CN114778921B - Power module switching voltage measurement method based on fringe electric field - Google Patents
Power module switching voltage measurement method based on fringe electric field Download PDFInfo
- Publication number
- CN114778921B CN114778921B CN202210436462.2A CN202210436462A CN114778921B CN 114778921 B CN114778921 B CN 114778921B CN 202210436462 A CN202210436462 A CN 202210436462A CN 114778921 B CN114778921 B CN 114778921B
- Authority
- CN
- China
- Prior art keywords
- electrode
- power module
- fringe field
- voltage
- sensor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 230000005684 electric field Effects 0.000 title claims abstract description 45
- 238000000691 measurement method Methods 0.000 title claims abstract description 9
- 230000006698 induction Effects 0.000 claims abstract description 55
- 238000012545 processing Methods 0.000 claims abstract description 50
- 238000000034 method Methods 0.000 claims abstract description 24
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 38
- 229910052802 copper Inorganic materials 0.000 claims description 38
- 239000010949 copper Substances 0.000 claims description 38
- 239000000758 substrate Substances 0.000 claims description 38
- 239000000919 ceramic Substances 0.000 claims description 21
- 238000005259 measurement Methods 0.000 claims description 16
- 230000010354 integration Effects 0.000 claims description 15
- 239000000463 material Substances 0.000 claims description 7
- 238000013461 design Methods 0.000 claims description 6
- 229910000679 solder Inorganic materials 0.000 claims description 6
- FRWYFWZENXDZMU-UHFFFAOYSA-N 2-iodoquinoline Chemical compound C1=CC=CC2=NC(I)=CC=C21 FRWYFWZENXDZMU-UHFFFAOYSA-N 0.000 claims description 4
- LTPBRCUWZOMYOC-UHFFFAOYSA-N beryllium oxide Inorganic materials O=[Be] LTPBRCUWZOMYOC-UHFFFAOYSA-N 0.000 claims description 4
- 238000001514 detection method Methods 0.000 claims description 3
- 238000004806 packaging method and process Methods 0.000 claims description 3
- 239000004020 conductor Substances 0.000 claims description 2
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 claims description 2
- 239000012811 non-conductive material Substances 0.000 claims description 2
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 2
- 230000001419 dependent effect Effects 0.000 claims 1
- 239000003990 capacitor Substances 0.000 description 20
- 239000000523 sample Substances 0.000 description 12
- 230000000694 effects Effects 0.000 description 7
- 238000010586 diagram Methods 0.000 description 6
- 238000012546 transfer Methods 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- 230000036039 immunity Effects 0.000 description 2
- 230000003071 parasitic effect Effects 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 230000017525 heat dissipation Effects 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 230000005405 multipole Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/0084—Arrangements for measuring currents or voltages or for indicating presence or sign thereof measuring voltage only
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
- G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
- G01D5/24—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying capacitance
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Testing Of Individual Semiconductor Devices (AREA)
Abstract
The invention relates to a power module switch voltage measurement method based on a fringe field, which comprises a fringe field sensor and a signal processing circuit, wherein the fringe field sensor is integrated in a power module, the signal processing circuit is arranged outside the power module, the fringe field sensor comprises an electrode layer, the electrode layer comprises a driving electrode, an induction electrode and a shielding electrode, the driving electrode is connected with a voltage signal of a device to be measured in the power module, the induction electrode can form a fringe field with the driving electrode to induce an electrode of the measured voltage signal, and the shielding electrode is used for shielding an electrode of the power module except for an induction area, which is interfered by the electric field signal; the signal processing circuit is connected with the induction electrode in the fringe field sensor, and the fringe field sensor is used for sensing the voltage signal to be measured. The method solves the problem that the traditional voltage measurement method is inaccurate in measuring the switching characteristics of the device while improving the power density and the reliability of the module.
Description
Technical Field
The invention belongs to the field of voltage sensing, and particularly relates to a power module switching voltage measurement method based on a fringe electric field.
Background
With the increasing demand for high power density and high integration of power electronic systems, research and development of integrated sensors is being pushed to a new level. Currently, integrated current sensors have been typically studied, and integrated voltage sensors have not been systematically studied. The existing voltage sensor mainly aims at measuring discrete power devices and lacks a measuring method which can be integrated in a power module.
The common voltage sensor comprises a voltage probe and a circuit type voltage sensor, wherein the oscilloscope voltage probe is widely applied to measurement of device switching voltage information, and mainly comprises a passive probe, an active differential probe and an optical isolation probe, although the existing probes can meet different measurement requirements according to different advantages of the existing probes, the existing probes are externally connected to two ends of a tested circuit, and are required to be directly and electrically connected with the tested circuit, parasitic parameters are introduced into the tested circuit, so that measurement signals are inaccurate, and meanwhile, the integrated voltage sensor is not suitable for being used due to a complex connection mode and a large volume. While the circuit-type voltage sensor at the element level or the converter level has certain advantages in the field of integration, the number of passive devices (the number of the passive devices is tens of) is large, so that the stability and the reliability of the sensor are more challenged, and great difficulty exists in the process of integration development. How to meet the requirement of high power density and accurately measure the switching voltage is the content of the integrated voltage sensor to be further researched.
Disclosure of Invention
Aiming at the related problem of integrating a voltage sensor into a power module, the invention provides a switching voltage measurement method suitable for power module integration and based on a fringe field principle, which aims at improving the power density and reliability of the module and solving the problem that the traditional voltage measurement method is inaccurate in measuring the switching characteristics of devices.
In order to achieve the above purpose, the technical scheme of the invention is as follows:
The invention provides a fringe field based power module switch voltage measurement method, which comprises a fringe field sensor and a signal processing circuit, wherein the fringe field sensor is integrated in a power module, the signal processing circuit is arranged outside the power module and is connected with an induction electrode in the fringe field sensor, the fringe field sensor is used for sensing a voltage signal to be measured, and the signal processing circuit is used for reconstructing the signal sensed by the sensor so as to realize accurate measurement of the voltage signal.
The fringe field sensor comprises an electrode layer and a sensor substrate, wherein the electrode layer comprises a driving electrode, a sensing electrode and a shielding electrode, the driving electrode refers to an electrode which is connected with an inner chip of the power module and has a measured voltage signal, the sensing electrode refers to an electrode which forms a fringe electric field with the driving electrode to sense the measured voltage signal, and the shielding electrode refers to an electrode which is used for shielding electric field signal interference in the power module except for a sensing area (an electric field area formed between the driving electrode and the sensing electrode). The driving electrodes and the induction electrodes are alternately arranged on the same plane, the placement rules are different according to the electrode shapes, for example, when the driving electrodes and the induction electrodes are in interdigital, the fingers of the driving electrodes and the induction electrodes are mutually inserted, if the driving electrodes and the induction electrodes are in concentric rings, the driving electrodes and the induction electrodes are alternately arranged in the same plane in a circle of driving electrodes and a circle of induction electrodes, and the driving electrodes are connected with voltage signals of devices to be measured in the power module; the shielding electrode is positioned outside the area where the driving electrode and the sensing electrode are positioned and surrounds the driving electrode and the sensing electrode. The sensor substrate is arranged below the plane where the three electrodes are arranged, and the sensor substrate is required to completely bear the three electrodes, but the size of the power module is considered, so that the sensor substrate is not required to be excessively large. The back of the sensor substrate is provided with a layer of backboard which is the same as the sensor substrate in size but different in thickness and material, the sensor substrate is made of non-conductive material, the backboard is made of conductive material, and the thickness of the backboard is usually thinner than that of the sensor substrate, and the backboard is grounded during measurement.
When the device in the power module is switched on and off, the drive electrode is provided with a measured voltage with a certain amplitude and frequency, a fringe electric field is formed between the induction electrode and the drive electrode, and then an induction capacitance is generated between the two electrodes, at this time, the induction voltage is arranged on the induction electrode, and then the induction electrode is connected with an external signal processing circuit, so that the obtained induction voltage can be transmitted to the input end of the signal processing circuit. In the signal processing circuit part, the resistor R 1 and the capacitor C 1 firstly carry out attenuation reduction processing on the acquired signals, and then the voltage signals obtained by attenuation reduction are further reconstructed through the active integration circuit. And finally, outputting a voltage signal at the output end of the signal processing circuit to finish the whole voltage detection process.
The application relates to a fringe electric field sensor, which belongs to a capacitance sensor, and utilizes a sensing capacitance generated between a driving electrode and a sensing electrode, when a voltage exists on the driving electrode, an electric field is generated between the driving electrode and the sensing electrode, and then the sensing capacitance is formed, if the voltage on the driving electrode changes, the electric field between the two electrodes and the sensing capacitance change, so that the sensing voltage generated on the sensing electrode changes, and the positions of the driving electrode, the sensing electrode and a shielding electrode are fixed in the whole process. In summary, the working principle of the application is as follows: the method comprises the steps of driving voltage change, fringe electric field change between a driving electrode and a sensing electrode, sensing capacitance change between the two electrodes and sensing voltage change on the sensing electrode.
Compared with the prior art, the invention has the beneficial effects that:
1. The invention provides a voltage sensing scheme capable of being integrated in a power module based on a fringe electric field principle, and the voltage sensor is integrated in the power module to measure voltage. During measurement, the measured voltage with certain amplitude and frequency is applied to the driving electrode of the sensor, and a fringe electric field is generated between the measured voltage and the sensing electrode, so that a sensing capacitor is formed between the two electrodes. The voltage signal to be measured can be reconstructed by connecting the sensing electrode with an external signal processing circuit. The invention solves the problem that the existing voltage sensor cannot be integrated, provides possibility for improving the reliability and integration degree of the power module, and provides a new thought for researching the integrated voltage sensor.
2. The invention uses the induction capacitance generated by the electric field between the two electrodes to measure the voltage, so the interference problem of the electric field signal to the edge electric field except the induction area is not ignored, the backboard is grounded to shield the interference from the lower part of the edge sensor, and shielding measures are adopted on the plane of the induction electrode, the plane of the backboard and the signal outgoing line, so that shielding in multiple directions is realized, and the invention has certain immunity. First, the driving electrode and the shielding electrode outside the sensing electrode can shield the interference of the electric field signal outside the sensing area in the module. Secondly, the backboard on the back of the sensor substrate is grounded during measurement and can be also regarded as a shielding electrode, so that the interference of the electric field below the fringe field sensor can be shielded. And finally, the wire pair induction electrode with the shielding effect is selected to be connected with an external signal processing circuit, so that the external influence on signals in the transmission process is reduced, and the accuracy of the measured switching voltage information is further ensured.
3. The fringe field sensor provided by the invention has the characteristics of simple structure and small volume, overcomes the problem that the conventional measuring mode cannot be integrated due to large volume and complex connecting mode, is easy to integrate in different application scenes, and is used for measuring the voltage signal by utilizing the fringe field principle, and no direct electrical connection is arranged between the sensor and a tested line, so that the problem of serious invasiveness caused by the introduction of parasitic parameters in the conventional measuring mode is solved, and the measuring accuracy is improved.
Drawings
Fig. 1 is a graph of the effect of a voltage probe on the switching voltage waveform of a device.
Fig. 2 is a schematic diagram of a parallel plate capacitor.
Fig. 3 is a schematic diagram of an interdigital voltage sensor.
Fig. 4 is a schematic structural diagram of a power module according to an embodiment.
Fig. 5 is a schematic diagram of a fringe field sensor.
Fig. 6 is a schematic diagram of a signal processing circuit.
In the figure, a power module substrate 1, a lower copper layer 2, a ceramic layer 3, an upper copper layer 4, a chip 5, a driving electrode 6, an induction electrode 7, a shielding electrode 8 and a signal processing circuit 9 are arranged.
Detailed Description
The present application is further explained below with reference to examples and drawings, but is not limited thereto.
At present, the measurement of the switching voltage of the power electronic device is mainly completed through an oscilloscope probe, the oscilloscope probe is required to be directly and electrically connected with a tested circuit in the measurement mode, extra capacitance and inductance are introduced into the tested circuit, a certain invasive problem is generated, the measured signal is delayed, meanwhile, the oscillation phenomenon of the signal is aggravated, the accuracy of a measurement result is influenced, and the voltage probe influences the switching voltage waveform of the device as shown in fig. 1.
Fig. 2 is a schematic diagram of a parallel plate capacitor, which is the most common and popular capacitor, and is widely used in various situations, but has edge effects, and for an ideal parallel plate capacitance sensor, if the edge effects are ignored, the plate area, plate spacing and dielectric constant are known to obtain the capacitance value between the plates. When considering the fringe effect of the electric field, the length and width of the polar plate are also required to be considered so as to obtain an accurate capacitance value. The application utilizes the fringe effect that the driving electrode and the induction electrode of the fringe electric field sensor are positioned on the same plane, when the measured voltage exists on the driving electrode, a fringe electric field is formed between the two electrodes, the electric field lines are led to the induction electrode by the driving electrode, are elliptic and diffuse outwards, meanwhile, an induction capacitance is formed between the driving electrode and the induction electrode, when the measured voltage changes, the electric field between the two electrodes changes, and the induction capacitance value also changes. The electrode shape may be interdigital, concentric ring, rectangular, etc., and the interdigital electrode structure is preferred in this embodiment to specifically describe the fringe field sensor. As shown in fig. 3, the fingers of the driving electrode and the sensing electrode of the interdigital voltage sensor are mutually spliced, and the two electrodes can be monopolar or be designed as multipole pairs.
The voltage sensing scheme provided by the invention is used for measuring the switching voltage information in the power module based on the fringe electric field, and comprises a fringe electric field sensor and a signal processing circuit, wherein the fringe electric field sensor is integrated in the power module, and voltage signals are measured in a mode of applying voltage to a driving electrode and inducing an electric field to an induction electrode. The signal processing circuit is used for reconstructing the detected voltage signal sensed by the sensing electrode and is arranged outside the power module, and the signal processing circuit is connected with the sensing electrode.
The fringe field sensor can be integrated in various power modules in different modes, and can be used for measuring voltage inside the power modules according to different modes integrated in actual application scenes. The embodiment preferably designs the fringe field sensor by relying on a SiC MOSFET power module structure and realizes an integrated scheme. As shown in fig. 4, the bottom of the SiC MOSFET power module is a power module substrate 1 made of copper material; the copper-clad ceramic plate (DBC) is welded on the power module substrate 1 through solder, the copper-clad ceramic plate (DBC) is of a sandwich structure, a ceramic layer (an electric insulating material plate) is arranged in the middle of the copper-clad ceramic plate, copper layers are respectively arranged on the upper side and the lower side of the ceramic layer 3 and are respectively marked as an upper copper layer 4 and a lower copper layer 2, the lower copper layer 2 is connected with the power module substrate 1 through solder, and the upper copper layer 4 is connected with a SiC MOSFET chip of the SiC MOSFET power module through solder.
Etching a driving electrode and an induction electrode with expected design sizes on an upper copper layer of a copper-clad ceramic plate, wherein a ceramic layer in the copper-clad ceramic plate is a sensor substrate of a fringe electric field sensor, the materials of the sensor substrate can be aluminum oxide, beryllium oxide, aluminum nitride and the like, dielectric constants are respectively different from 6 to 10, and beryllium oxide is preferably used as a ceramic plate material, and the dielectric constant is between 6 and 7; the thickness of the sensor substrate ranges from 0.25mm to 1.2mm, and can be 0.25mm, 0.32mm, 0.38mm, 0.5mm, 0.63mm, 1mm and the like, and the sensor substrate is preferably a ceramic plate with the thickness of 1 mm;
The electrode shape of the fringe field sensor is interdigital, concentric ring, rectangular, etc., and the interdigital electrode structure is preferable in this embodiment to specifically describe the fringe field sensor. The fingers of the driving electrode and the sensing electrode are mutually spliced, the shielding electrode is positioned at the outer side of the area where the driving electrode and the sensing electrode are positioned, and the driving electrode and the sensing electrode are surrounded. The number of pole pairs of the driving electrode and the sensing electrode can be 1-8 pairs limited by the size of the power module, and the blank area except the driving electrode and the sensing electrode in the power module is based on the fact that shielding electrodes with corresponding shapes can be just placed, and the preferred number of pole pairs is 6 in the embodiment.
According to the design purpose of the invention, the wavelength lambda of the fringe electric field sensor (the distance between adjacent nearest single electrode central lines) can be in the range of 1-6mm, and the wavelength lambda=3 mm is preferable in the embodiment. Considering that the power module can generate an air breakdown problem when working in a high-voltage state, and simultaneously comprehensively considering the size of the SiC MOSFET power module, in the embodiment, the width of a single electrode in the driving electrode and the sensing electrode is preferably 1mm, and the length of the single electrode in the driving electrode and the sensing electrode is preferably 20mm.
In this embodiment, the electrode of the fringe field sensor is an upper copper layer 4, the back plate is a lower copper layer 2, and both are surface copper layers of the DBC, and the thicknesses of the upper and lower copper layers are mainly 0.1mm, 0.2mm, 0.25mm, 0.3mm, 0.4mm, 0.5mm, etc., so that the thickness difference between the upper and lower copper layers cannot exceed 50um in order to ensure good heat dissipation and insulation pressure resistance of the DBC, and the same thickness is preferably adopted, so that the thicknesses of the upper and lower copper layers of the sensor are preferably 0.1mm, i.e., the thicknesses of the electrode and the back plate are preferably 0.1mm.
The power modules in the application can be SiC MOSFET power modules, siC JFET power modules, IGBT power modules and the like, and the chips in the corresponding power modules are SiC MOSFET chips, siC JFET chips, IGBT chips and the like. If the fringe field sensor is integrated in the SiC MOSFET power module, the drain electrode of the SiC MOSFET chip is required to be connected with the driving electrode, and the source electrode of the SiC MOSFET chip is required to be connected with the shielding electrode; if the fringe field sensor is integrated in the SiC JFET power module, the drain electrode of the SiC JFET chip is required to be connected with the driving electrode, and the source electrode of the SiC JFET chip is required to be connected with the shielding electrode; if the fringe field sensor is integrated in the IGBT power module, the collector of the IGBT chip needs to be connected to the drive electrode and the emitter of the IGBT chip to the shield electrode. In addition, the power module can be provided with a plurality of identical power device chips, and one chip is arbitrarily selected to be connected with the fringe field sensor in the mode.
The sensing of the switch voltage information can be achieved in the following manner, as shown in fig. 5: the driving electrode is connected with the drain electrode of the SiC MOSFET chip, the connection can be realized through a bonding wire, the driving electrode can also be directly etched on a copper layer on a copper-clad ceramic plate (DBC) connected with the drain electrode of the SiC MOSFET, the sensing electrode is connected with an external signal processing circuit 9, and a sensed measured voltage signal is transmitted to the outside of the module for reconstruction. The shielding electrode is arranged at the outermost sides of the driving electrode and the sensing electrode and is connected with the source electrode of the SiC MOSFET chip so as to shield the interference of electric field signals except the sensing area and realize accurate measurement of switch voltage information in the module. When the SiC MOSFET device is switched, a driving voltage (namely a detected voltage V D) with a certain frequency and amplitude is generated at a driving electrode connected with a drain electrode, a fringe electric field is formed between the driving electrode and the sensing electrode, so that a sensing capacitor C s is generated between the driving electrode and the sensing electrode, the sensing electrode can be connected with an external signal processing circuit through integrating a radio frequency connector in the power module, and the sensing voltage V S is led out of the power module. In order to avoid interference of external signals on the measurement result in the transmission process, wires with shielding effect are used for connection, and accuracy of measured switching voltage information of the device is guaranteed.
The fringe field sensor can be designed without depending on the existing structure of the power module, can be designed independently according to the composition and basic principle of an electrode layer and a sensor substrate, and then is integrated into the power module, and the specific method can be as follows: an insulating layer is placed on an upper copper layer in the power module, then the designed complete fringe electric field sensor is fixedly placed on the insulating layer, and a driving electrode, an induction electrode, a shielding electrode and a back plate of the fringe electric field sensor are respectively connected with corresponding positions through bonding wires according to the same rules as those of the fringe electric field sensor designed by means of the existing structure of the power module, so that the purpose of sensing switch voltage information in the module can be achieved. The designed complete fringe electric field sensor is characterized in that a driving electrode, an induction electrode and a shielding electrode are positioned on the same plane, the driving electrode and the induction electrode are alternately arranged, the shielding electrode is positioned at the periphery of the driving electrode and the induction electrode, the driving electrode, the induction electrode and the shielding electrode are completely borne on a sensor substrate, and a layer of back plate is arranged on the back surface of the sensor substrate; the driving electrode is connected with one end of the chip in the power module to be tested, which is provided with a tested voltage signal, the induction electrode is connected with the signal processing circuit 9, the shielding electrode and the signal processing circuit are simultaneously connected with the chip grounding end of the power module, and the backboard is grounded. The invention can also directly arrange the sensor substrate on the upper copper layer in the power module without independently arranging the backboard and the insulating layer of the sensor, and at the moment, the upper copper layer can serve as the backboard of the fringe field sensor, so that the integral thickness of the fringe field sensor which needs to be integrated is reduced, and the sensor can be integrated in a more limited power module packaging shell. In addition, different pole pairs, electrode forms and whether to use the existing layer structure of the power module can be set according to the size of the residual space in the power module packaging shell.
The connection between the sensing electrode and the signal processing circuit can be realized in various modes such as a radio frequency connector, a wire, a power module terminal and the like. The radio frequency connector structure is divided into three types of patch type, direct insertion type and hybrid type according to the connection mode of the guide pin, the shell and the PCB, and in order to facilitate integration in the module, the embodiment is preferably connected through the patch type radio frequency connector. The specific connection method comprises the following steps: the folded plate part of the patch type radio frequency connector is connected with the induction electrode, the straight plate part is connected with the shielding electrode, one input of the signal processing circuit is connected with the central guide pin, signals of the induction electrode are obtained, and the other input of the signal processing circuit is connected with the cylindrical part.
The signal processing circuit is mainly used for reconstructing the voltage signal measured by the sensor, and can select different circuits according to different application scenes and requirements, such as an active integration circuit, a passive integration circuit, a filter circuit, a voltage follower circuit and the like. The signal processing circuit in this embodiment includes a voltage reduction circuit and an active integration circuit, where the voltage reduction circuit mainly reduces the signal induced by the sensor, and includes a capacitor C 1 and a resistor R 1. The sensing electrode is connected to the voltage reduction circuit through a radio frequency connector integrated in the power module, namely, the sensing capacitor C s is connected with one end of the capacitor C 1 and one end of the resistor R 1, and the other ends of the capacitor C 1 and the resistor R 1 are grounded, as shown in fig. 6. The active integration circuit is used for further processing voltage signals and comprises an operational amplifier, a feedback capacitor C f, a feedback resistor R f and a grounding resistor R 2, wherein the non-inverting input end of the operational amplifier is connected with the capacitor C 1 and the non-grounding end of the resistor R 1, the inverting input end is connected with the grounding resistor R 2, the feedback capacitor C f and one end of the feedback resistor R f, the other ends of the feedback capacitor C f and the feedback resistor R f are connected with the output end of the operational amplifier, the reconstructed output voltage is V O.
The voltage reduction circuit comprises a resistor R 1 and a capacitor C 1, one end of the voltage reduction circuit is connected with a sensing capacitor C s, the other end of the voltage reduction circuit is connected with signal ground, and the voltage reduction circuit can carry out attenuation reduction treatment on a voltage signal generated by a sensing electrode and then transmit the treated voltage signal to the active integration circuit. The transfer function H 1(s) of the induced capacitance C s generated between the driving electrode and the sensing electrode of the fringe field sensor and the voltage reduction circuit portion is:
S in the above equation is a special operator in the frequency domain calculation.
The active integrating circuit consists of an operational amplifier, a feedback capacitor C f, a feedback resistor R f and a grounding resistor R 2, wherein the operational amplifier
The non-inverting input end is connected with the output voltage signal of the voltage reduction circuit, the inverting input end is connected with one end of the grounding resistor R 2, the feedback capacitor C f and the feedback resistor R f, and the output end is connected with the other ends of the feedback capacitor C f and the feedback resistor R f. The transfer function H 2(s) of the active integrating circuit portion is:
In order to obtain accurate measurement results and ensure stability under high frequency, the operational amplifier in the invention is preferably of a type with high input impedance, low input capacitance and high bandwidth, the feedback resistance R f is preferably more than 500kΩ, the feedback capacitance C f is preferably of an nF level, and the grounding resistance R 2 is preferably of a few kΩ level. When R f is much larger than R 2, the transfer function of the active integration circuit can be reduced to the following:
Therefore, the reconstruction of the voltage signal measured by the fringe field sensor integrated in the power module is realized. Other circuit designs and parameter selections can also be implemented to process signals measured by the fringe field sensor.
In addition to processing the induced voltage signal obtained by the edge electric field sensor by using an analog signal processing circuit composed of a resistor, a capacitor, an operational amplifier, and the like, a digital signal processing method may be selected to realize the processing of the voltage signal. The main steps of digital signal processing are: first, an analog signal can be converted into a digital signal by an analog-to-digital converter (a/D converter); then, performing transform domain analysis, digital filtering and the like by a Digital Signal Processor (DSP); finally, the processed digital signal is restored to an analog signal by a digital-to-analog converter (D/a converter), but this step is not essential and the digital signal processing may be performed by the first two steps only.
The integrated voltage sensor designed based on the fringe field principle (namely the fringe field sensor integrated in the power module) has the typical characteristics of high design flexibility, high measurement accuracy and strong immunity, is suitable for being integrated in various power modules, can realize on-line detection of switch voltage in the modules, provides possibility for improving the reliability and integration degree of the power modules, and provides a new idea for researching the integrated voltage sensor.
The invention is applicable to the prior art where it is not described.
Claims (12)
1. The method is characterized by comprising a fringe field sensor and a signal processing circuit, wherein the fringe field sensor is integrated in a power module, the signal processing circuit is arranged outside the power module, the fringe field sensor comprises an electrode layer, the electrode layer comprises a driving electrode, an induction electrode and a shielding electrode, the driving electrode is connected with a voltage signal of a device to be measured in the power module, the induction electrode can form a fringe field with the driving electrode to induce an electrode of the measured voltage signal, and the shielding electrode is used for shielding an electrode of the power module except for electric field signal interference in the induction area;
The signal processing circuit is connected with the induction electrode in the fringe field sensor, the fringe field sensor is used for sensing the voltage signal to be measured, and the signal processing circuit is used for reconstructing the signal sensed by the sensor so as to realize accurate measurement of the voltage signal;
the fringe field sensor is not dependent on the existing structure of the power module, is designed independently according to an electrode layer and a sensor substrate, and is integrated into the power module, and the specific method is as follows: placing an insulating layer on an upper copper layer in the power module, then fixedly placing the designed complete fringe field sensor on the insulating layer, and respectively connecting a driving electrode, an induction electrode, a shielding electrode and a backboard of the fringe field sensor correspondingly through bonding wires; the designed complete fringe electric field sensor is characterized in that a driving electrode, an induction electrode and a shielding electrode are positioned on the same plane, the driving electrode and the induction electrode are alternately arranged, the shielding electrode is positioned at the periphery of the driving electrode and the induction electrode, the driving electrode, the induction electrode and the shielding electrode are completely borne on a sensor substrate, and a layer of back plate is arranged on the back surface of the sensor substrate; the driving electrode is connected with one end of the chip in the power module to be tested, which is provided with a tested voltage signal, the sensing electrode is connected with the signal processing circuit, the shielding electrode and the signal processing circuit are simultaneously connected with the chip grounding end of the power module, the backboard is grounded, the backboard is arranged on the insulating layer, and the fringe electric field sensor is integrated and packaged in the existing packaging shell of the power module;
or the back plate and the insulating layer of the sensor are not independently arranged, the sensor substrate is directly arranged on the upper copper layer in the power module, and the upper copper layer can serve as the back plate of the fringe electric field sensor.
2. The method for measuring the switching voltage of the power module based on the fringe field according to claim 1, wherein the driving electrode and the sensing electrode are alternately arranged on the same plane, the shielding electrode is positioned on the outer side of the area where the driving electrode and the sensing electrode are positioned, the driving electrode and the sensing electrode are surrounded, the three electrodes are completely carried on the sensor substrate, a back plate is arranged on the other side of the sensor substrate, the back plate is made of a conductive material, and the sensor substrate is made of a non-conductive material.
3. The fringe field based power module switching voltage measuring method of claim 1 wherein the drive electrode and the sense electrode are interdigitated electrodes, fingers of the drive electrode and the sense electrode being interdigitated; the driving electrodes and the induction electrodes are concentric ring electrodes and are alternately arranged in the same plane in a mode of one circle of driving electrodes and one circle of induction electrodes; the back plate and the sensor substrate are the same in size, but different in thickness and different in material, the thickness of the back plate is thinner than that of the sensor substrate, and the back plate is grounded during measurement; the pole pair numbers of the driving electrode and the sensing electrode are 4-8 pairs, and the blank area except the driving electrode and the sensing electrode in the power module is subject to the condition that shielding electrodes with corresponding shapes can be just placed.
4. The method for measuring switching voltage of power module based on fringe field as defined in claim 1, wherein when the device in the power module is switched, a measured voltage having amplitude and frequency is generated on the driving electrode, fringe field is formed between the sensing electrode and the driving electrode, and further a sensing capacitance is generated between the sensing electrode and the driving electrode, and then the sensing voltage is generated on the sensing electrode, and then the sensing electrode is connected with an external signal processing circuit to transmit the obtained sensing voltage to the input end of the signal processing circuit; in the signal processing circuit part, firstly carrying out attenuation and reduction processing on the acquired signals, then further reconstructing voltage signals obtained by attenuation and reduction through an active integration circuit, and finally outputting the voltage signals at the output end of the signal processing circuit to finish the whole voltage detection process; if the voltage on the driving electrode changes, the electric field and the induction capacitance between the two electrodes change, so that the induction voltage generated on the induction electrode changes, and the positions of the driving electrode, the induction electrode and the shielding electrode are fixed in the whole process.
5. The fringe field based power module switching voltage measuring method of claim 1 wherein the signal processing circuit is coupled to the sensing electrode using a coaxial cable with a shielding layer.
6. The fringe field based power module switching voltage measurement method of claim 1 wherein the fringe field sensor is integrated in various power modules in different ways, the power modules being SiC MOSFET power modules, siC JFET power modules, or IGBT power modules;
When the fringe electric field sensor is integrated in the SiC MOSFET power module, the bottom of the SiC MOSFET power module is a power module substrate made of copper materials; the copper-clad ceramic plate is welded on the power module substrate through solder, the copper-clad ceramic plate is of a sandwich structure, the middle of the copper-clad ceramic plate is a ceramic layer, copper layers are arranged on the upper side and the lower side of the ceramic layer, the upper copper layer and the lower copper layer are respectively marked as an upper copper layer and a lower copper layer, the lower copper layer is connected with the power module substrate through solder, and the upper copper layer is connected with a SiC MOSFET chip of the SiC MOSFET power module through solder;
The driving electrode of the fringe electric field sensor is connected with the drain electrode of the SiC MOSFET chip, the driving electrode is directly etched on the upper copper layer of the copper-clad ceramic plate connected with the drain electrode of the SiC MOSFET, and the sensing electrode is connected with an external signal processing circuit; the shielding electrode is arranged at the outermost sides of the driving electrode and the sensing electrode and is connected with the source electrode of the SiC MOSFET chip; the shielding electrode, the driving electrode and the induction electrode are all positioned on the upper copper layer, the middle ceramic layer is the sensor substrate of the fringe electric field sensor, and the lower copper layer is the backboard;
When a plurality of same power device chips are arranged in the power module, one chip is arbitrarily selected to be connected with the fringe field sensor in the mode.
7. The method for measuring the switching voltage of the power module based on the fringe field according to claim 6, wherein the driving electrode and the sensing electrode with expected design dimensions are etched on the upper copper layer of the copper-clad ceramic plate, the sensor substrate is made of aluminum oxide, beryllium oxide or aluminum nitride, and the dielectric constant is between 6 and 10; the thickness range of the sensor substrate is 0.25-1.2mm; the thickness of the upper copper layer and the lower copper layer is 0.1-0.5mm, and the thickness difference of the upper copper layer and the lower copper layer cannot exceed 50um.
8. The method for measuring the switching voltage of the power module based on the fringe field according to claim 6, wherein beryllium oxide is used as a material of the sensor substrate, and the dielectric constant is between 6 and 7; the sensor substrate is a ceramic plate 1mm thick.
9. The method for measuring the switching voltage of the power module based on the fringe field according to claim 1, wherein the electrode shape of the fringe field sensor is interdigital, concentric ring or rectangular, the wavelength lambda of the fringe field sensor is 1-6mm, and the width of a single electrode in the driving electrode and the sensing electrode is 1mm and the length is 20mm.
10. The fringe field based power module switching voltage measuring method of claim 9 wherein the fringe field sensor has a wavelength λ = 3mm.
11. The method for measuring the switching voltage of the power module based on the fringe field according to claim 1, wherein the connection between the sensing electrode and the signal processing circuit is realized by a radio frequency connector, a wire or a terminal of the power module.
12. The method for measuring the switching voltage of the power module based on the fringe field according to claim 11, wherein the connection between the sensing electrode and the signal processing circuit is performed by a patch type radio frequency connector, and the specific connection method is as follows: the folded plate part of the patch type radio frequency connector is connected with the induction electrode, the straight plate part is connected with the shielding electrode, one input of the signal processing circuit is connected with the central guide pin of the patch type radio frequency connector to obtain a signal of the induction electrode, and the other input of the signal processing circuit is connected with the cylindrical part of the patch type radio frequency connector.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210436462.2A CN114778921B (en) | 2022-04-25 | 2022-04-25 | Power module switching voltage measurement method based on fringe electric field |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210436462.2A CN114778921B (en) | 2022-04-25 | 2022-04-25 | Power module switching voltage measurement method based on fringe electric field |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114778921A CN114778921A (en) | 2022-07-22 |
| CN114778921B true CN114778921B (en) | 2024-06-18 |
Family
ID=82432282
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210436462.2A Active CN114778921B (en) | 2022-04-25 | 2022-04-25 | Power module switching voltage measurement method based on fringe electric field |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114778921B (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103808769A (en) * | 2012-11-06 | 2014-05-21 | 姜韫英 | Fringing electric field sensor measurement system |
| CN105158582A (en) * | 2015-09-29 | 2015-12-16 | 北京工业大学 | Variable-interval interdigitated adjacent capacitive sensor |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000171491A (en) * | 1998-12-03 | 2000-06-23 | Mitsubishi Electric Corp | Power semiconductor module |
| CN104198906B (en) * | 2014-08-27 | 2017-06-13 | 华北电力大学 | A kind of device and method for IGBT dynamic characteristic measurings |
| CN105424066A (en) * | 2014-09-17 | 2016-03-23 | 陶建臣 | EZdsp-based fringing electric field sensor measuring system |
| CN109917179B (en) * | 2019-03-20 | 2021-03-19 | 中国科学院上海微系统与信息技术研究所 | Current detection system and current detection method based on parasitic inductance of power device |
| CN111313874A (en) * | 2020-03-18 | 2020-06-19 | 上海海事大学 | Current detection device for SiC MOSFET and short-circuit protection method |
| CN114076860B (en) * | 2020-08-19 | 2023-02-28 | 华中科技大学 | Voltage detection device for half-bridge type power module |
| CN215678531U (en) * | 2021-08-26 | 2022-01-28 | 鞍山鸿维电力设备有限公司 | Instantaneous coupling voltage detection device of integrated variable frequency speed control system |
| CN114295952B (en) * | 2021-12-30 | 2023-08-11 | 河北工业大学 | Non-contact voltage measurement method for dynamic voltage measurement of power device |
-
2022
- 2022-04-25 CN CN202210436462.2A patent/CN114778921B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103808769A (en) * | 2012-11-06 | 2014-05-21 | 姜韫英 | Fringing electric field sensor measurement system |
| CN105158582A (en) * | 2015-09-29 | 2015-12-16 | 北京工业大学 | Variable-interval interdigitated adjacent capacitive sensor |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114778921A (en) | 2022-07-22 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5151032B2 (en) | Magnetic field probe device and magnetic field probe element | |
| CN101706537B (en) | PEA space charge test device capable of testing conductive current | |
| CN112526221B (en) | Electromagnetic field composite probe and detection system | |
| JP5513379B2 (en) | System for transmitting electrical pulses and capacitive decoupling device for the same | |
| US7839151B2 (en) | Solid electrolytic capacitor inspection device and inspection method | |
| CN114295952B (en) | Non-contact voltage measurement method for dynamic voltage measurement of power device | |
| CN114778921B (en) | Power module switching voltage measurement method based on fringe electric field | |
| US6239587B1 (en) | Probe for monitoring radio frequency voltage and current | |
| CN104833865A (en) | Flat sample space charge distribution measuring apparatus capable of preventing electromagnetic interference and method thereof | |
| CN101187675A (en) | Probe capable of transmitting high frequency signal | |
| CN201707425U (en) | Detection device for integrated circuit testing | |
| JP2010122139A (en) | High-frequency probe card | |
| CN215678531U (en) | Instantaneous coupling voltage detection device of integrated variable frequency speed control system | |
| JPH09199237A (en) | Shielded cable with connector | |
| CN202486187U (en) | Passive RC integrator | |
| CN115097298B (en) | Power device switching voltage measurement method based on fringe electric field coupling | |
| CN217605971U (en) | Capacitance testing device and system | |
| JP5338084B2 (en) | Capacitor inspection device and inspection method using the same | |
| CN1108512C (en) | Underwater displacement measuring method and equipment | |
| CN218331827U (en) | Testing device for self-heating effect of semiconductor device | |
| CN118012297B (en) | Capacitance detection calibration circuit and nonlinear calibration method for capacitance array | |
| CN115119391B (en) | Anti-interference high-frequency signal transmission circuit board capable of reducing stray capacitance based on low dielectric constant of gas | |
| CN111812392B (en) | Overvoltage detection circuit | |
| JP5361023B2 (en) | Method for measuring high-frequency signal transmission characteristics of wiring board and wiring board used therefor | |
| JP5356051B2 (en) | Non-contact continuity test method and apparatus |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |