PIN self-adaptive ultrasonic welding system based on IGBT module

Abstract

The invention relates to an IGBT module-based PIN self-adaptive ultrasonic welding system, which comprises an IGBT module, a welding platform, an ultrasonic welding head, a driving assembly, an impedance detection assembly and a main control controller, and is characterized in that the welding platform fixes the IGBT module through an arranged clamp; the driving assembly drives the ultrasonic welding head to move; the ultrasonic welding head is driven by the driving assembly to move to the position where the PIN is in contact with the welding point position on the DCB, the contact pressure of the PIN and the welding point position on the DCB is within the preset process optimal pressure value range, ultrasonic welding is conducted on the PIN, and adjustment is conducted according to the current frequency and power of the ultrasonic welding head; the impedance detection assembly detects the contact impedance of the PIN and the ultrasonic welding head and outputs the contact impedance to the main control controller, so that the main control controller obtains an adjusting strategy mapped by the contact impedance information according to the received contact impedance information and outputs the adjusting strategy to the driving assembly. And the welding quality can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power semiconductor module packaging, and in particular to a PIN pin adaptive ultrasonic welding system based on an IGBT module. BACKGROUND

[0002] Insulated gate bipolar transistor (IGBT) modules, such as easy (EASY) type IGBT modules, are widely used in new energy, industrial driving and other fields due to their compact structure and flexible PIN pin array layout. The IGBT module is packaged by bridging the insulated gate bipolar transistor chip and the freewheeling diode chip through a specific circuit. The PIN pin is welded on the ceramic-based copper clad (DCB) plate at the bottom to achieve electrical and thermal connection. Therefore, the welding quality of the PIN pin directly affects the reliability and service life of the IGBT module. In related technologies, an ultrasonic welding method with fixed frequency and power parameters is used to weld the PIN pin to the DCB plate of the IGBT module, thereby using the PIN pin to achieve electrical and thermal connection of the IGBT module. However, this ultrasonic welding method, due to the use of fixed frequency and power parameters, cannot effectively cope with the length deviation, elasticity difference or inconsistent contact impedance of different batches of PIN pins, often resulting in virtual welding, partial welding or insufficient welding strength with the DCB plate. Especially in batch multi-PIN pin array operations, the effects of length deviation, elasticity difference or inconsistent contact impedance are particularly significant, resulting in poor welding quality and low welding reliability of the ultrasonic welding, thereby reducing the service life of the IGBT module. SUMMARY

[0003] Therefore, the present application provides a PIN pin adaptive ultrasonic welding system based on an IGBT module.

[0004] Specifically, the present application is realized by the following technical solutions: According to a first aspect of the present application, a PIN pin adaptive ultrasonic welding system based on an IGBT module is provided, comprising: an IGBT module, a welding platform, an ultrasonic welding head, a driving assembly, an impedance detection assembly and a main control controller, wherein, The welding platform is provided with a clamp for fixing the IGBT module by the clamp, so that the welding point of the DCB plate of the IGBT module corresponds to the PIN pin to be welded; The drive assembly includes an electric lead screw and a servo motor. The upper end of the electric lead screw is connected to a fixed servo motor, and the lower end of the electric lead screw is connected to the DCB plate of the ultrasonic welding head through a rigid or floating coupling. The electric lead screw is used to convert the rotational motion of the servo motor into the linear feed motion of the ultrasonic welding head in the vertical direction, so as to drive the ultrasonic welding head to move in the vertical direction. The servo motor performs corresponding rotational and displacement motions according to the adjustment commands output by the main controller. The ultrasonic welding head is connected to the lower end of the electric lead screw via a rigid or floating coupling. Driven by the linear feed motion of the electric lead screw, it moves to the position where the PIN needle contacts the welding point on the DCB board, ensuring that the contact pressure between the PIN needle and the welding point on the DCB board is within a preset optimal process pressure range. Based on the target frequency and target power output by the built-in frequency and power adjustment component, ultrasonic welding is performed on the PIN needle at the welding point on the DCB board. The target frequency and target power are obtained by the frequency and power adjustment component adjusting the ultrasonic welding head according to the ultrasonic parameter adjustment command output by the main controller. The impedance detection component is used to detect the contact impedance between the PIN pin and the ultrasonic welding head according to a preset impedance detection cycle after receiving the detection command output by the main controller, and output the detected contact impedance information to the main controller. The main controller is used to output detection commands to the impedance detection component after determining that ultrasonic welding is to be performed, receive contact impedance information transmitted by the impedance detection component, query the pre-set mapping relationship between contact impedance and adjustment strategy, obtain the adjustment strategy mapped by the contact impedance information, carry it in the adjustment command, and output it to the drive component.

[0005] Optionally, a crossbeam component is also provided above the welding platform, and an electric lead screw is mounted on the crossbeam component.

[0006] Optionally, the ultrasonic welding head further includes multiple welding sub-heads, wherein, Each welding head is connected to the built-in frequency and power regulation components; Each welding head forms a welding head array. Each welding head in the welding head array corresponds to a welding point in the welding point array laid out on the DCB board. Each welding head corresponds to one welding point. Each soldering head receives the target frequency and target power output from the frequency and power adjustment component for that soldering head, and performs ultrasonic soldering on the PIN pins at the corresponding soldering point on the DCB board. The main controller outputs an adjustment instruction set containing ultrasonic parameter adjustment instructions for each soldering head. The frequency and power adjustment component parses the received adjustment instruction set to obtain the target frequency and target power for each soldering head.

[0007] Optionally, each of the welding sub-heads corresponds to an electric screw rod and a servo motor.

[0008] Optionally, each of the PIN needles in the PIN needle array corresponds to an impedance detection component.

[0009] Optionally, in each of the welding sub-heads, an ultrasonic transducer is arranged, which is used to convert the target power output by the frequency and power adjusting component for the welding sub-head containing the target frequency into ultrasonic waves, so as to perform ultrasonic welding on the corresponding PIN needle.

[0010] Optionally, the master controller is further configured to, after determining to perform ultrasonic welding, assign a PIN needle identifier to each of the PIN needles in the PIN needle array, carry the PIN needle identifier in the detection instruction, and output the detection instruction to the impedance detection component of the corresponding PIN needle; based on the PIN needle array and the welding sub-head array, construct a correspondence between the PIN needle identifier and the driving component, and output the correspondence to the driving component; according to the PIN needle identifier carried in the received contact impedance information, carry the PIN needle identifier in the generated adjusting instruction, and output the adjusting instruction to the driving component corresponding to the PIN needle identifier carried in the contact impedance information. The impedance detection component is further configured to carry the PIN needle identifier of the detected PIN needle in the contact impedance information.

[0011] Optionally, the master controller is further configured to: According to the PIN needle identifier carried in the received contact impedance information, generate an impedance curve for the PIN needle identifier, wherein the impedance curve takes time as the horizontal coordinate and each time-received contact impedance information containing the PIN needle identifier as the vertical coordinate value.

[0012] Optionally, the PIN needle has the same or similar composition as that of the DCB plate at the welding point.

[0013] Optionally, the method further comprises: The vibration disc is provided with a gear, the PIN needle to be welded is placed in the vibration disc, the PIN needle is driven to transmit by using the vibration of the vibration disc, and the direction of the PIN needle in transmission is adjusted through the gear arranged on the vibration disc, so that the part of the PIN needle welded with the DCB plate is directed to the welding point.

[0014] The IGBT module-based PIN pin adaptive ultrasonic welding system in the technical solution comprises: an IGBT module, a welding platform, an ultrasonic welding head, a driving assembly, an impedance detection assembly and a main control controller, wherein the welding platform is provided with a clamp for fixing the IGBT module through the clamp, so that the welding point of the DCB board of the IGBT module corresponds to the PIN pin to be welded; the driving assembly comprises a motorized lead screw and a servo motor, wherein the upper end of the motorized lead screw is connected to the fixed servo motor, and the lower end of the motorized lead screw is connected to the DCB board of the ultrasonic welding head through a rigid or floating coupling; the motorized lead screw is used to convert the rotary motion of the servo motor into the linear feeding motion of the ultrasonic welding head in the vertical direction, so as to drive the ultrasonic welding head to move in the vertical direction; the servo motor performs corresponding rotary motion and displacement motion according to the adjustment instruction output by the main control controller; the ultrasonic welding head is connected to the lower end of the motorized lead screw through a rigid or floating coupling; under the driving of the linear feeding motion of the motorized lead screw, the ultrasonic welding head moves to a position where the PIN pin contacts the welding point on the DCB board, and the contact pressure of the PIN pin and the welding point on the DCB board is within a preset process optimal pressure value range; the ultrasonic welding of the PIN pin at the welding point on the DCB board is performed according to the target frequency and target power output by the built-in frequency and power adjustment assembly; the target frequency and target power are obtained by adjusting the current frequency and power of the ultrasonic welding head according to the ultrasonic parameter adjustment instruction received by the frequency and power adjustment assembly and output by the main control controller; the impedance detection assembly is used to detect the contact impedance of the PIN pin and the ultrasonic welding head according to a pre-set impedance detection period after receiving the detection instruction output by the main control controller, and output the detected contact impedance information to the main control controller; the main control controller is used to output the detection instruction to the impedance detection assembly after determining the ultrasonic welding, receive the contact impedance information transmitted by the impedance detection assembly, query the mapping relationship between the pre-set contact impedance and adjustment strategy, obtain the adjustment strategy mapped by the contact impedance information, carry the adjustment instruction, and output to the driving assembly. In this way, during the welding process of the PIN pin, the impedance detection assembly is used to detect the contact impedance information and feed back to the main control controller, and the main control controller determines the corresponding adjustment strategy according to the contact impedance information, so as to adjust the contact pressure, the ultrasonic wave power and the frequency used for the welding of the PIN pin, thereby improving the welding quality and welding reliability of the PIN pin through the real-time sensing of the welding state and the closed-loop regulation and control; further, since the PIN pin can be dynamically adjusted, the differences in length and elasticity of different batches of PIN pins can be adapted, thereby ensuring the consistency of the contact resistance of the PIN pin and the DCB board, effectively reducing the probability of false welding, partial welding or insufficient welding strength, and realizing the consistency of the contact impedance of different batches of PIN pins. BRIEF DESCRIPTION OF DRAWINGS

[0015] The accompanying drawings, which are incorporated into and form a part of the specification, illustrate an embodiment consistent with the present application and, together with the description, serve to explain the principles of the application.

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or the related description will be briefly introduced. Obviously, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without any creative effort.

[0017] Figure 1 A structural schematic diagram of a PIN pin adaptive ultrasonic welding system based on an IGBT module is provided for the embodiments of the present application. Figure 2 A feedback control unit schematic diagram in a PIN pin adaptive ultrasonic welding system based on an IGBT module is provided for the embodiments of the present application. DETAILED DESCRIPTION

[0018] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without any creative effort fall within the scope of protection of the present application.

[0019] In the related art, an ultrasonic welding method with fixed frequency and power parameters is used to weld PIN pins to a DCB board, and the electrical and thermal connection of an IGBT module is realized through the welded PIN pins. However, due to the differences in length and elasticity of PIN pins of different batches, the ultrasonic welding method with fixed frequency and power parameters cannot adapt to PIN pins with different parameters, and is prone to false welding, offset welding or insufficient welding strength, which results in poor welding quality and low welding reliability of PIN pins, and further affects the reliability and service life of the IGBT module.

[0020] In the embodiments, a structure-type integrated (adaptive ultrasonic welding) system for PIN pin array welding of an EASY type IGBT module is provided. The structure-type integrated system realizes adaptive ultrasonic welding in a structure integration manner, has adaptive parameter adjustment capability, can sense the welding state in real time and closed-loop control, so as to adapt to the differences in length and elasticity of PIN pins of different batches, guarantee the consistency of contact resistance with the DCB board, effectively reduce the probability of false welding, offset welding or insufficient welding strength, guarantee the consistency of contact impedance of PIN pins of different batches, and improve the welding quality and welding reliability of PIN pins.

[0021] Figure 1 A structure diagram of a PIN pin adaptive ultrasonic welding system based on an IGBT module is provided for an embodiment of the present application. As shown in the figure, it comprises an IGBT module 101, a welding platform 102, an ultrasonic welding head 103, a driving assembly 104, an impedance detection assembly 105 and a main control controller 106, wherein, Figure 1 The welding platform 102 is provided with a clamp for fixing the IGBT module 101 by the clamp, so that the welding point position of the DCB board of the IGBT module 101 corresponds to the PIN pin to be welded. In this embodiment, the EASY type IGBT module is pressed on the welding platform by the clamp, and the placement direction of the EASY type IGBT module is adjusted, so that the PIN pin sucked by the ultrasonic welding head can be welded to the corresponding point position of the DCB board at the bottom of the IGBT module.

[0022] In this embodiment, as an optional embodiment, the adaptive ultrasonic welding system further comprises: A vibrating disc (not shown in the figure) is provided with a gear, the PIN pin to be welded is placed in the vibrating disc, the PIN pin is driven to transmit by the vibration of the vibrating disc, and the direction of the PIN pin in transmission is adjusted by the gear provided on the vibrating disc, so that the part of the PIN pin welded with the DCB board is directed to the welding point position.

[0023] In this embodiment, the direction of the PIN pin is kept consistent by the gear provided on the vibrating disc, so as to ensure the accuracy of welding.

[0024] In this embodiment, the clamp provided on the welding platform is used to fix the EASY type IGBT module body, so that the welding point position keeps consistent with the arrangement of the PIN pin.

[0025] The driving assembly 104 comprises a motorized lead screw and a servo motor, wherein the upper end of the motorized lead screw is connected to the fixed servo motor, the lower end of the motorized lead screw is connected to the DCB board of the ultrasonic welding head 103 through a rigid or floating coupling, the motorized lead screw is used to convert the rotary motion of the servo motor into the linear feed motion of the ultrasonic welding head 103 in the vertical direction, so as to drive the ultrasonic welding head 103 to move in the vertical direction, and the servo motor performs corresponding rotary motion and displacement motion according to the adjustment instruction output by the main control controller 106; In this embodiment, as an optional embodiment, a cross beam member is further provided above the welding platform, and the motorized lead screw is arranged on the cross beam member.

[0026] In this embodiment, as an optional embodiment, a pressure control assembly is formed by the motorized lead screw and the servo motor, and the welding pressure of the PIN pin is adjusted by the pressure control assembly, so as to ensure that each PIN pin is subjected to consistent force.​

[0027] In this embodiment, the welding pressure of each PIN pin can be different, but it has a suitable optimal process pressure value. By using a pressure control component to adjust the welding pressure of each PIN pin to this optimal process pressure value, it can be ensured that each solder joint meets the uniform and stable welding quality requirements. As an optional embodiment, during the welding process of each PIN pin, through real-time detection, the main controller dynamically adjusts the position and welding pressure of the PIN pin based on the real-time detection results, and outputs adjustment commands to the servo motor. This causes the servo motor to perform corresponding rotational and displacement movements according to the adjustment commands output by the main controller, thereby controlling the ultrasonic welding head and ensuring that the welding pressure of each solder joint (PIN pin) reaches the optimal process pressure value.

[0028] In this embodiment, as an optional embodiment, the ultrasonic welding head is fixedly mounted on the pressure head fixing seat at the lower end of the electric lead screw via a rigid or floating coupling.

[0029] In this embodiment, since the ultrasonic welding head is fixed on the pressure head fixing seat at the end of the electric lead screw, it can move vertically along the vertical direction as the electric lead screw advances. As an optional embodiment, in the non-working state, the ultrasonic welding head is suspended above the PIN needle under the drive of the pressure control component. When entering the working state, the ultrasonic welding head performs a linear feed motion under the drive of the electric lead screw, contacts the upper surface of the PIN needle, and applies a set pressure, which is the optimal pressure value or the corresponding range of the process.

[0030] The ultrasonic welding head 103 is connected to the lower end of the electric lead screw via a rigid or floating coupling. Driven by the linear feed motion of the electric lead screw, it moves to the position where the PIN needle contacts the welding point on the DCB board, and ensures that the contact pressure between the PIN needle and the welding point on the DCB board is within the preset optimal process pressure range. Based on the target frequency and target power output by the built-in frequency and power adjustment component, ultrasonic welding is performed on the PIN needle at the welding point on the DCB board. The target frequency and target power are obtained by the frequency and power adjustment component adjusting the ultrasonic parameters according to the ultrasonic parameter adjustment command output by the main controller 106 and the current frequency and power of the ultrasonic welding head. In this embodiment, the movement of the electric lead screw ensures that the contact pressure (welding pressure) between the PIN pin and the welding point on the DCB board is within a preset optimal process pressure range, providing a stable welding environment for ultrasonic welding. Then, by adjusting the frequency and power, the contact pressure (welding pressure) is maintained within the preset optimal process pressure range, thereby ensuring the welding quality of ultrasonic welding. In this way, through linkage adjustment, each PIN pin is welded firmly, stably, and consistently.

[0031] In this embodiment, the ultrasonic welding head performs ultrasonic welding on the PIN pins. The ultrasonic welding head has multi-channel vibration capability; therefore, as an optional embodiment, the ultrasonic welding head also includes multiple welding sub-heads. Each welding head is connected to the built-in frequency and power regulation components; Each welding head forms a welding head array. Each welding head in the welding head array corresponds to a welding point in the welding point array laid out on the DCB board. Each welding head corresponds to one welding point. Each soldering head receives the target frequency and target power output from the frequency and power adjustment component for that soldering head, and performs ultrasonic soldering on the PIN pins at the corresponding soldering point on the DCB board. The main controller outputs an adjustment instruction set containing ultrasonic parameter adjustment instructions for each soldering head. The frequency and power adjustment component parses the received adjustment instruction set to obtain the target frequency and target power for each soldering head.

[0032] In this embodiment, as an optional embodiment, each welding head corresponds to an electric lead screw and a servo motor.

[0033] In this embodiment, an ultrasonic welding head is used to weld a PIN at a corresponding welding point. By using the vibration of the vibrating plate, the PIN is vacuum-extracted and moved to each welding point on the DCB board to form a welding point array (PIN array). The welding head array moves to the welding point array so that each welding head in the welding head array corresponds to each PIN in the welding point array, so as to perform batch welding on the corresponding PIN.

[0034] In this embodiment, a soldering head array is set up to correspond to the PIN pin array, with each soldering head corresponding to one PIN pin. As an optional embodiment, each soldering head is provided with an ultrasonic transducer. The ultrasonic transducer is used to convert the target power output by the power adjustment component for the soldering head containing the target frequency into ultrasonic waves to perform ultrasonic soldering on the corresponding PIN pin.

[0035] In this embodiment, each welding sub-head is driven by a corresponding ultrasonic transducer to form a multi-axis independent excitation structure, which is suitable for the parallel welding process of PIN pin array in EASY type IGBT module and effectively improves batch welding efficiency.

[0036] In this embodiment, as another optional embodiment, an ultrasonic welding head corresponds to a PIN pin array. The main controller obtains the current state of the PIN pin to be welded in the PIN pin array, adjusts the parameters of the ultrasonic welding head according to the obtained current state, and forms an ultrasonic parameter adjustment command for the PIN pin to be welded. This causes the ultrasonic welding head to move to the vibrating plate according to the ultrasonic parameter adjustment command to vacuum extract the PIN pin to be welded and perform the corresponding welding. In this way, the welding of all PIN pins in the PIN pin array is completed in sequence.

[0037] The impedance detection component 105 is used to detect the contact impedance between the PIN pin and the ultrasonic welding head 103 according to a preset impedance detection cycle after receiving the detection command output by the main controller 106, and output the detected contact impedance information to the main controller 106. In this embodiment, the impedance detection component includes, but is not limited to, an impedance sensor and an ultrasonic transducer. As an optional embodiment, the ultrasonic transducer acquires contact impedance information (feedback impedance information) such as acoustic impedance, electrical impedance, and vibration reflection between the ultrasonic welding head and the PIN pin, and outputs it to the main controller.

[0038] In this embodiment, as an optional implementation, for batch soldering, each pin in the pin array corresponds to an impedance detection component.

[0039] The main controller 106 is used to output a detection command to the impedance detection component 105 after determining that ultrasonic welding is to be performed, receive the contact impedance information transmitted by the impedance detection component 105, query the pre-set mapping relationship between contact impedance and adjustment strategy, obtain the adjustment strategy mapped by the contact impedance information, carry it in the adjustment command, and output it to the drive component 104.

[0040] In this embodiment, the mapping relationship between contact impedance and adjustment strategy can be based on the mapping relationship between the impedance difference between the detected contact impedance and the target impedance and the adjustment strategy. As an optional embodiment, the mapping relationship between impedance difference and adjustment strategy includes, but is not limited to: frequency adjustment, power adjustment, welding pressure fine adjustment and welding time adjustment.

[0041] In this embodiment, the main controller processes the contact impedance information collected from each PIN to obtain a contact impedance value, thereby identifying the current contact state of the PIN and whether the welding process is stable. Based on the mapping relationship between contact impedance and adjustment strategy, the main controller adjusts the frequency and power of the ultrasonic waves used for welding, as well as the downward pressure of the PIN, to ensure the consistency of welding multiple PINs. Thus, by collecting feedback impedance information along the path of the PIN, the main controller identifies the welding state of the PIN based on the feedback impedance information, determines whether the PIN is welded well, and adjusts the ultrasonic waves when the welding quality is poor. For example, it dynamically adjusts the ultrasonic power, welding time, and frequency used for welding, or adjusts key parameters such as the welding downward pressure of the PIN, until the solder joint meets the quality requirements.

[0042] In this embodiment, as an optional embodiment, the main controller is further configured to, after determining that ultrasonic welding will be performed, assign a PIN pin identifier to each PIN pin in the PIN pin array, carry the PIN pin identifier in the detection command, and output it to the impedance detection component of the corresponding PIN pin; construct a correspondence between the PIN pin identifier and the driving component based on the PIN pin array and the welding sub-head array, and output the correspondence to the driving component; and, based on the PIN pin identifier carried in the received contact impedance information, carry the PIN pin identifier in the generated adjustment command, and output the adjustment command to the driving component corresponding to the PIN pin identifier carried in the contact impedance information. The impedance detection component is also used to carry the pin identification of the detected pin in the contact impedance information.

[0043] In this embodiment, since the contact impedance information is related to the contact pressure (soldering pressure) applied by the PIN pins to the solder points on the DCB board, and the contact pressure can characterize the soldering reliability and quality of the PIN pins on the DCB board, this embodiment utilizes the contact impedance information characterizing soldering reliability and quality. The main controller adjusts the displacement and speed of the servo motor based on the contact impedance information between the PIN pins and the solder points on the DCB board provided by the impedance detection component. Ultimately, the pressure applied to each PIN pin is within the preset optimal process pressure range, thereby ensuring the soldering quality and reliability of the PIN pins and thus improving the service life of the IGBT module.

[0044] In this embodiment, as an optional implementation, each PIN in the PIN array corresponds to an impedance detection component. The main controller, based on the contact impedance information provided by the impedance detection component, drives the soldering head to move accordingly by adjusting the displacement and speed of the servo motor. The movement of the soldering head causes a change in the contact resistance between the PIN and the soldering point. This change is detected by the impedance detection component and fed back to the main controller. The main controller then readjusts the displacement and speed of the servo motor based on the changed contact impedance information until the contact impedance information detected by the impedance detection component is within a preset contact impedance range. This ensures that the pressure applied to each PIN is within a preset optimal process pressure range (e.g., 3N~15N). In this way, by detecting the contact impedance information for each PIN and configuring the corresponding drive component and soldering head, poor contact caused by inconsistent PIN height or substrate warping can be effectively avoided, ensuring the reliability of PIN soldering.

[0045] In this embodiment, the PIN pins in the EASY type IGBT module include, but are not limited to, through-hole silver-plated PIN pins and nickel-copper-plated PIN pins. As an optional embodiment, the composition of the PIN pins is the same as or similar to that of the DCB board at the soldering point. For example, if the DCB board contains nickel-copper, then nickel-copper-plated PIN pins are selected. In this way, after ultrasonic soldering, the PIN pins and the DCB board are a fusion of the same components, without any chemical change. Therefore, no additional resistance value is generated during the soldering process, thereby improving the conductivity of the IGBT module. Simultaneously, ultrasonic soldering also increases the tensile force between the PIN pins and the DCB board, thereby enhancing the mechanical stability of the IGBT module. For the PIN pin array, the length tolerance between each PIN pin is approximately ±0.1mm. Through the above structure, the pressure of each PIN pin in the PIN pin array can be adjusted point-by-point evenly, avoiding the influence of length tolerance on the soldering quality. It can also accommodate the slight height differences in the DCB board between different soldering areas caused by warping, avoiding misaligned soldering and floating soldering.

[0046] Figure 2 This is a schematic diagram of a feedback control unit in a PIN adaptive ultrasonic welding system based on an IGBT module, provided as an embodiment of the present invention. Figure 2 As shown, the feedback control unit includes a drive component 104, an impedance detection component 105, and a main controller 106. The impedance detection component 105 transmits the detected contact impedance information to the main controller 106. The main controller 106 generates an adjustment command based on the difference between the received contact impedance information and the target impedance information, and outputs it to the drive component 104. The drive component 104 obtains the corresponding adjustment amount according to the adjustment command and performs the corresponding adjustment.

[0047] The workflow of the IGBT module-based adaptive ultrasonic welding system for pins in this embodiment is briefly described below: The IGBT-based PIN adaptive ultrasonic welding system starts and initializes. After the main controller activates the PIN welding task, the electric lead screw, driven by a servo motor, drives the ultrasonic welding head down and moves it to the set position above the PIN array. The impedance detection component uses an impedance sensor to sample signals such as voltage V(t) and current I(t) in real time to detect the impedance of the contact between the PIN and the ultrasonic welding head. The main controller determines the current coupling state between the PIN and the ultrasonic welding head based on the impedance detection results (Z(t) = V(t) / I(t)). Based on the pre-set mapping relationship between contact impedance and adjustment strategy, such as a pre-set experience base / model containing the mapping relationship between contact impedance and adjustment strategy, it determines whether the welding completion conditions are met based on the current coupling state. If the welding completion conditions are not met, an adjustment strategy based on the contact impedance information mapping is obtained. The servo motor is controlled according to the obtained adjustment strategy. The servo motor drives the electric lead screw, which drives the ultrasonic welding head to slowly press down and contact the top of the PIN pin. Subsequently, after detecting that the contact pressure between the ultrasonic welding head and the PIN pin is within the optimal pressure range of the process, the ultrasonic welding head performs welding through ultrasonic vibration. As an optional embodiment, if it is determined that the current coupling state does not meet the welding completion conditions, the main controller outputs a command to extend the welding time or increase the excitation amplitude until the current coupling state meets the welding completion conditions.

[0048] If the welding completion conditions are met, that is, the contact impedance information detected by the impedance detection component drops to the preset optimal process pressure value range and remains within the optimal process pressure value range for a preset time, the welding is confirmed to be complete. The current coupling state meets the welding completion conditions, the main controller controls the servo motor to reverse, drives the electric lead screw to reverse, and the electric lead screw drives the ultrasonic welding head to automatically lift in preparation for the welding of the next PIN.

[0049] In this embodiment, as an optional embodiment, the main controller is further configured to: Based on the PIN identifier carried in the received contact impedance information, an impedance curve is generated for the PIN identifier. The impedance curve is plotted with time on the horizontal axis and the contact impedance information containing the PIN identifier received at each time on the vertical axis.

[0050] In this embodiment, by recording the contact impedance information of each PIN during the soldering process, the soldering process can be traced back to its source and used as a reference for subsequent soldering quality analysis.

[0051] The following is a specific embodiment, and then the adaptive ultrasonic welding system of this embodiment will be described in detail.

[0052] In this embodiment, assuming the PIN array is 2x2, the contact impedance corresponding to the optimal process pressure range is 3 ohms to 4 ohms, the welding head array is a multi-channel structure (corresponding to welding PIN1 to PIN4 respectively), and the impedance detection component is an array-type impedance detection component. The array-type impedance detection component samples the contact impedance information of each PIN. Assuming the contact impedances of the four PINs (denoted as PIN1 to PIN4) when in contact with the welding point are 5 ohms, 10 ohms, 2 ohms, and 6 ohms respectively, and the impedance detection period is set to 5 to 10 ms, the specific process of real-time adjustment of ultrasonic frequency and excitation power is as follows: The main controller calculates the impedance difference ΔZ = current impedance - target impedance (optimal pressure range for the process) and generates compensation parameters based on the impedance difference. The frequency / power of the welding head can be independently adjusted based on the impedance difference corresponding to that welding head. For PIN2 (Z=10 ohms), the difference with the target impedance is the largest, indicating the worst coupling. The corresponding adjustment strategy is to increase the excitation power by 10~20% and at the same time, slightly reduce the frequency to enhance energy penetration. For PIN3 (Z=2 ohms), the impedance is close to but less than the target impedance, indicating good coupling. The corresponding adjustment strategy is not to increase the power (keep the power constant) and to adjust the frequency to the optimal frequency, for example, 20kHz. For PIN1 and PIN4 (Z=5 ohms and 6 ohms), which are close to but greater than the target impedance, the corresponding adjustment strategy is to adjust the frequency matching slightly in small steps according to the preset frequency, while increasing the excitation power by +5~10%. Every 5-10ms, the array-type impedance sensing component samples the contact impedance information of each pin and refreshes the impedance feedback. If the contact resistance of PIN2 does not decrease, the corresponding adjustment strategy is to automatically extend the dwell time or fine-tune the amplitude. If the contact impedance of PIN3 still decreases, the corresponding adjustment strategy is to determine that the current coupling state is in the "solder penetration" state, control the corresponding soldering head to rise early, and after controlling the soldering head to rise early, the contact impedance detection will no longer be triggered.

[0053] Once the contact resistance of all pins has dropped to the range of 3 ohms to 4 ohms, the soldering of the pin array is considered complete, and the soldering of the next pin array can begin.

[0054] In this embodiment, during the soldering process, the contact impedance information of each PIN is fed back in real time. If a PIN does not reach the target impedance, it is dynamically corrected by extending the excitation time or adjusting the amplitude method, so as to ensure that the solder joint impedance of all PINs at the soldering point is within the target impedance.

[0055] Compared with the prior art, the adaptive ultrasonic welding system of this embodiment has the following advantages and positive effects: 1. Achieve consistent control of multi-pin array soldering, with single-point soldering resistance fluctuation less than ±10%; In this embodiment, by adjusting comprehensive parameters such as ultrasonic frequency, power, welding pressure, and welding time, the contact resistance fluctuation during welding is controlled within ±10%. As an optional embodiment, the focus is on adjusting the ultrasonic frequency and power, combined with multi-dimensional parameter adjustments such as welding pressure and welding time, and a closed-loop control is formed based on impedance feedback, thereby achieving the engineering goal of "resistance fluctuation ≤ ±10%".

[0056] 2. It has significant adaptive adjustment capabilities, enabling it to adapt to the differences in physical properties between different batches of PIN pins; 3. It can avoid problems such as resonance shift and welding floating, thus improving the first-pass yield; In this embodiment, frequency adjustment and soldering pressure control work in tandem to effectively avoid resonant frequency shifts and soldering float problems caused by differences in PIN pin structure, pad height fluctuations, or transducer load changes. Impedance feedback identifies changes in coupling state in real time, and dynamically adjusts frequency, power, and soldering pressure during excitation to ensure that the PIN pins maintain effective contact and resonant matching, thereby significantly improving soldering consistency and reliability.

[0057] 4. Modular structure, facilitating rapid deployment and maintenance in automated production lines; 5. It can be extended to other high-density pin devices, packaging modules, and other soldering process scenarios.

[0058] The embodiments of the subject matter and functional operation described in this specification can be implemented in the following ways: digital electronic circuits, tangibly embodied computer software or firmware, computer hardware including the structures disclosed in this specification and their structural equivalents, or combinations thereof. Embodiments of the subject matter described in this specification can be implemented as one or more computer programs, i.e., one or more modules of computer program instructions encoded on a tangible, non-transitory program carrier for execution by a data processing apparatus or for controlling the operation of a data processing apparatus. Alternatively or additionally, the program instructions may be encoded on artificially generated propagation signals, such as machine-generated electrical, optical, or electromagnetic signals, which are generated to encode information and transmit it to a suitable receiving device for execution by the data processing apparatus. The computer storage medium may be a machine-readable storage device, a machine-readable storage substrate, a random or serial access memory device, or combinations thereof.

[0059] The processing and logic flow described in this specification can be executed by one or more programmable computers that execute one or more computer programs to perform corresponding functions by operating on input data and generating output. The processing and logic flow can also be executed by special-purpose logic circuitry—such as FPGA (Field Programmable Gate Array) or ASIC (Application-Specific Integrated Circuit), and the device can also be implemented as special-purpose logic circuitry.

[0060] Suitable computers for executing computer programs include, for example, general-purpose and / or special-purpose microprocessors, or any other type of central processing unit. Typically, the central processing unit receives instructions and data from read-only memory and / or random access memory. The basic components of a computer include a central processing unit for implementing or executing instructions and one or more memory devices for storing instructions and data. Typically, a computer will also include one or more mass storage devices for storing data, such as disks, magneto-optical disks, or optical disks, or the computer will be operatively coupled to such mass storage devices to receive data from or transfer data to them, or both. However, a computer is not required to have such devices. Furthermore, a computer can be embedded in another device, such as a mobile phone, a personal digital assistant (PDA), a mobile audio or video player, a game console, a global positioning system (GPS) receiver, or a portable storage device such as a universal serial bus (USB) flash drive, to name a few.

[0061] Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and memory devices, such as semiconductor memory devices (e.g., EPROM, EEPROM, and flash memory devices), magnetic disks (e.g., internal hard disks or removable disks), magneto-optical disks, and CD-ROM and DVD-ROM disks. Processors and memory may be supplemented by or incorporated into dedicated logic circuitry.

[0062] While this specification contains numerous specific implementation details, these should not be construed as limiting the scope of any invention or the scope of the claims, but rather are primarily used to describe features of specific embodiments of a particular invention. Certain features described in the various embodiments herein may also be implemented in combination in a single embodiment. Conversely, various features described in a single embodiment may also be implemented separately in various embodiments or in any suitable sub-combination. Furthermore, while features may function in certain combinations as described above and even initially claimed in this way, one or more features from a claimed combination may be removed from that combination in some cases, and a claimed combination may refer to a sub-combination or a variation thereof.

[0063] Similarly, although the operations are depicted in a specific order in the accompanying drawings, this should not be construed as requiring these operations to be performed in the specific order shown or sequentially, or requiring all illustrated operations to be performed to achieve the desired result. In some cases, multitasking and parallel processing may be advantageous. Furthermore, the separation of various system modules and components in the above embodiments should not be construed as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

[0064] Thus, specific embodiments of the subject matter have been described. Other embodiments are within the scope of the appended claims. In some cases, the actions recited in the claims may be performed in a different order and still achieve the desired result. Furthermore, the processes depicted in the drawings are not necessarily shown in a specific order or sequence to achieve the desired result. In some implementations, multitasking and parallel processing may be advantageous.

[0065] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0066] The above are merely specific embodiments of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A PIN adaptive ultrasonic welding system based on an IGBT module, characterized in that, include: The components include an IGBT module, a welding platform, an ultrasonic welding head, a drive assembly, an impedance detection assembly, and a main controller. The welding platform is equipped with clamps to fix the IGBT module so that the welding points of the DCB board of the IGBT module correspond to the pins to be welded. The drive assembly includes an electric lead screw and a servo motor. The upper end of the electric lead screw is connected to a fixed servo motor, and the lower end of the electric lead screw is connected to the DCB plate of the ultrasonic welding head through a rigid or floating coupling. The electric lead screw is used to convert the rotational motion of the servo motor into the linear feed motion of the ultrasonic welding head in the vertical direction, so as to drive the ultrasonic welding head to move in the vertical direction. The servo motor performs corresponding rotational and displacement motions according to the adjustment commands output by the main controller. The ultrasonic welding head is connected to the lower end of the electric lead screw via a rigid or floating coupling. Driven by the linear feed motion of the electric lead screw, it moves to the position where the PIN needle contacts the welding point on the DCB board, ensuring that the contact pressure between the PIN needle and the welding point on the DCB board is within a preset optimal process pressure range. Based on the target frequency and target power output by the built-in frequency and power adjustment component, ultrasonic welding is performed on the PIN needle at the welding point on the DCB board. The target frequency and target power are obtained by the frequency and power adjustment component adjusting the ultrasonic welding head according to the ultrasonic parameter adjustment command output by the main controller. The impedance detection component is used to detect the contact impedance between the PIN pin and the ultrasonic welding head according to a preset impedance detection cycle after receiving the detection command output by the main controller, and output the detected contact impedance information to the main controller. The main controller is used to output detection commands to the impedance detection component after determining that ultrasonic welding is to be performed, receive contact impedance information transmitted by the impedance detection component, query the pre-set mapping relationship between contact impedance and adjustment strategy, obtain the adjustment strategy mapped by the contact impedance information, carry it in the adjustment command, and output it to the drive component.

2. The PIN adaptive ultrasonic welding system based on an IGBT module according to claim 1, characterized in that, A crossbeam component is also provided above the welding platform, and an electric lead screw is installed on the crossbeam component.

3. The PIN adaptive ultrasonic welding system based on an IGBT module according to claim 1, characterized in that, The ultrasonic welding head also includes multiple welding sub-heads, wherein... Each welding head is connected to the built-in frequency and power regulation components; Each welding head forms a welding head array. Each welding head in the welding head array corresponds to a welding point in the welding point array laid out on the DCB board. Each welding head corresponds to one welding point. Each soldering head receives the target frequency and target power output from the frequency and power adjustment component for that soldering head, and performs ultrasonic soldering on the PIN pins at the corresponding soldering point on the DCB board. The main controller outputs an adjustment instruction set containing ultrasonic parameter adjustment instructions for each soldering head. The frequency and power adjustment component parses the received adjustment instruction set to obtain the target frequency and target power for each soldering head.

4. The PIN adaptive ultrasonic welding system based on an IGBT module according to claim 3, characterized in that, Each of the aforementioned welding heads corresponds to an electric lead screw and a servo motor.

5. The PIN adaptive ultrasonic welding system based on an IGBT module according to claim 4, characterized in that, Each pin in the pin array corresponds to an impedance detection component.

6. The PIN adaptive ultrasonic welding system based on an IGBT module according to claim 3, characterized in that, Each welding head is equipped with an ultrasonic transducer, which converts the target power output from the frequency and power adjustment component for the welding head, containing the target frequency, into ultrasonic waves to perform ultrasonic welding on the corresponding PIN pin.

7. The PIN adaptive ultrasonic welding system based on an IGBT module according to any one of claims 1 to 6, characterized in that, The main controller is further configured to, after determining that ultrasonic welding will be performed, assign a PIN pin identifier to each PIN pin in the PIN pin array, carry the PIN pin identifier in the detection command, and output it to the impedance detection component of the corresponding PIN pin; construct a correspondence between the PIN pin identifier and the drive component based on the PIN pin array and the welding sub-head array, and output the correspondence to the drive component; and, based on the PIN pin identifier carried in the received contact impedance information, carry the PIN pin identifier in the generated adjustment command, and output the adjustment command to the drive component corresponding to the PIN pin identifier carried in the contact impedance information. The impedance detection component is also used to carry the pin identification of the detected pin in the contact impedance information.

8. The PIN adaptive ultrasonic welding system based on an IGBT module according to claim 7, characterized in that, The main controller is also used for: Based on the PIN pin identifier carried in the received contact impedance information, an impedance curve is generated for the PIN pin identifier. The impedance curve is plotted with time on the horizontal axis and the contact impedance information containing the PIN pin identifier received at each time on the vertical axis.

9. The PIN adaptive ultrasonic welding system based on an IGBT module according to any one of claims 1 to 6, characterized in that, The composition of the PIN pin is the same as or similar to that of the DCB board at the soldering point.

10. The PIN adaptive ultrasonic welding system based on an IGBT module according to any one of claims 1 to 6, characterized in that, Also includes: The vibratory plate is equipped with gears. The PIN pins to be soldered are placed in the vibratory plate. The vibration of the vibratory plate drives the PIN pins to be transmitted. The direction of the transmitted PIN pins is adjusted by the gears on the vibratory plate so that the part of the PIN pin to be soldered to the DCB board is facing the soldering point.

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