Electronic controller for rapid defrosting and automated defogging in vehicles

Abstract

Disclosed are methods and systems for vehicle surface defrosting, defogging, and defect notification. In some embodiments, sensors and control of electrical signals are used for defrosting, defogging, or preventing condensation. In some embodiments, vehicle surface defects are detected and a notification is generated and communicated for vehicle surface repair or replacement.

Description

[0001] ELECTRONIC CONTROLLER FOR RAPID DEFROSTING AND AUTOMATED DEFOGGING IN VEHICLES

[0002] FIELD

[0003] The present disclosure relates to methods and systems for defrosting and defogging surfaces of vehicles, such as those of Electric Vehicles (EVs).

[0004] BACKGROUND

[0005] Transparent windshields for various vehicles, such as cars, rail vehicles including trains, streetcars, and locomotives, snowmobiles, airplanes, helicopters and sea vessels, are deiced or defrosted using available on-board power. Typically, defrosting is accomplished by blowing air heated by the vehicle's engine onto the windshield. In gas engine vehicles, deicing / defrosting takes a considerable amount of time since the engine is initially cold upon startup. In EVs, a considerable amount of energy from the battery is used to produce the heat to defrost or deice the windshield.

[0006] A windshield deicing system was previously introduced using pulse electro thermal deicing (PETD) as disclosed in US Pat Nos. 8,921,739 and 6,870,139. Such a system provides a high density of heating power (W / m2) which allows for rapid and energy efficient deicing or defrosting. It should be noted that throughout the present disclosure use of the term “defrosting” and “deicing” will be used interchangeably to generally refer to removing frozen water from a surface.

[0007] Electric vehicles are growing at a very rapid rate and are expected to reach 50% of global sales in the early 2030s. Previous defrosting / defogging methods were developed for gas engines. However, EVs present different challenges for managing power input to the controller and controller outputs to the windshield.

[0008] In EVs, the same methods for air defrost and air defog have carried over to EVs from gas vehicles. However, the source of the power for defrost and defog in an EV often is generated from the EV's high-voltage battery, the same source of power for motor power. So any energy diverted from the battery to defrost and defog reduces the driving range. One study of actual driving range in EV fleets by Geotab found that at -20°C, actual driving range dropped by 41% compared to stated range due to cabin heating, which includes defrost and defog.

[0009] To defrost a low-e windshield or glass that has transparent conductive metal coatings inside of the glass lamination, a voltage is applied to this conductive layer. In order to minimize the heat used to remove frost, ice and fog from a vehicle's glass surface, high power levels of typically 3 kW or more, are applied to this metal layer. This is the minimal power level to completely defrost and defog the windshield by itself, without air defrost or defog and down to temperatures of -40°C.

[0010] The metal layers used in glass typically have resistance levels of 1-15 ohms. To reach these power levels high-voltage levels (typically 250V to 900V, nominal) directly from the high-voltage battery can be provided to a controller that controls the power to the windshield and optimizes the power level to provide the minimal amount, or more, of heat to melt the interfacial layer of ice, thus making it easy to remove mechanically with gravity, wipers, or another method. This low energy method is very efficient because it does not attempt to melt the entire mass of ice. Due to the variation in operating voltages of about + / - 25% based on the state of charge (SOC) for the battery, a step-down transformer may be needed to provide optimal power to the glass surface.

[0011] Windshield defrosting / defogging systems using pulse-electro thermal deicing (PETD)provide a high density of heating power (W / m2), which allows for rapid and energyefficient defrosting. Rapid heating ensures that the thin, or boundary, layer of ice (e. g., between 1 pm and 1 mm) at the ice / windshield interface is heated to the ice melting point. In one variation, windshield heaters are continuous film metal-oxide transparent coatings made of indium-tin-oxide (ITO), Zinc-oxide, tin-oxide or any other electrically conductive, transparent, film made of a single metal oxide or a composite of several metal oxides. In another variation, windshield heaters are thin optically transparent metal films made of silver, aluminum, gold or the like, or of an electrically conductive and optically transparent polymer material.

[0012] In automotive, commercial vehicle and other markets, high-voltage (HV) systems are defined as those with voltage levels above 60V. At high voltages, the OEMs and industry standards bodies have additional safety requirements and standards. In some cases, these requirements reduce the risk of human exposure to these high voltages. Additionally, costs for high-voltage components are generally more expensive since the sales volumes are lower. Accordingly, systems that operate at lower ranges, e.g., below 60V, have lower design requirements and lower costs.

[0013] BRIEF SUMMARY

[0014] According to a first aspect, there is provided a system for defogging and defrosting a vehicle surface including: a vehicle surface adapted to receive discontinuous electrical signals for application to said vehicle surface; at least one DC bus; and a power controller for providing the electrical signals to the vehicle surface, the power controller coupled to a first DC bus of the at least one DC bus via an input EMI filter, coupled to the vehicle surface via an output filter, and including a voltage converter controlled by a microcontroller for modulating voltage and current levels for the electrical signals, and internal signal sensors for monitoring the provision of electrical signals to the vehicle surface.

[0015] In some embodiments, the electrical signals provided to the vehicle surface are low- voltage high-current signals, and the output filter of the power controller includes a low-voltage high-current output filter.

[0016] In some embodiments, the voltage converter of the power controller includes galvanic isolation coupled between the EMI filter and the low-voltage high-current output filter.

[0017] In some embodiments, the first DC bus includes a high-voltage DC bus, and the voltage converter includes a synchronous rectifier coupled between the galvanic isolation and the low- voltage high-current output filter configured for low-voltage high-current operation, and a full bridge MOSFET coupled between the input EMI filter and the galvanic isolation.

[0018] In some embodiments, the power controller further includes a first isolated gate driver coupled between the microcontroller and the full bridge MOSFET and a second isolated gate driver coupled between the microcontroller and the synchronous rectifier, the first and second isolated gate drivers for use by the microcontroller in controlling a pulsing of the electrical signals.

[0019] In some embodiments, the first DC bus includes a high-voltage DC bus, in which the at least one DC bus includes a low-voltage DC bus, in which the power controller is coupled to the low-voltage DC bus, and in which the voltage converter includes an output full bridge MOSFET configured for low-voltage high-current operation and coupled between the galvanic isolation and the low-voltage high-current output filter, and an input full bridge MOSFET coupled between the input EMI filter and the galvanic isolation.

[0020] In some embodiments, the power controller further includes a first isolated gate driver coupled between the microcontroller and the input full bridge MOSFET and a second isolated gate driver coupled between the microcontroller and the output full bridge MOSFET, the first and second isolated gate drivers for use by the microcontroller in controlling a pulsing of the electrical signals.

[0021] In some embodiments, the power controller further includes a further output full bridge MOSFET coupled between the galvanic isolation and the low-voltage DC bus, and an isolated gate driver coupled between the microcontroller and the further output full bridge MOSFET, whereby the power controller performs DC / DC conversion between the high-voltage DC bus and the low-voltage DC bus.

[0022] In some embodiments, the first DC bus includes a low-voltage DC bus, and in which the voltage converter includes, coupled between the EMI filter and the low-voltage high-current output filter, a multi-phase converter without galvanic isolation for adjusting voltage levels of the electrical signals.

[0023] In some embodiments, the power controller further includes an isolated gate driver coupled between the microcontroller and the multi-phase converter, the isolated gate driver for use by the microcontroller in controlling a pulsing of the electrical signals.

[0024] In some embodiments, the power controller further includes vehicle surface sensors for generating vehicle surface data for use by the microcontroller in said modulating voltage and current levels for the electrical signals.

[0025] In some embodiments, the discontinuous electrical signals include pulse electro thermal defrosting (PETD) signals.

[0026] In some embodiments, the vehicle surface comprises a windshield.

[0027] According to another aspect, there is provided a method of preventing condensation on a vehicle surface of a vehicle, the method including: gathering data from sensors of the vehicle; determining a dew point from the data; and controlling a temperature of the vehicle surface to remain above the dewpoint with discontinuous electrical signals provided to the vehicle surface. In some embodiments, the sensors of the vehicle include at least one of a cabin temperature sensor, a cabin relative humidity sensor, an outside temperature sensor, and a vehicle surface temperature sensor.

[0028] Some embodiments further provide for: determining parameters for driving the electrical signals from the data measured from the sensors.

[0029] In some embodiments, data from the sensors is sampled intermittently at an adjustable time period determined with use of the data measured from the sensors.

[0030] According to a further aspect, there is provided a method of automatic notification of a defect in a vehicle surface of a vehicle, the method including: detecting the defect in the vehicle surface; sending a signal to the vehicle Controller Area Network (CAN) bus with a Diagnostic Troubleshooting Code (DTC) error message; and communicating a notification of the DTC error thereby notifying a defect in the vehicle surface for repair or replacement.

[0031] In some embodiments, communicating the notification includes sending an error message to a driver of the vehicle via one or more of local vehicle display and electronic notification to electronic device of the driver.

[0032] In some embodiments, communicating the notification includes sending an error message to an Original Equipment Manufacturer (OEM) by the vehicle.

[0033] Some embodiments further provide for sending the communicated notification to a service provider for facilitating repair or replacement of the vehicle surface.

[0034] BRIEF DESCRIPTION OF THE DRAWINGS

[0035] To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the figure number in which that element is first introduced. In order to better understand various exemplary embodiments, reference is made to the accompanying drawings.

[0036] FIG. 1 illustrates a known defrost / defog system.

[0037] FIG. 2 illustrates a defrost / defog system including a Type I Power Controller according to an embodiment.

[0038] FIG. 3 illustrates a Type I Power Controller according to an embodiment. FIG. 4 illustrates a defrost / defog system including a Type II Power Controller according to an embodiment.

[0039] FIG. 5 illustrates a Type II Power Controller according to an embodiment.

[0040] FIG. 6 illustrates a defrost / defog system including a Type III Power Controller according to an embodiment.

[0041] FIG. 7 illustrates a Type III Power Controller according to an embodiment.

[0042] FIG. 8 illustrates a method of automated defogging according to an embodiment.

[0043] FIG. 9 illustrates a method of defect detection reporting according to an embodiment.

[0044] DETAILED DESCRIPTION

[0045] Safe, simple and cost efficient, low energy surface defrosting and defogging systems and methods are disclosed. The systems utilize step-up converters, step-down converters, DC / DC converters to provide power levels high enough to defrost a glass surface in less than 1.5 minutes. Some of the disclosed systems include sensors for exterior temperature and in some embodiments, for interior temperature and interior humidity. A controller is used for limiting defrosting time to that sufficient to melt the boundary layer of ice, between 1 micron and 1 millimeter thick, and thereafter to prevent the boundary layer from re-freezing while removing the ice. In the case of defogging embodiments, the controller prevents the formation of condensation on surfaces by maintaining the surface temperature above the dew point. The controller of embodiments with sensors calculates the defrosting power as a function of ambient temperature, surface material's coefficient of heat transfer, and the distance between the heating layer and ice. For defogging, this controller of embodiments with sensors calculates defog power as a function of interior temperature, interior humidity, surface temperature, surface material's coefficient of heat transfer, and the distance between the heating layer and condensation.

[0046] In some embodiments, a controller described as a Type I controller, is connected to the high-voltage battery, e.g., via a high-voltage bus. In some embodiments, a controller described as a Type II controller, is connected to a DC / DC converter with output voltages of 12V-48V, e.g., via a low-voltage bus. The controller steps the voltage up in order to reach the optimal power level described above. In some embodiments, a controller described as a Type III controller, is directly embedded inside the DC / DC converter and controls the pulsing of the power provided by the DC / DC converter as a secondary output. This embodiment is the safest, simplest, and least costly to implement since it allows the DC / DC converter to utilize existing circuits for features like galvanic isolation (a typical OEM requirement for HV safety) and / or Electromagnetic Interference (EMI) filtering.

[0047] The present disclosure describes systems and methods for generating optimal power levels in EVs that are safe, simple, and minimize costs. These power levels can be achieved with high voltages (>60V) or low voltages ( < 60V). Some embodiments operate at low voltages, to achieve the low energy targets for defrosting in a vehicle. These methods are safer, simpler and less costly than providing high voltage levels to the glass because the lower voltage level is not considered harmful if there is human exposure. Also, a low-voltage solutions are not required to meet the OEM's higher requirements for high-voltage components.

[0048] The disclosed variety of methods and systems enable a vehicle maker flexibility on how they integrate defrosting and defogging systems into the electrical system of an EV in accordance therewith. The first type of power controller, the type I controller, is an independent control unit, that is connected to the HV battery on the input side and the windshield on the output side. The benefit of this system to the vehicle OEM is that it is easier to implement with few architecture changes to the electrical systems. The second type of power controller, the type II controller, as an independent control unit that is connected to the DC / DC converter on the input side and the windshield on the output side. There are two major benefits of this system. First, it can eliminate some of the electronics (e.g., galvanic isolation) by commonizing parts with less weight, size and lower costs. The second benefit is that this system is safer compared to the first option because the input voltage to this controller is low-voltage or lower voltage than the HV battery. The third type of power controller, the type III controller, has the hardware for this controller integrated into the vehicles's DC / DC converter, so that the DC / DC converter would have two outputs, one to manage the vehicle low-voltage systems and another to manage the pulses to the windshield. The benefit of this type of system is that it is more integrated with the existing electrical architecture such as the DC / DC converter. This system has fewer components, less weight, less size and less cost. In all cases the control unit (whether independent or integrated inside the DC / DC converter) would be connected to the vehicle Controller Area Network (CAN) system for sensor data exchange. The CAN bus is a robust vehicle bus standard designed to allow microcontrollers and devices to communicate with each other's applications without a host computer.

[0049] In some embodiments, the electrical pulses from this system provided to the windshield have a maximum voltage higher than 60 Volts. In this case, the windshield and the connecting wires and connectors are considered high-voltage components and have higher requirements for High-Voltage safety from standards bodies such as ISO and Vehicle Original Equipment Manufacturers (OEMs).

[0050] In some embodiments, the pulses going to the windshield have a maximum voltage of 60 Volts or lower. In this case the windshield and the connecting wires and connectors are not considered high-voltage components, and are known as low-voltage components which are considered much safer and having lower electrical safety requirement from vehicle makers (e g., OEMs).

[0051] The windshield defrosting / defogging system can be applied to hybrid vehicles or fully electric vehicles as well as commercial vehicles either that are electric, hybrid or have a 12V or 48V system with internal combustion engines. This include light duty trucks (class 3 or 4), medium duty (5 or 6) and heavy duty (class 7 or 8) or equivalent classifications in other regions.

[0052] In some embodiments, the system automatically keeps a vehicle's windshield fog-free without any intervention by the driver by using the proprietary defog system for providing efficient heat from the conductive layer in the windshield. It may also use a temperature sensor and a humidity sensor in the cabin. In another embodiment, a temperature sensor in the windshield is also used. This system keeps the glass temperature above the dew point so that moisture does not condense onto the windshield and create fog, which occludes the driver's vision of the road and creates a very unsafe condition.

[0053] A safety system described before, can detect cracks in the conductive layer that causes a change in resistance. A crack in this layer could cause allow human exposure to an electrical potential which is unsafe, so the detection of a crack automatically shuts down the output power to the windshield. A new and separate idea is that after the detection of a cracked windshield in the algorithm described previously, a message can be generated and sent via the CAN Bus to generate a Diagnostic Troubleshooting Code (DTC) or other alert notice, that the vehicle can communicate the need to replace the windshield to the driver, the dealer, and the OEM. To notify the driver, this can be done via an onboard service message to the car's driver display and / or a phone app for that vehicle. The DTC code can be sent to the OEM via their onboard diagnostics systems and / or telematics system to notify them of the service need. The OEM can contact a dealer, or other service provider, and allow them to notify the driver to replace the windshield. The dealer can also allow the vehicle owner to schedule the windshield replacement when the service part is at the dealer and there is an open service time.

[0054] FIG. 1 shows a detailed view of a windshield with a high-power defrosting system. A windshield 102 incorporates a transparent conductive layer 104 which acts as a heating element. Power for the heating element is supplied by a power supply 108, and the supply of power is regulated by controller 112 and switch 110. The controller 112 uses information from the sensors 114 to calculate optimum operation conditions and power delivery. In practice, the transparent conductive layer 104 will often incorporate several busbars 106, together called the heating apparatus. Although busbars 106 are illustrated in this figure at the top and bottom of the transparent conductive layer 104, a person skilled in the art will recognize that the busbars could be of varying number and locations around the transparent conductive layer 104.

[0055] FIG. 2 shows one embodiment where a Type I Power Controller 226 is connected to the High Voltage DC Bus 204 in the vehicle on the input side and to the Windshield 224 on the output side. FIG. 2 shows the connection diagram for this embodiment into an EV architecture. Typically, the High Voltage Battery 210 and the On-Board Charger 208 (that connects to the Charging Station 202) and Other High Voltage Loads 218 are connected to the High Voltage DC Bus 204. A DC / DC Converter 216 connects the High Voltage DC Bus 204 to the Low- voltage DC Bus 206, the DC / AC Converter 220 connects the High Voltage DC Bus 204 to the Electric Motors / Powertrain 222. The Low-voltage Battery 212 and Low-voltage Loads 214 are connected to the Low-voltage DC Bus 206. The Type I Power Controller 226 is an addition to the existing EV architecture as shown in the figure. This embodiment results in minimal changes to the current EV architecture because the defrosting and defogging system is directly connected to the high-voltage bus having access to the battery energy directly. In this architecture, the current power distribution does not need any change.

[0056] FIG. 3 shows a proposed controller block diagram for this embodiment. This usually include an input EMI Filter 304 and Galvanic Isolation 312. The EMI Filter 304 (to block conductive electromagnetic interference to the DC Bus) is connected to a DC Link 306 (local energy storage to facilitate quick energy conversion for the power stage) that is connected to a Full Bridge MOSFET 308 (converts DC to AC) on the input side of the Galvanic Isolation 312 (for safety and isolating the battery from the windshield). The output side of the Galvanic Isolation 312 is connected to a Synchronous Rectifier 314 (converts AC back to DC) and an Output Filter 318 (to remove high frequency noise on the output voltage). The Full Bridge MOSFET 308 is controlled through an Isolated Gate Driver 310 and the Synchronous Rectifier 314 is controlled through another Isolated Gate Driver 316; both gate drivers are operated using a dedicated Microcontroller (Defrost / Defog Algorithm) 324. The microcontroller manages sensor data from both the Power Sensors 320 (this include current and voltage sensors that are embedded inside the power controller for example) and the Windshield Sensors 322 (such as capacitive sensor and optional temperature sensor(s) that are embedded inside the windshield). The Type I Power Controller 226 is also connected to the Vehicle CAN Bus 302 for sensor data exchange with the vehicle. The vehicle Controller Area Network (CAN bus) is a robust vehicle bus standard designed to allow microcontrollers and devices to communicate with each other's applications without a host computer.

[0057] The three components: Full Bridge MOSFET 308, Galvanic Isolation 312, and Synchronous Rectifier 314 act (collectively) as a "voltage converter" controlled by the microcontroller, to deliver the appropriate voltage (and current), according to the pulsing schedule appropriate for PETD signal application to the windshield, one consequence of which is a lowering of voltage for low-voltage high-current embodiments in a high DC voltage bus context.

[0058] This embodiment can be flexible to work with either low-voltage or high-voltage output to the windshield. In the case of low-voltage, this will require higher currents and larger bus bars on the heated surfaces like the Windshield. This offers more flexibility to automakers to implement this technology based on the voltage levels of the vehicle and the resistance levels of the heating element such as the conductive layer in the glass. A low-voltage option such as less than 60V will be considered safer and have lower safety requirements from automakers. For example, high-voltage specifications will not apply to these low -voltage embodiments. In addition, embodiments that are below 100V will be safer than higher voltages such as 400V or 800V. Lower voltage ranges offer benefits for safety and design requirements. Such flexibility in the design of the controller is an advantage to work with various vehicle architectures such as voltage, conductive materials, resistance levels and current levels.

[0059] In some embodiments, in the context of high-current, low-voltage PETD signal delivery to the windshield, it should be understood that the Synchronous Rectifier 314 and Output Filter 318 on the output side of the Galvanic Isolation 312 are configured specifically for high-current and low-voltage signals, and provision of the same to the windshield.

[0060] FIG. 4 shows another embodiment where a Type II Power Controller 402 is connected to the Low-voltage DC Bus 206 that is connected to the DC / DC Converter 216. The DC / DC Converter 216 is a standard part in EVs that is used for the vehicle’s low-voltage systems, e.g., 12v, 24v, or 48v Systems (206). The Type II Power Controller 402 would be low-voltage on the input side and would control the pulses to the Windshield 224. FIG. 4 shows the connection diagram for this embodiment into an EV architecture. This controller is connected to the Low- voltage DC Bus and using a DC / DC converter it steps up / down the voltage accordingly to reference signals calculated by PETD algorithm. This architecture is more suitable for applications with windshields coated with a metal layer with lower sheet resistance (ohms per unit area).

[0061] FIG. 5 shows a proposed controller block diagram for this embodiment. In this embodiment, the low-voltage bus is used to supply power for defrosting and defogging cycles. The Type II Power Controller 402 is connected to the Low-voltage DC Bus 206 on the input side and the Windshield 224 on the output side. The EMI Filter 502 (to block conductive electromagnetic interference to the DC Bus) is connected to a DC Link 504 (local energy storage to facilitate quick energy conversion for the power stage) that is connected to a Multiphase Converter (No Galvanic Isolation) 506 (to adjust the output voltage level to the required value with galvanic isolation) and an Output Filter 510 (to remove high frequency noise on the output voltage). The Multi-phase Converter (No Galvanic Isolation) 506 is controlled through an Isolated Gate Driver 508 that is operated using a dedicated Microcontroller (Defrost / Defog Algorithm) 518. The microcontroller manages sensor data from both the Current Sensors 512, the Voltage Sensors 514 and the Windshield Sensors 322 (such as capacitive sensor and optional temperature sensor(s) that are embedded inside the windshield). The Type II Power Controller 402 is also connected to the Vehicle CAN Bus 302 for sensor data exchange with the vehicle.

[0062] The Multi-phase Converter (No Galvanic Isolation) 506 acts as a "voltage converter" controlled by the microcontroller, to deliver the appropriate voltage (and current), according to the pulsing schedule appropriate for PETD signal application to the windshield.

[0063] This architecture provides advantages in comparison with the previous one in regard to safety requirements because it can operate in a voltage range between the voltage bus and 60 V, which classifies it as a low-voltage system (voltage class "A" according to ISO 6469-3). This fact allows the usage of non-isolated DC / DC power converters which can operate without the galvanic isolation provided by bulky and expensive transformers. This saves significant space, weight and cost if the galvanic isolation is used in the existing DC / DC converter providing power to the Low-voltage DC Bus 206. However, because the power is being provided at a lower voltage, in some cases, the input current at the DC / DC converter may be higher in comparison with the previous architecture. To overcome this issue multiphase DC / DC converters with an interleaved operation could be used as the best option to implement the PETD algorithm.

[0064] In some embodiments, in the context of high-current, low-voltage PETD signal delivery to the windshield, it should be understood that the Output Filter 510 on the output side of the Multi-phase Converter (No Galvanic Isolation) 506 is configured specifically for high-current and low-voltage signals, and provision of the same to the windshield.

[0065] FIG. 6 shows another embodiment a Type III Power Controller 602 is used to combine the functions of both the DC / DC converter and the Defrost / Defog controller. The Type III Power Controller 602 would have two outputs, one to manage the vehicle low-voltage systems, e.g., 12V, 24V, or 48V Systems (206) and another to control the pulses to the Windshield 224. FIG. 6 shows the connection diagram for this embodiment into an EV architecture. This embodiment aims to optimize the usage of power electronic resources in electric or hybrid vehicles through the integration of a DC / DC converter currently present in all electrified vehicles. This new vehicular DC / DC converter is connected to the high-voltage bus and has two independent output ports, each one generating independent DC buses with different voltages and power availabilities. DC / DC converters with Single Input and Multiple Outputs (SIMO) are frequently designated as Multiport DC / DC converters. This structure has advantages over the previous topologies in terms of the number of power devices and conversion steps used because the systems resources (i.e., conversion devices) are shared. As a result, this architecture can achieve higher efficiency with low cost, centralized control and compact packaging. All these features have high value in automotive and vehicle applications.

[0066] FIG. 7 shows a proposed controller block diagram for this embodiment. The input port is connected to the vehicle’s high-voltage battery, and it is magnetically coupled through a multi -winding transformer (Galvanic Isolation 710) to the output ports 1 and 2, which are used for DC / DC converter and Defrosting / Defogging, respectively. The Type III Power Controller 602 is connected to the High Voltage DC Bus 204 on the input side and the Windshield 224 as well as the Low-voltage DC Bus 206 on the output side. The EMI Filter 702 (to block conductive electromagnetic interference to the DC Bus) is connected to a DC Link 704 (local energy storage to facilitate quick energy conversion for the power stage) that is connected to an Input Full Bridge MOSFET 706 (converts DC to AC) on the input side of the Galvanic Isolation 710 (for safety and isolating the battery from the windshield and the low -voltage DC Bus). One output side of the Galvanic Isolation 710 is connected to Output 1 Full Bridge MOSFET 712 (converts AC back to DC) and a DC Link 720. The other output side of the Galvanic Isolations 710 is connected to Output 2 Full Bridge MOSFET 716 (converts AC back to DC) and an Output Filter 722 (to remove high frequency noise on the output voltage). The Input Full Bridge MOSFET 706 is controlled through an Isolated Gate Driver 708, and the Output 1 Full Bridge MOSFET 712 and Output 2 Full Bridge MOSFET 716 are controlled through Isolated Gate Driver 714 and Isolated Gate Driver 718; all three gate drivers are operated using a dedicated Microcontroller (Microcontroller (DC / DC Converter Algorithm and Defrost / Defog Algorithm) 730. The microcontroller manages sensor date from both the Current Sensors 724, the Voltage Sensors 726 and the Windshield Sensors 728 (such as capacitive sensor and optional temperature sensor(s) that are embedded inside the windshield). The Type III Power Controller 602 is also connected to the Vehicle CAN Bus 302 for sensor data exchange with the vehicle.

[0067] The components: Input Full Bridge MOSFET 706, Galvanic Isolation 710, and Output 2 Full Bridge MOSFET 716 act (collectively) as a "voltage converter" controlled by the microcontroller, to deliver the appropriate voltage (and current), according to the pulsing schedule appropriate for PETD signal application to the windshield, one consequence of which is a lowering of voltage for low-voltage high-current embodiments in a high DC voltage bus context.

[0068] In alternate embodiments, the input side of the Galvanic Isolation 710 has two separate inputs for separate coupling of the Input Full Bridge MOSFET 706 respectively with the Output 1 Full Bridge MOSFET 712 and with the Output 2 Full Bridge MOSFET 716. In further embodiments, galvanic isolation is provided by two Galvanic Isolators (similar to the Galvanic Isolation 710 as shown) coupled between the Input Full Bridge MOSFET 706 and respectively the Output 1 Full Bridge MOSFET 712 and the Output 2 Full Bridge MOSFET 716. In further embodiments, there are two Input Full Bridge MOSFETs to operate each output channel separately.

[0069] In this DC / DC converter topology, the energy can be transferred from one port to another changing the phase shifts and duty cycles on each one of the three Full-Bridge MOSFETs (Input Full Bridge MOSFET 706, Output 1 Full Bridge MOSFET 712, and Output 2 Full Bridge MOSFET 716). In this application, there are energy storage devices connected to the input port (high-voltage battery) and first output port (low-voltage battery), which means that these two channels need a bi-directional energy-flowing capability. Each port has its own DC link and operates as local subsystem units, within the DC bus the power of each source can simply be controlled by regulating the source power / current with duty cycle as the control variable. This architecture implemented utilizing multiport DC / DC converters can extend the functionalities already present on regular automotive or vehicle DC / DC converters and integrate the high-efficient PETD technology for defrosting and defogging sharing resources as cables, connectors, enclosures, EMI filter, transformer, liquid cooling system and control unit which offers a significant level of savings in terms of space, weight and cost. This embodiment can be flexible to work with Defrosting / Defogging controller with either low-voltage or high- voltage to the windshield. In the case of low-voltage, this will require higher currents and larger bus bars on the heated surfaces like the Windshield. This offers more flexibility to automakers to implement this technology based on the voltage levels of the vehicle and the resistance levels of the heating element such as the conductive layer in the glass. A low-voltage option such as less than 60V will be considered more safe and have lower safety requirements from automakers. For example, high-voltage specifications will not apply to these low-voltage embodiments. In addition, embodiments that are below 100V will be safer than higher voltages such as 400V or 800V. Lower voltage ranges offer benefits for safety and design requirements. Such flexibility in the design of the controller is an advantage to work with various vehicle architectures such as voltage, conductive materials, resistance levels and current levels.

[0070] In some embodiments, in the context of high-current, low-voltage PETD signal delivery to the windshield, it should be understood that Output 2 Full Bridge MOSFET 716 and Output Filter 722 on the output side of the Galvanic Isolation 710 are configured specifically for high- current and low-voltage signals, and provision of the same to the windshield.

[0071] Although the above embodiments describe systems in the context of defrosting and defogging vehicle windshields, it should be understood that the above teachings are equally applicable to defrosting and / or defogging other surfaces of a vehicle including but not limited to side glass, rear glass, camera lenses, LiDAR, headlamps, ... etc. As with embodiments described above, the voltage and current levels of the electrical signals are modulated for appropriate application to these surfaces, and internal signal sensors as well as sensors proximate the surfaces may be used for monitoring the provision of the electrical signals to these surfaces.

[0072] As described before, the defrost / defog controller can be used to defog a surface by heating it to a temperature above the dew point which depends on the temperature and the relative humidity of the surroundings. Here, we combine the basic defogging function with additional sensors that are being added to vehicles along with the capability to detect when defogging is needed in order to automate the defogging feature. As a result of this feature, drivers will not need to experience fogged surfaces such as windshields, and do not need to push any buttons to initiate the defogging function. This feature provides additional safety and convenience to the driver. FIG. 8 shows the flowchart of the automated defogging feature using the defrost / defog controller. The controller will receive a signal from the Vehicle CAN Bus with information about the outside temperature, cabin temperature, cabin relative humidity (802). The controller will then calculate the dew point at the windshield interior surface (804) and optimize the pulses of power (frequency, amplitude, and run time) (806). The controller will apply optimized power to the transparent conductive layer inside the glass (808). The optimized power could be pulsed or not pulsed depending on the operating conditions. The process could be repeated after a set adjustable time, possibly between 30 seconds and 10 minutes (810). An optional glass temperature sensor could be used to improve the accuracy of the control. The windshield temperature would be allowed to fluctuate within a certain tolerance above the dew point to maintain the windshield fog free. This works, by keeping the glass above the dew point, so that humidity does not condense onto interior surfaces like the windshield or other glass surfaces. The benefit of this feature is that driver does not need to intervene, typically after the glass fogs up and then wait a minute or two for defogging to work. This feature prevents condensation or fogging on the glass surfaces automatically so that the glass does not ever fog up, creating a potentially dangerous situation.

[0073] Although the above description makes specific reference to PETD signals used to defrost and defog a windshield, it should be understood that although PETD may be preferable in some contexts, the systems and methods above contemplate more generally contemplate the application of any sufficiently effective intermittent or pulsed signals to the windshield. For greater clarity, the term "discontinuous electrical signals" in the context of electrical signals applied to the windshield for defrosting or defogging, shall be understood as including both intermittent signals and pulsed signals.

[0074] Although the method of FIG. 8 has been described in the context of preventing condensation on a vehicle windshield, it should be understood that the above teachings are equally applicable to keeping other surfaces of a vehicle free from unwanted condensation, including but not limited to side glass, rear glass, camera lenses, LiDAR, headlamps, ... etc.

[0075] As explained before, the defrost / defog controller tests the resistance of the windshield system prior to and during defrosting and defogging operations to guard against unsafe operation, safely and cost-effectively. This is particularly useful in the case of windshields, since problems can develop prior or during the defrosting process, such as a new chip in the windshield or the widening of a previously-minor crack, all of which would affect the resistance of the system. Since this layer could be 1 to 3 layers (e.g., Glass, PVB, glass) from the exterior surface, significant damage to the windshield will be necessary to damage the conductive layer. Here, we describe a new method to detect that a windshield has significant damage, typically more than a surface chip or surface crack. When we detect this, we can provide an output to alert the driver and automaker that the windshield needs replacement. FIG. 9 shows the flowchart of the crack detection reporting feature. Using the safety systems described earlier, a crack in the windshield can be detected (902) and reported to the driver, dealer, and OEM that the windshield needs to be replaced. The OEM can communicate to the dealer that the glass needs to be repaired and enable the dealer to schedule a windshield replacement service appointment when the replacement windshield has been received and the repair shop has an open service time available. This will increase driving safety and the chance of further damage to the windshield. Once a crack is detected with the defrost / defog controller, a signal will be sent to the vehicle CAN Bus with an error message or a Diagnostic Troubleshooting Code (DTC) (904). This DTC error message can communicate to the driver, the dealer, and the OEM, the need for a replacement windshield. To notify the driver, this can be done via an onboard service message to the car's driver display and / or a phone app for that vehicle (906). The DTC code can be sent to the OEM via their onboard diagnostics systems that communicate via cellular telematics (e.g., 5G networks) (910) or other methods to notify them of the need so that they can contact a dealer, or other service provider, and allow them to notify the driver to replace the windshield (908). The dealer can also allow the vehicle owner to schedule the windshield replacement when the service part is at the dealer and when there is open service time.

[0076] Although the method of FIG. 9 has been described in the context of replacement or repair of vehicle windshields having associated defrosting and / or defogging systems, it should be understood that the above teachings are equally applicable in the context of replacement or repair of other vehicle surfaces or components comprising them, having similar associated defrosting and / or defogging systems. Such surfaces of the vehicle include, but are not limited to, side glass, rear glass, camera lenses, LiDAR, headlamps, ... etc. The invention is not intended to be limited to the embodiments described herein, but rather the invention is intended to be applied widely within the scope of the inventive concept as defined in the specification as a whole including the appended claims.

Claims

CLAIMSWHAT IS CLAIMED IS:

1. A system for defogging and defrosting a vehicle surface comprising: a vehicle surface adapted to receive discontinuous electrical signals for application to said vehicle surface; at least one DC bus; and a power controller for providing the electrical signals to the vehicle surface, the power controller coupled to a first DC bus of the at least one DC bus via an input EMI filter, coupled to the vehicle surface via an output filter, and comprising a voltage converter controlled by a microcontroller for modulating voltage and current levels for the electrical signals, and internal signal sensors for monitoring the provision of electrical signals to the vehicle surface.

2. The system of claim 1, wherein the electrical signals provided to the vehicle surface are low-voltage high-current signals, and the output filter of the power controller comprises a low- voltage high-current output filter.

3. The system of claim 2, wherein the voltage converter of the power controller comprises galvanic isolation coupled between the EMI filter and the low-voltage high-current output filter.

4. The system of claim 3, wherein the first DC bus comprises a high-voltage DC bus, and wherein the voltage converter comprises a synchronous rectifier coupled between the galvanic isolation and the low-voltage high-current output filter configured for low-voltage high-current operation, and a full bridge MOSFET coupled between the input EMI filter and the galvanic isolation.

5. The system of claim 4, wherein the power controller further comprises a first isolated gate driver coupled between the microcontroller and the full bridge MOSFET and a second isolated gate driver coupled between the microcontroller and the synchronous rectifier, the first and second isolated gate drivers for use by the microcontroller in controlling a pulsing of the electrical signals.

6. The system of claim 3, wherein the first DC bus comprises a high-voltage DC bus, wherein the at least one DC bus comprises a low-voltage DC bus, wherein the power controller is coupled to the low-voltage DC bus, and wherein the voltage converter comprises an output full bridge MOSFET configured for low-voltage high-current operation and coupled between the galvanic isolation and the low-voltage high-current output filter, and an input full bridge MOSFET coupled between the input EMI filter and the galvanic isolation.

7. The system of claim 6, wherein the power controller further comprises a first isolated gate driver coupled between the microcontroller and the input full bridge MOSFET and a second isolated gate driver coupled between the microcontroller and the output full bridge MOSFET, the first and second isolated gate drivers for use by the microcontroller in controlling a pulsing of the electrical signals.

8. The system of claim 6, wherein the power controller further comprises a further output full bridge MOSFET coupled between the galvanic isolation and the low-voltage DC bus, and an isolated gate driver coupled between the microcontroller and the further output full bridge MOSFET, whereby the power controller performs DC / DC conversion between the high-voltage DC bus and the low-voltage DC bus.

9. The system of claim 2, wherein the first DC bus comprises a low-voltage DC bus, and wherein the voltage converter comprises, coupled between the EMI filter and the low-voltage high-current output filter, a multi-phase converter without galvanic isolation for adjusting voltage levels of the electrical signals.

10. The system of claim 9, wherein the power controller further comprises an isolated gate driver coupled between the microcontroller and the multi-phase converter, the isolated gate driver for use by the microcontroller in controlling a pulsing of the electrical signals.

11. The system of claim 2, wherein the power controller further comprises vehicle surface sensors for generating vehicle surface data for use by the microcontroller in said modulating voltage and current levels for the electrical signals.

12. The system of claim 1, wherein the discontinuous electrical signals comprise pulse electro thermal defrosting (PETD) signals.

13. The system of claim 1, wherein the vehicle surface comprises a windshield.

14. A method of preventing condensation on a vehicle surface of a vehicle, the method comprising: gathering data from sensors of the vehicle; determining a dew point from the data; and controlling a temperature of the vehicle surface to remain above the dewpoint with discontinuous electrical signals provided to the vehicle surface.

15. The method of claim 14, wherein the vehicle surface comprises a windshield.

16. The method of claim 14, wherein the sensors of the vehicle comprise at least one of a cabin temperature sensor, a cabin relative humidity sensor, an outside temperature sensor, and a vehicle surface temperature sensor.

17. The method of claim 16, further comprising: determining parameters for driving the electrical signals from the data measured from the sensors.

18. The method of claim 17, wherein data from the sensors is sampled intermittently at an adjustable time period determined with use of the data measured from the sensors.

19. A method of automatic notification of a defect in a vehicle surface of a vehicle, the method comprising: detecting the defect in the vehicle surface; sending a signal to the vehicle Controller Area Network (CAN) bus with a Diagnostic Troubleshooting Code (DTC) error message; and communicating a notification of the DTC error thereby notifying a defect in the vehicle surface for repair or replacement.

20. The method of claim 19, wherein the vehicle surface comprises a windshield.

21. The method of claim 19, wherein communicating the notification comprises sending an error message to a driver of the vehicle via one or more of local vehicle display and electronic notification to electronic device of the driver.

22. The method of claim 19, wherein communicating the notification comprises sending an error message to an Original Equipment Manufacturer (OEM) by the vehicle.

23. The method of claim 19, further comprising sending the communicated notification to a service provider for facilitating repair or replacement of the vehicle surface.

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