectification, characterized in that: The rectifier includes a three-phase AC motor, a three-phase switch tube, a capacitor C dc The three-phase lines of the three-phase AC motor are all provided with inductors, and the three-phase lines are respectively connected to the three-phase bridge arms of the three-phase switch tube through the inductors, one end of the capacitor is connected to the first bus terminal of the three-phase switch tube, and the other end of the capacitor is connected to the second bus terminal of the three-phase switch tube. Two phase lines of the three-phase line are connected through k ab Control on and off to form a live line, a phase line as a neutral line and a phase line as a live line are provided with a pre-charging resistor and a pre-charging relay k for short-circuiting the pre-charging resistor a , k c , including the following steps: S1: given voltage U dc_ref After that, determine whether the power supply is a unidirectional power supply or a three-phase power supply. If the power supply is a unidirectional power supply, close k ab , make the two connected phase lines as live wires and the remaining phase line as neutral wire. If the power supply is three-phase power supply, open k ab After the judgment is completed, close k a , k c ; S2: Collect the temperature of the three-phase switch tube and distribute the drive of the three-phase switch tube through PI control and heat balance control of the control loop; S3: The high-frequency modulation signal controls the opening and closing of the three-phase switch tube as the live line, and the low-frequency modulation signal controls the opening and closing of the three-phase switch tube as the neutral line, thereby controlling the energy storage of the inductor and the energy supplied to the capacitor C. dc discharge; S4: By detecting the capacitance C dc The voltage U is obtained at both ends dc , and the voltage U dc Feedback to the control loop, repeat steps S2 and S3 until the voltage U dc When setting the voltage reference U dc_ref The final output voltage U dc .

2. The thermal management optimization method for a three-phase full-bridge converter compatible with single-phase rectification according to claim 1, characterized in that: The three-phase switch tube includes an A-phase switch tube S a1 With S a2 , B phase switch tube S b1 With S b , C phase switch tube S c1 With S c2 , the inductor includes L a , L b , L c , the step S3 specifically comprises the following steps: when the circuit is in the positive half cycle, S3.1: The S a2 Closed, the S a1 Open, the inductor L a , L c To store energy; S3.2: The S a1 Closed, the S a2 Open, the inductor L a , L c The energy stored in S a1 With S c2 To bus capacitor C dc Discharge; S3.3: The S b2 Closed, the S b1 Open, the inductor L b , L c To store energy; S3.4: The S b1 Closed, the S b2 Open, the inductor L b , L c The energy stored in S b1 With S c2 To bus capacitor C dc Discharge.

3. The thermal management optimization method for three-phase full-bridge converter compatible with single-phase rectification according to claim 2, characterized in that: When the circuit is in the negative half cycle, the circuit control method is consistent with the control method when the circuit is in the positive half cycle.

4. The thermal management optimization method for a three-phase full-bridge converter compatible with single-phase rectification according to claim 2, characterized in that: The S a1 With S a2 , S b1 With S b2 , S c1 With S c2 The bridge arms are connected to the control loop through temperature detectors, so that the S a1 With S a2 , S b1 With S b2 The bridge arms automatically assign weighting coefficients according to the temperature, so that the S a1 With S a2 , S b1 With S b2 Two-phase temperature equilibrium, the S c1 With S c2 The bridge arm limits power accordingly depending on the temperature.

5. The thermal management optimization method for three-phase full-bridge converter compatible with single-phase rectification according to claim 4, characterized in that: The control loop includes a plurality of PI controllers, each of which is connected to a capacitor C dc , S a1 With S a2 , S b1 With S b2 Connection to control rectifier voltage U dc 、A phase circuit current I a , B phase circuit current I b .

6. The thermal management optimization method for three-phase full-bridge converter compatible with single-phase rectification according to claim 5, characterized in that: The PI controller samples the rectifier voltage U dc And according to the set voltage reference U dc_ref To adjust the rectifier voltage U dc , so that the rectifier voltage U dc Maintain the voltage reference U dc_ref range, generating a real power reference.

7. The thermal management optimization method for three-phase full-bridge converter compatible with single-phase rectification according to claim 6, characterized in that: The temperature detector samples S c1 With S c2 The temperature of the bridge arm is tempC, and the adjustment coefficient T is obtained according to the range of tempC redu , when tempC is less than the maximum preset temperature t of the rectifier at full power output pre When the adjustment coefficient T redu is 1, when tempC is at the preset temperature t pre The protection temperature of the rectifier is pro When the adjustment factor T redu It decays linearly, and the adjustment coefficient T redu Multiplying it with the actual power reference yields the actual control power of the rectifier.

8. The thermal management optimization method for three-phase full-bridge converter compatible with single-phase rectification according to claim 7, characterized in that: The temperature detectors respectively sample S a1 With S a2 , S b1 With S b2 The bridge arm temperatures tempA and tempB are calculated, and the actual control power ratio is allocated according to tempA and tempB. When tempA is equal to tempB, the power coefficient T a and power factor T b are all 0.5, that is, the actual control power is evenly distributed. When tempA and tempB are not equal, the power coefficient T a and power factor T b The distribution was performed according to the linear difference.

9. The thermal management optimization method for three-phase full-bridge converter compatible with single-phase rectification according to claim 8, characterized in that: The S obtained by allocating tempA and tempB a1 With S a2 Bridge arm, S b1 With S b2 The actual control power of each bridge arm and the voltage reference U dc_ref Divide to get S a1 With S a2 The current control reference I a_ref and S b1 With S b2 The current control reference I b_ref and sampled by the PI controller S a1 With S a2 The current of the bridge arm I a With S b1 With S b2 The current of the bridge arm I b and with the current control reference I a_ref With the current control reference I b_ref Contrast adjustment to control the S a1 With S a2 , S b1 With S b2 The closing and opening of the switch tube.

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