Electromagnetic interference noise in switching power converters and inherent communication / encryption
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2026-02-06
- Publication Date
- 2026-08-13
Smart Images
Figure US2026014343_13082026_PF_FP_ABST
Abstract
Description
[0001] Docket No. 050-9330 (788-297 PRO)
[0002] ELECTROMAGNETIC INTERFERENCE NOISE IN SWITCHING POWER CONVERTERS AND INHERENT COMMUNICATION / ENCRYPTION
[0003] PRIORITY
[0004] This application claims priority to U.S. Provisional Patent Application No. 63 / 755,036, filed with the U.S. Patent and Trademark Office on February 6, 2025, the entire content of which is incorporated herein by reference.
[0005] BACKGROUND
[0006] 1. Field
[0007] The disclosure relates generally to signal transmission, and more particularly, to encoding digital information in electromagnetic interference (EMI) control through a programmable gate drive for creating a signal transmission path.
[0008] 2. Description of Related Art
[0009] EMI in power electronic systems is an incidental effect caused by high-speed device switching. EMI is infrequently taught in power electronics courses and is often referred to as “black magic” because of its high complexity and nonlinearity, yet EMI filters are often necessary.
[0010] Over the past few decades, researchers have determined that primary contributors for EMI in power electronics systems include a source, such as switching power devices / modules and a converter, an impacted entity including equipment vulnerable to EM noises, and a propagation path including the physical interconnection between the source and the impacted entity. The EMI induced by the high-speed device switching can potentially interfere with system communication, sensing, and control and can create degradation and instability across system insulation.
[0011] As such, there is a need in the art for a method and apparatus that encode digital information in EMI control to improve system health monitoring and encrypted communications including cyber security.Docket No. 050-9330 (788-297 PRO)
[0012] SUMMARY
[0013] This disclosure is provided to address at least the above-mentioned problems and / or disadvantages and to provide at least the advantages described below.
[0014] Accordingly, an aspect of the disclosure is to provide an EMI noise embedded digital fingerprint concept to dissuade hackers from attempting to breach the digital fingerprint encoding mechanism.
[0015] An aspect of the disclosure is to provide a method and apparatus that overcomes shortcomings in the conventional art by enhancing EMI signature control in a power conversion system, such that interference between other systems sharing the same power supplies, signal quality degradation, and data loss or malfunction are minimized.
[0016] An aspect of the disclosure is to provide a method and apparatus by which, different from the intrinsic background EMI noises in semiconductors, the EMI noise generated by switching power devices is mitigated by controlling device switching based on the instantaneous rate of voltage change over time (dV / dt) and di / dt (, parasitic induced resonances, and a pulse-width modulation (PWM) scheme.
[0017] An aspect of the disclosure is to provide a method and apparatus for EMI control through optimal layout and parasitic control, and EMI modulation using active gating control and dV / dt control, to utilize EMI noise as an encryption and communication approach for cyber-attack hardened systems by controlling the EMI noise signature within certain EMI limits.
[0018] In accordance with an aspect of the disclosure, a method of controlling EMI signatures by a transmitter includes digitizing data into a binary code, sending the binary code to an EMI signature controller, shaping EMI emissions from the EMI signature controller into controllable EMI signatures, and transmitting the controllable EMI signatures to a receiver, wherein the EMI emissions are shaped into controllable EMI signatures by controlling on and off switching of the EMI signature controller based on an instantaneous rate of voltage change over time of the EMI emissions.Docket No. 050-9330 (788-297 PRO)
[0019] In accordance with another aspect of the disclosure, a method of controlling EMI signatures by a receiver includes receiving controllable EMI signatures from a transmitter, the EMI signatures being controllable due to an on and off switching of the transmitter related to an instantaneous rate of voltage change over time of EMI emissions, adjusting a filter bandwidth and data resolution of the EMI signatures, performing a post-processing and spectrum mapping on the EMI signatures by analyzing and refining captured data from the EMI signatures, performing a data extraction from the EMI signatures, and establishing communication between at least one power electronic converter (PEC) based on the data extracted from the EMI signatures.
[0020] BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The above and other aspects, features, and advantages of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:
[0022] FIG. 1 illustrates a conventional power conversion system with a communication path, to which the disclosure is applied;
[0023] FIG. 2 illustrates a power conversion system with an EMI encryption path, according to an embodiment;
[0024] FIG. 3 illustrates a method of controlling an EMI signature, according to an embodiment; FIG. 4 illustrates a schematic diagram of an EMI signature controller, according to an embodiment;
[0025] FIG. 5 illustrates a dual channel gate driver circuitry, according to an embodiment;
[0026] FIG. 6 illustrates a power converter for power stage slope control, according to an embodiment;
[0027] FIG. 7A illustrates a square wave, to which the disclosure is applied;
[0028] FIG. 7B illustrates a trapezoidal wave, to which the disclosure is applied;
[0029] FIG. 7C illustrates a multi-section trapezoidal wave, according to an embodiment;
[0030] FIG. 7D illustrates a spectrum of the square wave in FIG. 7A;
[0031] FIG. 7E illustrates a spectrum of the trapezoidal wave in FIG. 7E;
[0032] FIG. 7F illustrates a spectrum comparison of the waveforms in FIGs. 7A, 7B and 7C,Docket No. 050-9330 (788-297 PRO)
[0033] according to an embodiment;
[0034] FIG. 8 illustrates a time domain waveform with active gating control in EMI noise side channel encrypted communication, according to an embodiment;
[0035] FIG. 9 illustrates a real-time fast Fourier transform (FFT) spectrum in waterfall mode, according to an embodiment;
[0036] FIG. 10 illustrates a data processing method for EMI control, according to an embodiment; FIG. 11 illustrates the specifications, electrical schematic, and performance data of the EMI filter, according to an embodiment;
[0037] FIG. 12 illustrates an EMI spectra comparison using gate drive encoding, according to an embodiment;
[0038] FIG. 13 illustrates a real-time FFT EMI spectra with gate drive encoding, according to an embodiment; and
[0039] FIG. 14 illustrates a real time FFT EMI spectra with gate drive encoding, according to an embodiment.
[0040] DETAILED DESCRIPTION
[0041] Embodiments of the present disclosure will be described below with reference to the accompanying drawings. However, the embodiments of the present disclosure are not limited to the specific embodiments and should be construed as including all modifications, changes, equivalent devices and methods, and / or alternative embodiments of the present disclosure. Descriptions of well-known functions and / or configurations will be omitted for the sake of clarity and conciseness.
[0042] The terms and words used in the following description and claims are not limited to their dictionary meanings but are merely used to enable a clear and consistent understanding of the present disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of embodiments of the present disclosure is provided for illustrative purposes only and not for the purpose of limiting the present disclosure as defined by the appended claims and their equivalents.Docket No. 050-9330 (788-297 PRO)
[0043] Singular terms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. For example, reference to “a component surface” includes reference to one or more of such surfaces.
[0044] The embodiments are described herein by way of illustration only and should not be construed in any way to limit the scope of the present disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged electronic device.
[0045] As used herein, the term “substantially” indicates that the recited characteristic, parameter, or value need not be achieved exactly, but that variations such as tolerances, measurement errors, measurement accuracy limitations and other factors known to those of ordinary skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.
[0046] The expressions “have,” “may have,” “include,” and “may include” as used herein indicate the presence of corresponding features, such as numerical values, functions, operations, or parts, and do not preclude the presence of additional features. The expressions “A or B,” “at least one of A or / and B,” or “one or more of A or / and B” as used herein include all possible combinations of items enumerated with them. For example, “A or B,” “at least one of A and B,” or “at least one of A or B” indicate (1) including at least one A, (2) including at least one B, or (3) including both at least one A and at least one B.
[0047] Terms such as “first” and “second” as used herein may modify various elements regardless of an order and / or importance of the corresponding elements, and do not limit the corresponding elements. These terms may be used for the purpose of distinguishing one element from another element. For example, a first user device and a second user device may indicate different user devices regardless of the order or importance. A first element may be referred to as a second element without departing from the scope the present disclosure, and similarly, a second element may be referred to as a first element.Docket No. 050-9330 (788-297 PRO)
[0048] When a first element is “operatively or communicatively coupled with / to” or “connected to” another element, such as a second element, the first element may be directly coupled with / to the second element, and there may be an intervening element, such as a third element, between the first and second elements. To the contrary, when the first element is “directly coupled with / to” or “directly connected to” the second element, there is no intervening third element between the first and second elements.
[0049] All of the terms used herein including technical or scientific terms have the same meanings as those generally understood by an ordinary skilled person in the related art unless they are defined otherwise. The terms defined in a generally used dictionary should be interpreted as having the same or similar meanings as the contextual meanings of the relevant technology and should not be interpreted as having ideal or exaggerated meanings unless they are clearly defined herein. According to circumstances, even the terms defined in this disclosure should not be interpreted as excluding the embodiments of the present disclosure.
[0050] FIG. 1 illustrates a conventional power conversion system with a communication path, to which the disclosure is applied.
[0051] Referring to FIG. 1, the system includes a power stage 101 having a power stage controller 105, a power converter 110, power input sensors 115a, power output sensors 115b, and an EMI filter 120. The power stage controller 105 is electrically connected to a master controller 140 via a communication path 102. The EMI filter 120 is electrically connected to an energy source 135, such as the power grid, a battery source or solar panels, and the power output sensors 115b are electrically connected to a load 145, such as the power grid. Components of the system in FIG. 1 will be described in more detail in reference to FIG. 2.
[0052] FIG. 2 illustrates a power conversion system with an EMI encryption path, according to an embodiment.
[0053] Referring to FIG. 2, a power stage 201 includes a power stage controller 205, a power converter 210, power input sensors 215a, power output sensors 215b, EMI filters 220a, 220b, andDocket No. 050-9330 (788-297 PRO)
[0054] an active EMI signature controller 225. The power stage 201 is electrically connected to EMI signature extractors 230a, 230b, which are electrically connected via communication paths 203, 202, respectively, to a master controller 240. The master controller 240 may be a computer. Each EMI signature extractor 230a, 230b is connected to a power source. For example, EMI signal extractor 230a is electrically connected to energy source 235, such as the power grid, a battery source or solar panels, and EMI signal extractor 230b is electrically connected to the power grid 245. A third EMI communication path 204 is provided.
[0055] The power stage controller 205 controls the power flow between the input and output of the power converter 210. The power stage controller 205 processes the sensor data received from the power input and output sensors 215a, 215b for power regulation or circuit protection, controls the switching of power semiconductor devices such as metal oxide semiconductor field effect transistors (MOSFETs) or insulated gate bipolar transistors (IGBTs), and is vital to the power converter 210 as it impacts the efficiency and performance of the power converter 210. For example, the power stage controller 205 may be a digital signal processor (DSP) or a field programmable gate array (FPGA).
[0056] The power converter 210 is an electrical device that converts electric energy from one form to another and is classified based on the type of input and output it produces, such as an alternating current (AC)-to-AC, AC-to-direct current (DC), DC-to-AC, or DC-to-DC converter.
[0057] The assembly of the power converter 210 includes non-linear components and linear reactive components. The non-linear components are electronic switches, such as power MOSFETs, power bipolar junction transistors (BJTs), IGBTs, and thyristors, and are used to control the flow of current and voltage by switching on and off at high frequencies. The linear reactive components are capacitors, inductors, and transformers, and are used for intermediate energy storage, voltage and current filtering, voltage level changing, and isolation.
[0058] The power input and output sensors 215a, 215b connected to the power converter 210 may be current sensors, voltage sensors, power sensors, and frequency sensors which control and modulate the switching devices of the power converter 210. In doing so, the duty cycle, frequency,Docket No. 050-9330 (788-297 PRO)
[0059] and phase are adjusted for controlling the power flow direction to achieve the desired output waveform.
[0060] The power input and output sensors 215a, 215b are necessary for the power stage 201 to provide feedback to the master controller 240 or the user. This can help to regulate the output, improve the performance, protect the converter from faults, and optimize the efficiency of the system. Relatedly, this disclosure is directed to enabling a communication path for transmitting information and data collected from the power input and output sensors 215a, 215b.
[0061] The EMI filters are devices or circuits that reduce the high-frequency electromagnetic noise generated by a power converter. The EMI filters are designed to meet the requirements of regulatory agencies that limit the conducted and radiated emissions from electronic devices and ensure their immunity and transient performance. They are also designed to prevent interference between different devices or systems that share the same power or signal lines and avoid degradation of signal quality, data loss, or malfunction.
[0062] The EMI signal extractors 230a, 230b, are cost-effective devices for detecting EMI noise and provide open-source devices enabling users to access the noise measurement result.
[0063] The system as shown in FIG. 2 improves on the conventional system shown in FIG.1 by incorporating, in the power stage 201, along with the EMI filter connected to the power input sensors 215a, an EMI filter 220b connected to the power output sensors 215b, and by further incorporating the EMI signatures controller 225 in the power stage 201 and the EMI signature extractors 230a, 230b into the system. As a result, interference between other systems sharing the same power supplies, signal quality degradation, and data loss or malfunction are minimized.
[0064] FIG. 3 illustrates a method of controlling an EMI signature, according to an embodiment.
[0065] Referring to FIG. 3, the method includes a signal transmission process, a signal-to-data process, and a data transmission process which will now be described.Docket No. 050-9330 (788-297 PRO)
[0066] In the signal transmission process, the power stage di / dt and dV / dt slope is controlled in the power conversion stage 310 by switching on / off the power converter described below in reference to FIG. 6. The power conversion stage 310 is controlled by the EMI signature control 305.
[0067] In the signal -to-data process, the EMI signature is measured 315 and then processed by the digital signal processor (DSP) 320, which feeds the resulting data to an encryption signal in an expected communication rate 350 stage. If desired, some of the signal (or data) is embedded in the communication initialization 325 and is modulated in a manner similarly to amplitude modulation (AM) whereby an envelope develops on top of the AM signal for embedding the intended communication.
[0068] In the data process, the remainder of the data is decoded 330 and is then compared 335 to the original coded encryption data 340 to enable the communication path. Part of the encryption signal resulting from the coded encryption data 340 is converted to a binary signal 345 and is fed to the encryption signal in an expected communication rate 350 stage, while another part of the encryption signal 340 is fed to the stage for comparing the decoded and original data 335.
[0069] FIG. 4 illustrates a schematic diagram of an EMI signature controller, according to an embodiment. The EMI signature controller in FIG. 4 is a detailed description of the EMI signature controller 225 in FIG. 2.
[0070] Referring to FIG. 4, the EMI signature controller comprises a silicon carbide (SiC) circuit with active gate control. The active gate drive can change the gate resistors per switching cycle according to the setting, and thus to dynamically change the power device dV / dt in real-time. A dual channel gate driver provides different turn-on gate resistors Rg low 405 (5 Ohm (Q)) and Rg high 410 (20 Q) for the power switch. While swapping between these different gate resistors, the power device operates at different dV / dt during turn-on, thereby creating a varying EMI pattern.
[0071] In FIG. 4, therefore, the gate voltage from a DC-DC converter 415 is supplied to gate driver resistors Rg low 405 and Rg high 410 which are used.to vary the output 420 of the dual channelDocket No. 050-9330 (788-297 PRO)
[0072] gate drivers integrated circuit (IC) 1 and IC2. However, the disclosure is not limited thereto. For example, an analog to digital converter (ADC) can alternatively be used to control the voltage and current (or slew rate) into the gate driver.
[0073] FIG. 5 illustrates a dual channel gate driver circuitry, according to an embodiment. Referring to FIG. 5, the dual channel gate driver circuitry includes, on a flexible printed circuit board (FPCB) 510, an input 501, a filter circuit for input signals 502, a quad (4)- channel digital isolator 503, gate driver IC1 with an enable feature 504, gate driver IC2 with an enable feature 505, Rg low 506, Rg high 507, a dual channel gate driver output 508, and a DC-DC converter 509.
[0074] A conventional gate drive board is generally susceptible to a supply chain attack, as the hacker can swap out the gate drive with one having embedded malware. Adding extra encoding chips on the gate drive board to subvert this problem is easily detectable and compromised.
[0075] Disclosed is a novel approach to an encoded digital fingerprint in EMI control through a programmable gate drive. Different gate driving voltages / resistors result in a different dV / dt and instantaneous change in current over time (di / dt) of each power-device switching interval and generate different EMI noises. The gate drive voltage / driving resistor is programmed in a sequence and thus uses the differences in the EMI noise signature as the hardware fingerprint.
[0076] Similar to the previous concept, the near field emissions from power modules have the switching characteristic of the power devices in which these modules are embedded. Use of programmable gate drivers has enabled refined control of the switching speed of the power devices between various switching cycles. By combining the programmable gate drivers and monitoring the near field generated by the power modules, another layer of security is added to the power converter operation.
[0077] FIG. 6 illustrates a power converter for power stage slope control, according to an embodiment.Docket No. 050-9330 (788-297 PRO)
[0078] Referring to FIG. 6, the power converter is a DC-DC power converter and is used to achieve the testing results from the dual channel gate drivers illustrated in FIG. 5. FIG. 6 depicts performance of the power stage slope control of di / dt and dV / dt, which relates to the power conversion stage illustrated in FIG. 6. A near-field probe 615 and line impedance stabilization network (LISN) 620 are used for EMI noise measurement. Volts direct current (VDC), duty cycle, Rtoad, RGSI and RGS2 are set at the power converter as follows:
[0079] VDC = 20V
[0080] duty cycle = 25%
[0081] RLoad= 4.7 Ω
[0082] RGS1= 5 Ω
[0083] RGS2= 20 Ω
[0084] The switching device is an ONsemi NTHL080N120SC1 1200V SiC MOSFET but the disclosure is not limited thereto, as an equivalent switching device may be used.
[0085] In operation, two switches 605, 610 are configured to simultaneously turn on and off. Specifically, switch 605 is controllable by the user and turns on and off to ideally achieve a square waveform (see e.g., FIG. 7A below), but more realistically, to achieve a trapezoidal waveform (see e g., FIG. 7B below). This trapezoidal waveform has a rise time as high as about 400V / nanosecond or as low as about 5V / microsecond, and 2V / ms in SiC application. Thus, an inductor is included in the circuitry that induces a parasitic capacitance based on the distance between the neighboring windings of the inductor as well as ground in the circuitry. These aspects create a capacitance in the circuitry, albeit in a small amount such as nanofarads (nF) or picofarads (pF).
[0086] The switching waveform along with the parasitic capacitance causes the di / dt and dV / dt to excite a current propagating through all possible channels, such as the wiring in the circuitry. For example, a wire in the circuitry is a low impedance channel and the current will propagate through this channel. Current can also propagate through a side channel or leakage between the inductor and the ground, which current is referred to as the EMI.Docket No. 050-9330 (788-297 PRO)
[0087] The parasitic capacitance can be controlled by the EMI signature controller illustrated in FIG. 4. The amount of current propagating through the low impedance channel and the side channel can be controlled by varying the di / dt and dV / dt. The switching frequency controls the extent to which the current propagates in the circuitry and where the frequencies are seen in the trapezoidal waveform. In particular, the gate resistance is switched to control the waveform spectrum to achieve varying degrees of successive rising and falling wave edges for the frequency point to control the EMI and embed, in the waveform, useful information intended only for an authorized party.
[0088] FIGs. 7A-7F illustrate spectrums and waveforms in EMI generation in power electronics systems. The layout and physical configurations of the power converter and power modules form the noise propagation path for EMI noises, while the switching node is considered as the EMI noise source. The voltage and current waveforms on the switching node in the circuit are determined by the power module layout, device characteristics, gate driving circuit design and switching trajectory control. The synthesis of the noise voltage and noise propagation path impedance determines the EMI spectrum in the system.
[0089] The propagation path impedances are somewhat fixed by the power module / converter / system layout and their assembly material systems (insulation, shielding, etc.). The noise source voltage is determined by the noise time domain waveform, including its dV / dt slope, sections of transitions, high frequency ringing, and switching trajectories.
[0090] Specifically, FIG. 7A illustrates a square wave, to which the disclosure is applied, FIG. 7B illustrates a trapezoidal wave, to which the disclosure is applied, FIG. 7C illustrates a multi-section trapezoidal wave, according to an embodiment, FIG. 7D illustrates a spectrum of the square wave in FIG. 7A, FIG. 7E illustrates a spectrum of the trapezoidal wave in FIG. 7E, and FIG. 7F illustrates a spectrum comparison of the waveforms in FIGs. 7A, 7B and 7C, according to an embodiment.
[0091] Referring to FIG. 7A, and as noted above, the square wave is ideally desired when the switch 405 is controlled to turn on and off. The spectrum (or pattern) of the square wave is shownDocket No. 050-9330 (788-297 PRO)
[0092] in FIG. 7D. For example, it is unrealistic for the power to rise from 0V to 10,000V or fall from 10,000V to 0V in no time, which would yield the square wave as in FIG. 7A.
[0093] Referring to FIG. 7B and as further noted above, the trapezoidal wave is realistically achieved when the switch is controlled to turn on and off, in contrast with the square wave in FIG.
[0094] 7A. The spectrum of the trapezoidal wave in FIG. 7B is shown in FIG. 7E.
[0095] Referring to FIG. 7E, the spectrum of the trapezoidal wave relates to the di / dt and dV / dt relationship of the trapezoidal waveform in FIG. 7B, or in other words, to the slope of the waveform shown in FIG. 7B. When the switching frequency in the EMI controller increases, the trapezoidal waveform shown in FIG. 7C is produced, in which the slope is higher due to the increased current from the faster switching and is narrower in comparison to the slope of the waveform in FIG. 7B. In addition, segment 1 and segment 2 are produced in the multi-section trapezoidal wave in FIG. 7C, resulting in a slope comparison shown in FIG. 7F. As a result, the gate resistance in the EMI controller is switched to alternate between higher and lower frequency points in the spectrum, as shown in the slope comparison in FIG. 7F, in which the useful information intended only for authorized party can be safely embedded.
[0096] FIG. 8 illustrates a time domain waveform with active gating control in EMI noise side channel encrypted communication, according to an embodiment. Referring to FIG. 8, the EMI spectrum can be controlled by changing the switching waveform dV / dt by using active-gate control, and thus EMI pattern is periodically controlled in real-time. Thus, information in these changing patterns can be inserted into the EMI pattern to realize encrypted communication.
[0097] Specifically, the power converter generates a fast-chopping voltage waveform of as much as 1 million times per second. Each chopping elicits spikes 805, 810 that are noise from a power supply in the common mode (CM) channel 8 (CH6). The noise is dynamically modulated in CH4 to detect and control the internal rhythm of the waveform, such that the signal can be inserted as encrypted information 815 across a large, high frequency domain from a low to a high frequency, as shown in FIG. 9.Docket No. 050-9330 (788-297 PRO)
[0098] For accuracy of measurement purposes, the time domain waveform in FIG. 8 is not directly gauged based on each signal (or voltage) shown in each vertical line in the graph of CH6, for example. In other words, the exact amount of voltage at each line cannot be accurately determined since the exact amplitude cannot be determined. Instead, a set (or window) 820 of signals is used in the FFT measurement, thereby adapting the time domain signal to a broadband frequency domain signal, as in FIG. 9. It is noted that the window 820 of signals used in the FFT measurement is variable.
[0099] FIG. 9 illustrates a real-time FFT spectrum in waterfall mode, according to an embodiment. Referring to FIG. 9, the different shades along the time axis at the same frequency represent “1” and “0” information. This encrypted coding can be applied to either radiated or conducted EMI spectrum.
[0100] That is, the time domain signal generated in FIG. 8 is changed to a broadband frequency domain signal by performing a short term FFT on a set of voltage signals obtained at CH6 in FIG.
[0101] 8. Different spikes 905, 910, 915, 920 are shown in the different shadings in FIG. 9 based on the frequency at that point in the graph. At time 0 seconds (sec), the spectrum spike represents the FFT performed for one time period. With these spike-initiated patterns, the distance between different spikes 905, 910, 915, 920 and their frequency resolution are used to serve as 1’s and 0’s to encrypt the information. It is noted that additional spikes are shown in FIG. 9 but are not described, for conciseness. The signal in the broadband frequency domain is undetectable since it is immersed in noise.
[0102] FIG. 10 illustrates a data processing method for EMI control, according to an embodiment. Referring to FIG. 10, the transmitter may be any power electronic converter (PEC) with active switching transistors. Steps 1010-1025 are performed by the PEC transmitter and steps 1035 are performed by a PEC receiver, which may also be a computer.
[0103] In step 1010, at the transmitter end, data to be sent is procured, and may be any data that is to be communicated between the transmitter and receiver.Docket No. 050-9330 (788-297 PRO)
[0104] In step 1015, data is digitized into a binary code by converting information into a digital format represented by a series of 0s and 1s for processing or transmitting and combining with a protocol definition.
[0105] In step 1020, a binary code is passed (sent) to an EMI signature controller (i.e., a power electronic converter (PEC)), which is controlled to generate different EMI signature operations, such as a voltage and current slew rate, switching frequencies, and noise peak amplitude.
[0106] In step 1025, the EMI emissions of PECs are managed and shaped into a controllable EMI signature.
[0107] In step 1030, coupling paths between the transmitter and a receiver are connected for conducting the EMI emission and signatures between the transmitter and receiver, such as including a power line, ground, and free air.
[0108] In step 1035, at the receiver end, EMI signature capture is performed by any probe, antenna, or fixture designed to collect EM waves current and voltage signatures, such as a near-field probe, current transformer, band-pass filter, H-loop antenna, or E-field antenna.
[0109] In step 1040, pickup filter bandwidth / data resolution is adjusted by fine-tuning the filter’s frequency range and the granularity of the data measurement. As a result, signal clarity and detail for specific analysis requirements is optimized.
[0110] In step 1045, EMI signature post-processing and spectrum mapping are performed by software tools that analyze and refine captured EMI data to identify patterns and extract binary coded data from the patterns, including but not limited to EMI spectrum mapping and EMI signature point correlation.
[0111] In step 1050, data extraction is performed by decoding the extracted binary code and extracting the transmitted data.Docket No. 050-9330 (788-297 PRO)
[0112] In step 1055, communication is established by data exchange between PECs using a predefined protocol and EMI signatures based on the extracted data in step 1050 to enable interaction and information sharing.
[0113] FIG. 11 illustrates the specifications, electrical schematic, and performance data of the EMI filter, according to an embodiment.
[0114] Referring to FIG. 11, the specification for the EMI filter testing includes a high potential (Hipot) rating of 2250 VDC line to ground, 1450 VDC line to line, and an operating ambient temperature range of negative 10 degrees Celsius (-10°C) to +55°C. The maximum operating current calculation is shown for when the ambient temperature exceeds +55°C. The performance data is shown based on a common mode per line to ground and a differential mode per line to line and is measured in a closed 50 Ω system.
[0115] FIG. 12 illustrates an EMI spectra comparison using gate drive encoding, according to an embodiment. FIG. 13 illustrates a real-time FFT EMI spectra with gate drive encoding, according to an embodiment. FIG. 14 illustrates a real time FFT EMI spectra with gate drive encoding, according to an embodiment. For conciseness, FIGs. 12, 13 and 14 will be described together in the following description.
[0116] The disclosure provides an advanced power module with a near field embedded identification signature. Module power devices switch at high dV / dt and di / dt, which generates different types of EMI noises. With a settled module layout, the module radiated EMI emission pattern at different frequencies is identical. If the module is swapped with a different design, although two modules can have the same housing and appearance, their radiated EMI signatures remain different. This feature is used in FIGs. 12, 13 and 14 as an embedded fingerprint for a secure and trustworthy module design.
[0117] Also disclosed herein are the results of work on near-field EMI modeling for different power layouts. This work has enabled the design of different gallium nitride (GaN) module near-field layouts with amplitude and frequency control.Docket No. 050-9330 (788-297 PRO)
[0118] To achieve the results shown in FIGs. 12, 13 and 14, the near field is monitored by a near field antenna that is embedded as part of the gate driver PCB. The output of this antenna is fed to an auxiliary FPGA running real-time FFTs to monitor the near field around 1 to 4 megahertz (MHz). As shown in FIG. 14, the change in the near field is only visible in real-time FFT and not during emissions testing.
[0119] As shown in FIG. 12. 13 and 14, a pattern for the switching speed is created, and the auxiliary FPGA monitors these patterns. For example, consider a medium voltage (MV) SiC power module, such as 6-10 kilovolts, with switching speeds of 100 nanoseconds (ns) and with a switching frequency of 50 kilohertz (kHz). For every 100 cycles, if the switching speed is lowered to 250 ns for 5 switching cycles without any change in the switching or fundamental frequency, this change is reflected directly in the near field generated by the power module. The real time FFT for this scenario is shown in FIGs.12, 13 and 14.
[0120] This time-domain noise encryption method does not alter the overall EMI spectrum for qualification testing, while only real-time FFT detection with a known bandwidth can capture this digital fingerprint.
[0121] As described above, by controlling the switching power device dV / dt, one can modulate the EMI signal to encode information into EMI noises and use the encoded information for data exchange and communication. This communication does not require specific physical communication interconnections, while all the information is immersed in the EMI spectrum. This method provides additional security in the communication system and reduces cost due to minimal hardware requirements.
[0122] One or more blocks of message flow diagrams disclosed herein may be performed by computer program instructions. Because these computer program instructions may be mounted in a processor of a general purpose computer, special purpose computer, or other programmable data processing equipment, the instructions performed by a processor of a computer or other programmable data processing equipment generate a means that performs functions described inDocket No. 050-9330 (788-297 PRO)
[0123] the message flow diagram block(s). Since these computer program instructions may be stored in a computer usable or computer readable memory that may direct a computer or other programmable data processing equipment to implement a function in a particular manner, the instructions stored in the computer usable or computer readable memory may produce a production article containing instructions for performing the function described in the message flow diagram block(s). Because the computer program instructions may be mounted on a computer or other programmable data processing equipment, a series of operation steps are performed on the computer or other programmable data processing equipment to generate a computer-executable process; thus, instructions for performing the computer or other programmable data processing equipment may provide steps for performing functions described in the message flow diagram block(s).
[0124] Each block may represent a portion of a module, a segment, or a code including one or more executable instructions for executing a specified logical function(s). In some alternative implementations, functions recited in the blocks may occur out of order. For example, two blocks illustrated one after another may in fact be performed substantially simultaneously, or the blocks may be sometimes performed in the reverse order according to the corresponding function.
[0125] In this case, the term unit may indicate software or hardware components such as the FPGA or an application specific integrated circuit (ASIC). However, a unit is not limited to software or hardware and may be constituted to reside in an addressable storage medium or may be constituted to reproduce one or more processors.
[0126] Methods disclosed herein may be implemented in the form of hardware, software, or a combination of hardware and software.
[0127] When implemented in software, a computer readable storage medium storing one or more programs (software modules) may be provided. One or more programs stored in the computer readable storage medium are configured for execution by one or more processors and may include instructions for causing the particular device, such as the computer, to execute methods described herein.Docket No. 050-9330 (788-297 PRO)
[0128] Such programs (software modules, software) may be stored in a random access memory, a non-volatile memory including a flash memory, a read only memory (ROM), an electrically erasable programmable ROM (EEPROM), a magnetic disc storage device, a compact disc-ROM (CD-ROM), digital versatile discs (DVDs), another form of optical storage device, or a magnetic cassette. Alternatively, the programs may be stored in a memory composed of a combination of some or all thereof.
[0129] Components included in the disclosure have been expressed in the singular or the plural according to the presented specific embodiments. However, the singular or plural expression is appropriately selected for a presented situation for convenience of description, and the disclosure is not limited to the singular or plural components, and even if a component is represented in the plural, it may be composed of the singular, or even if a component is represented in the singular, it may be composed of the plural.
[0130] While the disclosure has been described with reference to various embodiments, various changes may be made without departing from the spirit and the scope of the present disclosure, which is defined, not by the detailed description and embodiments, but by the appended claims and their equivalents.Traditional Power Conversion System with Communication Path Power Stage
[0131] i
[0132] Communication path
[0133] \ Master Controller | ■ Power Stage |
[0134] I Controller
[0135] \ (Computer) |
[0136] I (DSP / FPGA) | |
[0137] I
[0138] Sensor Control Sensor i
[0139] Signals Signals Signals1
[0140] 2 > s i
[0141] I. j. i
[0142] I
[0143] Energy Source I EM!i— ~ Power pQWerPower H p Load / (Batery / Solar Power Line(trrtput ~ i, Output | |
[0144] Panels / Grid) Filter Power Grid i
[0145]
[0146] “sm- T i
[0147] I iPower Conversion System with EMI Encryption Path
[0148] Power Stage
[0149]
[0150] MI Communication Path Sensor Signais s
[0151] s Communication path s Master Controller Power Stage Active EMI s Controlier Control Signatures Signais (Computer) Controller (DSP / FPGA) s s Gate Dnye Communication path Sensors i Signais Q'cjnalgi.
[0152] EMI EMI Energy Source Power Power Power EMI EMI Load / (Battery / Solar Power Line Signature Cable Bundle:Signature Intput Output Power Gr Filter Converter Filter i: Sensors < Panels / Grid) Sensors Extractor Extractor
[0153]
[0154] i i £
[0155]
[0156] Power Stage Controller (DSP / FPGA)
[0157] • A power stage controller is part of a power electronic converter stage (Power stage).
[0158] • It controls the power flow between the input and output of the converter.
[0159] • It process the sensor data for power regulation or circuit protection.
[0160] • It is responsible for controlling the switching of power semiconductor devices such as MOSFETs or IGBTs.
[0161] • The power stage controller is an essential part of a power electronic converter as it determines the efficiency and performance of the converter.Power Converter
[0162] • A power converter is an electrical device that converts electric energy from one form to another.
[0163] • They can be classified based on the type of input and output they produce, such as AC-to-AC, AC-to-DC, DC-to-AC, or DC-to-DC converters.
[0164] • A power converter assembly contains non-linear components and linear reactive components.
[0165] • Non-linear components are mainly electronic switches, such as power MOSFETs, power BJTs, IGBTs, thyristors, etc. They are used to control the flow of current and voltage by switching on and off at high frequencies.
[0166] • Linear reactive components are capacitors, inductors, and transformers. They are used for intermediate energy storage, voltage and current filtering, voltage level changing, and isolation.
[0167]
[0168] Power Input / Output Sensors
[0169] • Input and output sensors in a power converter are usually Current sensors, Voltage sensors, Power sensors, and Frequency sensors.
[0170] • It can also control and modulate the switching devices of the power converter. This can help to adjust the duty cycle, frequency, and phase for controlling the power flow direction to achieve the desired output waveform.
[0171] • They are needed for the power stage to provide feedback to the controller or the user.
[0172] This can help to regulate the output, improve the performance, protect the converter from faults, and optimize the efficiency. This invention is targeting to create a communication path for transmitting information / data collected from those sensors.EMI Filter
[0173] • EMI filters are devices or circuits that reduce the high-frequency electromagnetic noise generated by a power converter.
[0174] • They are designed to meet the requirements of regulatory agencies, such as FCC, FAA, etc., that limit the radiated and conducted and radiated emissions from electronic devices and ensure their immunity and transient performance.
[0175] • They are designed to prevent interference between different devices or systems that share the same power or signal lines and avoid degradation of signal quality, data loss, or malfunction.
[0176]
[0177] Experimental Validation
[0178] Radiated and conducted EMI with cable, and EMI filter
[0179]
[0180] DC link cable: 4 AWG battery wire EMI filter: TE connectivity DA Series
[0181] Signal generation and extraction
[0182] Using DSP to send encryption signal in binary to the system Encryption signal extraction with a cost-effective method
[0183]
[0184] Proposed Validation Setup
[0185]
[0186] EMI Filter for Testing (DA Series)
[0187] Specifications Performance Data
[0188] Hipot rating (one minute): Minimum Insertion Loss
[0189] Line to Ground: 2250 VDC Measured in closed 50 Ohm system
[0190] Line to Line: 1450 VDC
[0191] Common Mode / Asymmetrical (Line to Ground) Rated Voltage (max): 125 VDC
[0192] Current Frequency -MHz
[0193]
[0194] Rated Current: 3 to 15A Rating .05 .1 .15 .5 1 3 5 10 30 100 200 Operating Ambient Temperature Range 3A - 6 9 11 26 41 48 55 46 22 16 (at rated current lr): -10”C to -f-BS^C ( 6A 2 4 6 18 30 37 42 48 42 - - in an ambient temperature (Ta) higher than +55°C | 1 A
[0195]
[0196] - 1 4 8 17 25 30 36 38 21 11 the maximum operating current (lo) is calculated as
[0197] 15A - - - 3 5 13 19 25 2 10 14^ follows: io= Ir√(85-Ta) / 45
[0198] Differential Mode / Symmetrical (Line to Line) Electrical Schematic Current Frequency - MHz
[0199] Rating .05 .1 .15 .5 1 3 5 10 30 100 200 3A - 4 7 16 18 37 47 50 43 31 36 6A * 4 7 19 21 27 40 53 41 - - 10A 2 4 6 17 22 23 32 48 38 30 26 15A - - 2 17 19 29 33 37 37 31 28
[0200]
[0201] [1]" ENG_CS_1654001_CORCOM_PRODUCT_GUIDE_0611.pdf’, https: / / www.te.com
[0202]
[0203] Encryption Date Extraction
[0204]
[0205] • A cost-effective method for detecting EMI noise
[0206] • An open-source device that allows users access to the noise measurement result • Develop a communication protocol for communication initiation
[0207]
[0208] Data Processing Flowchart
[0209]
[0210] Receiver Transmitter
[0211] (Power Converter / (Power Converter)
[0212] : Power line with EMI Signatures Central Computer) < -: Data communication
[0213] Power line connection with EMI Signature
[0214]
[0215]
[0216] Application configuration Daisy Chain configuration:
[0217] Converter communicate with each other
[0218] Common bus configuration: Converter reports to central computer
[0219] Common bus configuration: Converter communicate with each other Power Source / Grid
[0220]
[0221] Power line with EMI Signatures —: communication path directionMethod for Detecting EMI noise
[0222] • |0 Spectrum Analyzer
[0223] • Level of noise at different frequencies in a frequency range
[0224] • Capable of detecting both intentional and unintentional interference
[0225] • H Oscilloscope
[0226] • Measure signal amplitude versus time domain
[0227] • Capable of identifying interference on power lines or other high-voltage signals
[0228] • Broadband RF Field Meter
[0229] • Measures the amount of electromagnetic interference in a specific area
[0230] • Radio Receiver
[0231] • Radio Communications Analyzer
[0232]
[0233] Title: EMI noise in Switching Power Converters and Its Inherent Communication / Encryption Feature
[0234] Abstract:
[0235] Switching power electronic converters are supporting electric energy conversion in almost every aspect of our daily life, from cellphone chargers, computers, and home appliances, to electric transportations. The reliability and resiliency of these converters are critical, yet the converter hardware is vulnerable to cyber-attacks. In this proposed project, the PI will investigate the "side effects" of switching power converters and study the relationship these "second-order characteristics "with specific converter designs. Through this study, the PI plans to generate a new encryption method using the Electro-Magnetic Interference noise signal to encode digital fingerprint for power converters, and further look into the possibility of using this encrypted noise signal for communications in a power converter system. This proposed idea can significantly enhance the security feature at the cyber-physics layer and further improve the reliability of existing power converter systems.
[0236] Project Description
[0237] 1. Overview and Background:
[0238] Electromagnetic interference (EMI) issues in pcnver electronic systems, is a “side-effect” caused by high-speed device switching. EMI matters are not commonly taught as part of power electronics courses and are sometimes even referred to as “black magic” because of its high complexity and nonlinearity, yet EMI filters are a “necessary evil”. Over the past decades of research, researchers has identified that the key contributors for EMI in power electronics systems includes (1) the source, usually it is the switching power devices / modules and the converter, (2) the victim, it is the equipment that vulnerable to EM noises, (2) propagation path, it is the physical interconnections between the source and the victim.
[0239] 2. Proposed Research
[0240] Basic principle In this research, the team would like to study the EMI signatures from the noise source aspect Different from the intrinsic background EMI noises in semiconductors, the EMI noise generated by switching power devices is determined by (a) device switching dV / dt & dt / dt, (b)parasitic induced resonances, and (c) PWM modulation scheme. By controlling these three factors, the EMI noises should be controlled. In this proposed research, the team would like to have a systematic study the relationship between the controllable variables and their influences to the EMI emission pattern in power electronics systems. Specific focus will be given to (I) EMI control through optimal layout and parasitic control, (2) EMI modulation using active gating control and dV / dt control Other than simply apply noise reduction control, the team would like to utilize the EMI noise as an encry ption and communication approach for cyber-attack hardened systems by controlling the EMI noise signature within a certain EMI limits.
[0241] The team would like to propose an “EMI Noise Embedded Digital Fingerprint” concept without obvious encoding chips or extra hardware, so that hackers will not breach the digital
[0242] 1fingerprint encoding mechanism easily. This Embedded Digital Fingerprint concept includes three parts.
[0243] (1) Advanced Power Module with near field embedded ID signature. Module power devices switches at high dV / dt and di / dt, which generates different types of EMI noises. With a settled module layout, the module radiated emi emission pattern at different frequencies are identical. If the module is swapped with a different design, even two modules can have the same housing and appearance, their radiated EMI signatures are still different. We can use this feature as an embedded fingerprint for module design of trust.
[0244] UA team has also generated a series work on nearfield EMI modeling for different power layouts This work has enabled the design of a specific nearfield patent in different layouts with control of its amplitude and frequency, as shown in Fig.4-6. The team will design and characterize the XHP module layout, and use its specific patent as a module level ID to determine the fidelity of power modules.
[0245] (2) Programmable Gate Drive for time-varying digital fingerprint encoded in EMI noise.
[0246] Gate drive board is another weak link for supply chain attack, as the hacker can swap out the gate drive with embedded malware in it However, adding extra encoding chips on gate drive board is too obvious and easy to be compromised.
[0247] The team would like to use a new way to encoded digital fingerprint in E I control through programmable gate drive. Different gate driving voltages / resistors result in different dV / dt and di / dt of each power-device switching interval, and generate different EMI noises. We can program the gate drive voltage / driving resistor in a sequence, and thus use the differences in EMI noise signature as the hardware “fingerprint”.
[0248] Similar to the previous concept, the near field emissions from power modules has the switching characteristic of the power devices embedded in it. Use of programmable gate drivers has enabled refined control of the switching speed of the power devices from one switching cycle to the other. By combining the programmable gate drivers and monitoring the near-field generated by the power modules, another layer of security could be added to the power converter operation. The near field will be monitored by a near-field antenna that would be embedded as part of the gate driver PCB The output of this antenna would be fed to an auxiliary FPGA running real-time FFT to monitor the near-field around 1 to 4 MHz. The change in the near-field will be only visible in real-time FFT and not during conventional emissions testing. A pattern for the switching speed could be created, and the auxiliary FPGA would monitor these patterns. For example, consider an MV SiC power module with switching speeds of 100 ns and with a switching frequency of 50 kHz. For every 100 cycles, if the switching speed is lowered to 250 ns for 5 switching cycles without any change in the switching or fundamental frequency. This change would be reflected directly in the near field generated by the power module. The real time FFT for this scenario is shown in Fig.7-
[0249] 2Fig.9 This time-domain noise encryption method will not change the overall EMI spectrum for qualification testing, while only real-time FFT detection with known bandwidth can capture this digital fingerprint.
[0250] (3) EMI signature covered communication. According to previous analysis, by controlling the switching power device dV / dt, one can modulate the EMI signal, this feature provides a potential avenue to encode information into EMI noises and use it for data exchange and communication This communication will not require specific physical communication interconnections, while all the information are immersed in EMI spectrum. This potential method can provide extra security to the communication and also reduce the communication system cost due to reduced hardware requirement. The team will study the possibility and process to use this method for communication, determine its bandwidth limitations and effective range for communication.
[0251] Fig.l. Proposed SiC module and its gate drive Fig.3. Proposed SiC MV PEBB
[0252] 15. W 45 Ml 75 X vis (mm) Fig.5. Calculated nearfield patent of a Fig.4. Measured nearfield patent of a GaN GaN Module (from Luo’s lab) Fig.6. GaN module layout used in
[0253]
[0254] Module nearfield testing
[0255] 3Fig.7. EMI spectra comparisons using Fig.8. EMI spectra W / O Fig.9. realtime FFT EMI spectra with
[0256]
[0257] gate drive encoding gate drive encoding gate drive encoding The PI has been working on EMI modeling and mitigation since 2007(15-20], and he is currently under support by NSF on his EMI research. His team has built up a unique EMI research capability covering conducted EMI and radiated EMI in power electronics systems. Fig.10 shows the nearfield EMI mapping system in Luo’s lab which is designed and tested by his team.
[0258]
[0259] Automated Radiated EMI measurement setup Fig.10. EMI scanning system at Pi’s lab
[0260] 4
Claims
Docket No. 050-9330 (788-297 PRO)WHAT IS CLAIMED IS:
1. A method of controlling electromagnetic interference (EMI) signatures by a transmitter, the method comprising:digitizing data into a binary code;sending the binary code to an EMI signature controller;shaping EMI emissions from the EMI signature controller into controllable EMI signatures; andtransmitting the controllable EMI signatures to a receiver,wherein the EMI emissions are shaped into controllable EMI signatures by controlling on and off switching of the EMI signature controller based on an instantaneous rate of voltage change over time of the EMI emissions.
2. The method of claim 1,wherein the binary code sent to the EMI signature controller is configured to cause one or more EMI signature operations to be generated.
3. The method of claim 2,wherein the one or more EMI signature operations include voltage and current slew rate, switching frequencies, and noise peak amplitude.
4. The method of claim 1,wherein the controllable EMI signatures are transmitted to the receiver through a coupling path including at least one of a power line, ground, and air.
5. A method of controlling electromagnetic interference (EMI) signatures by a receiver, the method comprising:receiving controllable EMI signatures from a transmitter, the EMI signatures being controllable due to an on and off switching of the transmitter related to an instantaneous rate of voltage change over time of EMI emissions;adjusting a filter bandwidth and data resolution of the EMI signatures;Docket No. 050-9330 (788-297 PRO)performing a post-processing and spectrum mapping on the EMI signatures by analyzing and refining captured data from the EMI signatures;performing a data extraction from the EMI signatures; andestablishing communication between at least one power electronic converter (PEC) based on the data extracted from the EMI signatures.
6. The method of claim 5. wherein the controllable EMI signatures are received by at least one of a near field probe, current transformer, band-pass filter or antenna of the receiver.
7. The method of claim 5, wherein the filter bandwidth and data resolution are adjusted by fine-tuning a filter frequency range and a granularity of the data captured from the EMI signatures.
8. The method of claim 7,wherein the captured data is analyzed and refined to identify patterns and extract binary coded data from the patterns.
9. The method of clam 5,wherein the communication is established by a data exchange between the receiver and the at least one PEC using a predefined protocol and EMI signatures based on the extracted data.