A SPD dimming canopy controller and its control method

Abstract

This invention discloses an SPD dimming canopy controller and its control method, including a low-voltage zone circuit, a high-voltage zone circuit, and a high-low voltage isolation circuit connected between the low-voltage zone circuit and the high-voltage zone circuit. The power supply port of the low-voltage zone circuit is connected to the vehicle battery and the high-low voltage isolation circuit respectively, and the LIN communication interface is connected to the LNG bus transceiver via the LIN bus. The low-voltage zone circuit is used to receive dimming commands from the vehicle network through the LNG bus transceiver and transmit the dimming commands to the high-low voltage isolation circuit, and to supply power to the high-low voltage isolation circuit. The high-low voltage isolation circuit is used to transmit the dimming commands to the high-voltage zone circuit and supply the low-voltage zone voltage to the high-voltage zone. The high-voltage zone circuit is used to invert the high-voltage DC voltage into the high-voltage AC voltage required to drive the SPD diaphragm according to the received dimming commands. This invention utilizes the high-low voltage isolation circuit to completely isolate the low-voltage vehicle network from the high-voltage drive circuit, significantly improving the electrical safety and anti-interference capability of the system.

Description

Technical Field

[0001] This invention relates to the fields of automotive electronics and intelligent dimming technology, and in particular to an SPD dimming canopy controller and its control method. Background Technology

[0002] Suspended particle device (SPD) dimming technology, as an advanced intelligent dimming solution, has been widely used in automotive sunroofs, side windows, and other fields. SPD films can achieve stepless continuous adjustment of light transmittance by applying an AC voltage of 0-110V. Compared with technologies such as PDLC, SPD has advantages such as power-off memory, a wide continuous dimming range, and high visual clarity.

[0003] However, SPDs require high-voltage AC power, which contradicts the low-voltage DC power supply environment of automobiles. Some existing SPD controller solutions either use bulky and inefficient power frequency transformers or complex multi-stage conversion circuits, resulting in high system costs, reduced reliability, poor dimming response smoothness, and potential safety hazards in high- and low-voltage isolation. Summary of the Invention

[0004] In view of this, the present invention provides an SPD dimming canopy controller and its control method to solve the problems existing in the background art.

[0005] A SPD dimming canopy controller includes a low-voltage zone circuit, a high-voltage zone circuit, and a high-low voltage isolation circuit connected between the low-voltage zone circuit and the high-voltage zone circuit. The power supply ports of the low-voltage zone circuit are connected to the vehicle battery and the high-low voltage isolation circuit respectively. The LIN communication interface is connected to the LNG bus transceiver through the LIN bus. The low-voltage zone circuit is used to receive dimming commands from the vehicle network through the LNG bus transceiver and transmit the dimming commands to the high-low voltage isolation circuit, and to supply power to the high-low voltage isolation circuit. The high-low voltage isolation circuit is used to transmit dimming commands to the high-voltage circuit and to supply the low-voltage voltage to the high-voltage circuit. The high-voltage circuit is used to invert the high-voltage DC voltage into the high-voltage AC voltage required to drive the SPD film according to the received dimming command.

[0006] Preferably, the high-low voltage isolation circuit includes a digital isolator and a flyback isolation power supply. The low-voltage side UART serial port of the digital isolator is connected to the UART serial port of the LIN communication interface circuit of the low-voltage zone circuit, and the high-voltage side UART serial port of the digital isolator is connected to the UART serial port of the high-voltage MCU of the high-voltage zone circuit. The digital isolator is used to transmit the dimming command it receives to the high-voltage MCU of the high-voltage zone circuit and to supply power to the high-voltage MCU. The flyback isolation power supply has its first power supply terminal connected to the low-voltage circuit and its second power supply terminal connected to the high-voltage circuit. The flyback isolation power supply is used to transmit the DC voltage from the low-voltage region to the high-voltage region.

[0007] Preferably, the low-voltage zone circuit includes a low-voltage power supply circuit, a LIN communication interface circuit, and a low-voltage MCU. The first power port of the low-voltage power supply circuit is connected to the vehicle battery, the second power port is connected to the first power port of the LIN communication interface circuit, and the third power port is connected to the flyback isolation power supply. The low-voltage power supply circuit is used to convert the vehicle voltage of the vehicle battery into the first DC voltage to supply the LIN communication interface circuit and the flyback isolation power supply. The second power supply port of the LIN communication interface circuit is connected to the low-voltage MCU. The LIN communication interface of the LIN communication interface circuit is connected to the LIN bus. The UART serial port of the LIN communication interface circuit is connected to the UART serial port of the low-voltage MCU. The LIN communication interface circuit is used to transmit the dimming command received from the vehicle network to the digital isolator and convert the first DC voltage into the second DC voltage to supply the low-voltage MCU.

[0008] Preferably, the high-voltage zone circuit includes a high-voltage MCU, a BOOST boost circuit, and a half-bridge inverter circuit. The high-voltage MCU is used to generate a PWM signal to control the half-bridge inverter circuit according to the received dimming command. The PWM signal output terminal of the high-voltage MCU is connected to the PWM signal input terminal of the half-bridge inverter circuit. The BOOST boost circuit is used to boost the first DC voltage to a high voltage DC voltage and supply it to the half-bridge inverter circuit; The half-bridge inverter circuit is used to invert the high-voltage DC voltage into the high-voltage AC voltage required to drive the SPD diaphragm according to the PWM signal.

[0009] Preferably, the high-voltage zone circuit further includes an output detection circuit, which is used to collect the high-voltage AC voltage supplied to the SPD diaphragm in real time and transmit the collected voltage value to the high-voltage MCU.

[0010] Preferably, the output detection circuit is connected in series with a sampling resistor in the output loop of the current commutation circuit and an operational amplifier circuit for multi-stage amplification of the acquired output voltage.

[0011] Preferably, the high-voltage zone circuit further includes an NTC temperature detection circuit, which is used to detect the temperature of the canopy or key components in real time and transmit the collected temperature data to the high-voltage MCU.

[0012] Preferably, the output terminal of the half-bridge inverter circuit is further connected to an LC filter circuit for filtering out switching frequency harmonics.

[0013] Preferably, the half-bridge inverter circuit includes a pulsating DC shaping circuit and a current commutation circuit. The pulsating DC shaping circuit generates a pulsating voltage according to the PWM signal and transmits it to the current commutation circuit. The current commutation circuit performs current commutation on the pulsating voltage at zero point to output a high-voltage DC voltage and delivers the high-voltage DC voltage to the drive SPD diaphragm.

[0014] A control method for an SPD dimming canopy controller specifically includes the following steps: S1, the low-voltage MCU receives dimming commands from the body controller or manual switch through the vehicle network; S2, the low-voltage MCU sends the dimming command to the high-voltage MCU through the digital isolator; S3, the high-voltage MCU determines the corresponding effective value of the target AC voltage according to the dimming command; S4, the high-voltage MCU acquires the actual output voltage feedback value collected by the output detection circuit in real time, and dynamically adjusts the duty cycle of its output PWM signal according to the deviation between the effective value of the target AC voltage and the actual output voltage feedback value through a closed-loop control algorithm.

[0015] S5, the PWM signal drives the half-bridge inverter circuit to work, so that the effective value of the AC voltage finally output to the canopy is stabilized at the target value, thereby realizing precise control of the light transmittance of the SPD dimming canopy.

[0016] Preferably, in step S3, the high-voltage MCU looks up the transmittance-voltage mapping table stored in its internal memory, or converts the dimming command into the effective value of the target AC voltage according to the calculation model.

[0017] Preferably, the method further includes step S6, whereby the output detection circuit acquires the high-voltage AC voltage supplied to the SPD diaphragm in real time and feeds back the acquired voltage value to the high-voltage MCU, and / or the NTC temperature detection circuit detects the canopy temperature or the temperature of key components in real time and feeds back the acquired temperature data to the high-voltage MCU. When the voltage and / or temperature exceed the set threshold, the high-voltage MCU issues an alarm and protection command.

[0018] The beneficial effects of this invention are: 1. High-low voltage isolation design: This application sets up a high-low voltage isolation circuit between the low-voltage vehicle network and the high-voltage drive circuit. The high-low voltage isolation circuit completely isolates the low-voltage vehicle network from the high-voltage drive circuit, fundamentally eliminating the risk of high voltage entering the low-voltage network and significantly improving the electrical safety and anti-interference capability of the system.

[0019] 2. Integrated Intelligent Control: This application adopts a dual MCU architecture. The low-voltage MCU is responsible for communication, while the high-voltage MCU specializes in high-voltage inversion and regulation. The division of labor is clear, the dimming command transmission is stable, and the PWM control accuracy is high. The dual MCU architecture realizes functional decoupling and efficient collaboration. This architecture facilitates the implementation of complex control strategies, status monitoring and intelligent protection functions (such as temperature compensation and fault diagnosis), thereby improving the overall intelligence level of the system.

[0020] 3. Smooth and continuous dimming: Based on half-bridge inverter and closed-loop feedback control, it can output an AC voltage with continuously adjustable effective value, perfectly matching the continuous dimming characteristics of SPD film and eliminating the dimming step sensation.

[0021] 4. Comprehensive protection functions: It integrates output overvoltage, overcurrent, and overtemperature detection and protection circuits, which can respond to various abnormal operating conditions in a timely manner, effectively protect the controller itself and the valuable SPD canopy components, and improve the long-term working reliability of the controller and canopy module.

[0022] 5. High precision and smoothness: This invention uses a dedicated microcontroller on the high-voltage side for real-time closed-loop control. Combined with high-precision output detection and advanced control algorithms (such as PID), it can accurately, stably and continuously adjust the effective value of the output AC voltage, perfectly matching the continuous dimming characteristics of the SPD diaphragm and completely eliminating the step sensation and flicker during the dimming process. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a system principle block diagram according to an embodiment of the present invention.

[0025] Figure 2 This is a schematic diagram of the low-voltage power supply circuit in an embodiment of the present invention.

[0026] Figure 3 This is a schematic diagram of the LIN communication interface circuit in an embodiment of the present invention.

[0027] Figure 4 This is a circuit diagram of a low-voltage MCU in an embodiment of the present invention.

[0028] Figure 5 This is a schematic diagram of a digital isolated communication circuit in an embodiment of the present invention.

[0029] Figure 6 This is a schematic diagram of a flyback isolation power supply circuit in an embodiment of the present invention.

[0030] Figure 7 This is a schematic diagram of a high-voltage MCU circuit in an embodiment of the present invention.

[0031] Figure 8 This is a schematic diagram of the Boost converter circuit in an embodiment of the present invention.

[0032] Figure 9 This is a schematic diagram of the pulsating DC shaping circuit in an embodiment of the present invention.

[0033] Figure 10 This is a schematic diagram of the current commutation circuit in an embodiment of the present invention.

[0034] Figure 11 This is a schematic diagram of the output detection circuit in an embodiment of the present invention. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0036] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0037] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various information, such information should not be limited to these terms and should not be construed as indicating or implying relative importance. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0038] To better understand the technical solution of the present invention, the present invention will be described in detail below with reference to the accompanying drawings.

[0039] This invention provides an SPD dimming canopy controller, including a low-voltage zone circuit, a high-voltage zone circuit, and a high-low voltage isolation circuit connected between the low-voltage zone circuit and the high-voltage zone circuit; The power supply ports of the low-voltage zone circuit are connected to the vehicle battery and the high-low voltage isolation circuit respectively. The LIN communication interface is connected to the LNG bus transceiver through the LIN bus. The low-voltage zone circuit is used to receive dimming commands from the vehicle network through the LNG bus transceiver and transmit the dimming commands to the high-low voltage isolation circuit, and to supply power to the high-low voltage isolation circuit. The high-low voltage isolation circuit is used to transmit the dimming command to the high-voltage circuit and to supply the low-voltage voltage to the high-voltage circuit. The high-voltage circuit is used to invert the high-voltage DC voltage into the high-voltage AC voltage required to drive the SPD film according to the received dimming command.

[0040] Specifically, the low-voltage circuit includes a low-voltage power supply circuit, a LIN communication interface circuit, and a low-voltage MCU; the high-low voltage isolation circuit includes a digital isolator and a flyback isolation power supply; and the high-voltage circuit includes a high-voltage MCU, a BOOST boost circuit, and a half-bridge inverter circuit.

[0041] The low-voltage power supply circuit converts the vehicle battery's on-board voltage into a first DC voltage to supply the LIN communication interface circuit and the flyback isolation power supply. The first power port of the low-voltage power supply circuit is connected to the vehicle battery, the second power port is connected to the first power port of the LIN communication interface circuit, and the third power port is connected to the flyback isolation power supply.

[0042] like Figure 2 As shown, Figure 2 The circuit diagram for the low-voltage power supply circuit includes an input protection and filtering unit, a power switch control unit, and a power output distribution unit. The input protection and filtering unit consists of a 4-pin connector, a reverse polarity protection diode D26, a transient voltage suppressor diode D23, a common-mode filter, and a differential-mode filter. The 4-pin connector serves as the input port for the low-voltage power supply circuit, with pins 1 and 2 (VIN+, VIN-) connected to the positive and negative terminals of the vehicle battery, respectively. The reverse polarity protection diode D26 is connected in series between pin 4 of the 4-pin connector and ground (L_GND). If the vehicle battery power supply is reversed, the reverse polarity protection diode D26 is cut off, thus protecting the subsequent circuitry. When the vehicle battery power supply is normally connected, the reverse polarity protection diode D26 is turned on. The transient voltage suppressor diode D23 is connected in parallel across the input power supply terminals (between VIN+ and VIN-) for... The system absorbs transient high-voltage pulses (such as surges) from the input power supply to protect subsequent circuits. The common-mode filter (FB2, FB4, C1, C5), composed of ferrite beads (FB2, FB4) and capacitors (C1, C5), is used to filter out common-mode noise from the input power supply. The multi-stage LC filter network (L1, C2, C6, C63, C4, C3, FB1, FB3), composed of inductor L1, multiple capacitors (C2, C63, C4, C3), and ferrite beads (FB1, FB3), is used to filter out differential-mode noise from the input power supply, resulting in a smoother input voltage. After the vehicle battery is connected to the 4-pin connector, the input power supply passes through the common-mode filter and the multi-stage LC filter network, filtering out high-frequency noise and interference to obtain a relatively clean DC voltage VIN+.

[0043] The power output distribution unit includes an MCU power supply branch and an analog power supply branch. The MCU power supply branch consists of an LC filter network and diode D2. The LC filter network comprises inductor L2, resistors R61 and R54, and capacitors C7 and C64. The DC voltage VIN+ output from the input protection and filtering unit is filtered by the LC filter network to further reduce ripple and noise. Then, it outputs a 12V DC voltage from the L_12V_MCU interface through diode D2. This voltage supplies the LIN communication interface circuit. Figure 3 The LIN communication interface circuit shown has an L_12V_MCU interface; the analog power supply branch includes a filter network and an inductor L100, and the filter network consists of capacitors C10, C11 and C12.

[0044] The power switch control unit includes a gate drive circuit, a main switch transistor, and a filter unit. Resistors R1, R2, and R3, and diode D3 constitute the gate drive circuit. Resistors R2 and R3 form the base bias circuit for driving transistor Q2, and resistor R1 is the pull-up resistor for the gate of the main switch transistor Q1. When power needs to be supplied to the backflash isolation power supply, the low-voltage MCU sets its MCU_Vin pin to a high level (the low-voltage MCU's MCU_Vin pin is...). Figure 2The MCU_Vin interface is connected, which turns on transistor Q2. After transistor Q2 is turned on, its collector potential is pulled low, which pulls down the gate (G) potential of the main switch transistor Q1 through diode D3. Since the main switch transistor Q1 is a P-channel MOSFET, when the gate potential is lower than the source (S) potential (i.e., the input voltage), the main switch transistor Q1 is turned on. The DC voltage VIN+ output by the input protection and filtering unit is filtered by the filter network composed of capacitors C10, C11 and C12, and then filtered by inductor L100, outputting a 12V DC voltage from the L_12V interface. This 12V DC voltage flows to Figure 5 The L_12V interface of the flyback isolation power supply is shown. When power is not needed for the flyback isolation power supply, the low-voltage MCU sets its MCU_Vin to a low level, causing the driver transistor Q2 to turn off. After the driver transistor Q2 turns off, the gate of the main switch Q1 is pulled up to the same potential as the source (S) through the pull-up resistor R1. At this time, the gate voltage of the main switch Q1 is 0, the main switch Q1 is turned off, and the L_12V voltage output is cut off.

[0045] The second power supply port of the LIN communication interface circuit is connected to the low-voltage MCU. The LIN communication interface circuit is connected to the LIN bus. The UART serial port of the LIN communication interface circuit is connected to the UART serial port of the low-voltage MCU. The LIN communication interface circuit is used to transmit the dimming command received from the vehicle network to the digital isolator and convert the first DC voltage (12V DC voltage) into the second DC voltage (5V DC voltage) to supply the low-voltage MCU.

[0046] like Figure 3 As shown, Figure 3 This is a circuit schematic of the LIN communication interface circuit, which includes an SBC converter chip. This chip converts LIN signals (control commands) received from the LIN bus into UART signals for transmission to the low-voltage MCU, while simultaneously providing 5V voltage to the low-voltage MCU. The VBAT pin of the SBC converter chip is connected to... Figure 2The SBC converter chip is connected to the L_12V_MCU interface, with the GND pin grounded. A capacitor C15 is connected in series between the VBAT pin and the GND pin. The VCC pin outputs 5V to provide voltage to the low-voltage MCU, meaning the VCC pin is connected to the VCC interface of the low-voltage MCU. The LIN pin of the SBC converter chip is connected to a filter network and a bidirectional transient voltage suppressor diode D4. This filter network consists of capacitors C16 and C17 and a ferrite bead FB5. The LIN signal (control command) input from the LIN interface is filtered by the filter network and then enters the SBC converter chip. The SBC converter chip converts the LIN signal into a UART signal. The TXD and RXD pins of the SBC converter chip are connected to the TXD0 and RXD0 pins of the low-voltage MCU, respectively. The UART signal is input to the low-voltage MCU from the TXD or RXD pin of the SBC converter chip.

[0047] like Figure 4 As shown, Figure 4 This is the circuit schematic of a low-voltage MCU. Its VDD pin is connected to a filter network, which consists of capacitors C20, C21, C22, and C23. The 5V output from this pin is filtered by the filter network and then supplied to the L_5V_A interface of the digital isolator to power the isolator. Pins 12, 13, 15, and 16 of the low-voltage MCU are respectively connected to… Figure 5 The LMCU_RX and LMCU_TX, LIN_TX and LIN_RX pins of the digital isolator shown are connected to transmit UART signals to the digital isolator.

[0048] The low-voltage side UART serial port of the digital isolator is connected to the UART serial port of the low-voltage MCU, and the high-voltage side UART serial port of the digital isolator is connected to the UART serial port of the high-voltage MCU in the high-voltage zone circuit. The digital isolator is used to transmit the UART signal (dimming command) it receives to the high-voltage MCU in the high-voltage zone circuit and to supply power to the high-voltage MCU.

[0049] like Figure 5 As shown, Figure 5 This is the circuit schematic of a digital isolator, with its H_5V_B interface connected to... Figure 7 The H_5V_B interface of the high-voltage MCU is connected to provide a 5V operating voltage to the high-voltage MCU; the MCU_LRX and MCU_LTX, MCU_UART_TX and MCU_UART_RX pins of the digital isolator are connected to the corresponding pins of the high-voltage MCU. Figure 5The U2 and U4 chips (ISO6721 series) are connected between the high and low voltage areas. Chip U2 is responsible for UART communication between the two MCUs in the high and low voltage areas; chip U4 is responsible for connecting the LIN transceiver in the low voltage area to the MCU in the high voltage area, achieving an electrical isolation strength of up to several kilovolts and ensuring the safety of signal transmission.

[0050] The first power supply terminal of the flyback isolation power supply is connected to the L_12V of the low-voltage power supply circuit, and the second power supply terminal is connected to the high-voltage circuit. The flyback isolation power supply is used to transmit the DC voltage from the low-voltage area to the high-voltage area.

[0051] like Figure 7 As shown, Figure 7 This is the circuit schematic of a high-voltage MCU, which uses a 64-pin MCU. It is powered by a digital isolator (DIS) at 5V and uses DIS U4 for LIN communication and DIS U2 to help the low-voltage MCU enter standby mode (turning off the high-voltage power supply to reduce standby power consumption). Its three complementary PWM output pins (1_H&1_L, 2_H&2_L, 12_H&12_L) are connected to the input of the half-bridge inverter circuit to control the subsequent inverter circuit. Its ANI15 pin is connected to an external NTC temperature sensing circuit to acquire the load (skylight) temperature. The high-voltage MCU's internal timer generates two complementary PWM signals with dead time (PWM_H, PWM_L), which are output to the gate driver.

[0052] The high-voltage MCU generates a PWM signal to control the half-bridge inverter circuit based on the received dimming command. The PWM signal output terminal of the high-voltage MCU is connected to the PWM signal input terminal of the half-bridge inverter circuit. like Figure 6 As shown, Figure 6 The circuit diagram is for a flyback isolation power supply. Figure 6 The flyback isolation power supply uses the flyback controller U5 (LT8306) as its core to control the isolation transformer to supply power to the high-voltage area. The primary winding of the transformer is powered by 12V from the low-voltage area, and the two secondary windings are connected in parallel to increase the power output. After rectification by Schottky diodes, a 12V DC voltage is generated, thus completing the 12V power transmission from the low-voltage area to the high-voltage area.

[0053] Figure 6 The flyback isolated power supply consists of several parts, including an input filter unit, a flyback controller U5, a transformer, a feedback network, and an enable / undervoltage lockout circuit. The input filter unit includes a filter circuit composed of capacitors C39, C40, C41, and C42, and a Zener diode Z1. Capacitors C39, C40, C41, and C42 are connected in parallel between L_12V and L_GND to filter out high-frequency noise and ripple at the input. Zener diode Z1 is also connected between L_12V and L_GND to provide input overvoltage protection. The VIN pin of the flyback controller U5 is connected to L_12V to receive the input power; the GND pin is connected to L_GND; the GATE pin is connected to the gate (G) of the power switch Q3 through a resistor to drive the gate (G) of the external power switch Q3; the SENSE pin is connected to one end of the current sensing resistor R26 to detect the primary peak current; the RFB pin is connected to the auxiliary winding of the transformer through resistor R26 to detect the output voltage and adjust the duty cycle; the EN / UVLO pin is the enable / undervoltage lockout terminal, and the EN / UVLO pin is connected to the input power supply Flybock_EN through a resistor divider network (R29, R31, Q14) to set the undervoltage lockout and enable logic; the drain (D) of the power switch Q3 is connected to pin 1 of the primary winding (Pri primary_1) of the transformer T1, and the source (S) of the power switch Q3 is connected to one end of the current sensing resistor R30, the other end of the current sensing resistor R30 is grounded.

[0054] The primary winding (Pri) of transformer T1 has pins 1-2 connected to the main circuit, and pins 3-4-5 forming auxiliary windings. The secondary winding (Sec) consists of two secondary windings (Sec secondary_1 and Sec secondary_2), corresponding to pins 6-7 and 9-10 respectively. Pin 1-2 connects to diode D6 and resistor R24 ​​to power the chip or provide feedback signals. Z1 is a Zener diode for overvoltage protection. Pin 10 on the secondary winding outputs an AC pulse, which is rectified into a pulsating DC current by rectifier diode D7. A filter capacitor C44 and a load resistor R25 are connected in series and then in parallel with rectifier diode D7 to smooth the rectified pulsed DC current, resulting in a stable 12V DC voltage output to the BOOST boost circuit. Specifically, its H_12V_A interface is connected to the H_12V interface of the BOOST boost circuit.

[0055] When the GATE pin of control chip U5 outputs a high level, it drives the power switch Q3 to conduct. The input current flows from L_12V through the primary winding of the transformer (pins 1-2) and the power switch Q3 to ground. At this time, the primary inductance of the transformer stores energy. Due to the reverse polarity of the transformer, the rectifier diode D7 on the secondary side of the transformer is in a reverse cutoff state, and there is no current output on the secondary side. When the GATE pin of control chip U5 outputs a low level, the power switch Q3 is turned off, the primary current is cut off, the transformer magnetic field collapses, the polarity reverses, a forward voltage is induced on the secondary side, and the rectifier diode D7 conducts. The energy stored in the transformer is transferred to the output capacitor C44 and the BOOST boost circuit through the rectifier diode D7, charging C44 and providing 12V voltage to the BOOST boost circuit.

[0056] The BOOST boost circuit is used to boost the first DC voltage to a high voltage DC voltage and supply it to the half-bridge inverter circuit.

[0057] like Figure 8 As shown, Figure 8 This is the circuit schematic for the BOOST boost circuit. Capacitors C65 and C68 form an input filter to remove high-frequency noise from the input power supply and provide transient current to the circuit. Chip U9 (LM5022QDGSRQ1) is the core controller chip of this circuit. The OUT pin of chip U9 is connected to the gate (G) of the switching MOSFET Q5 through the gate drive resistor R49. R42 and R41 form a gate pull-down / pull-up network to ensure that the switching MOSFET Q5 is in the off state when chip U9 is not working. Diodes D11, D12, and D13 are rectifier diodes connected in series. The use of three diodes in series is to share the reverse voltage of the high voltage (150V) and prevent the breakdown of a single diode. Capacitors C77, C78, ​​C79, C75, and C82... The output filter capacitor is used to smooth the output voltage and reduce ripple; resistors R43 and R47 form a resistor divider network to sample the output voltage. Chip U9 adjusts the PWM duty cycle by comparing the voltage at the FB pin with the internal reference voltage, thereby stabilizing the output voltage; resistor R48 is connected to the RT / SYNC pin of chip U9 to set the switching frequency; capacitor C84 is connected to the COMP pin of chip U9 and is usually used for loop compensation or soft-start settings; the UVLO pin of chip U9 is connected to an external control unit composed of transistors Q200 and Q202. Through this external control unit, the external logic signal BOOST_CONTROL can be used to turn the BOOST boost circuit on or off.

[0058] When chip U9 (LM5022QDGSRQ1) outputs a high-level drive signal to the gate of MOSFET (Q5), Q5 turns on. Current flows from the input power supply H_12V through inductor L5, then through the conducting MOSFET Q5 and sensing resistors R44 / R45 to ground. At this time, inductor L5 stores magnetic energy, and the current rises linearly. Simultaneously, the output capacitors (C77-C82) discharge to the load, maintaining the output voltage, and diodes D11-D13 are in reverse cutoff. When U9 stops outputting the drive signal, Q5 turns off. Since the inductor current cannot change abruptly, inductor L5 generates a reverse electromotive force (negative on the left, positive on the right), and its voltage is superimposed on the input voltage. The superimposed voltage is higher than the output voltage V_150V, and diodes D11-D13 conduct in the forward direction. The energy stored in the inductor charges the output capacitor through the diodes and supplies power to the half-bridge inverter circuit. This circuit uses resistors R43 and R47 to perform voltage division sampling of V_150V and sends it to the FB pin of chip U9. If the output voltage drops (e.g., the load increases), the voltage on the FB pin decreases, and the internal error amplifier of chip U9 controls the PWM logic to increase the duty cycle (the MOSFET conduction time becomes longer), so that the inductor stores more energy, thereby increasing the output voltage. Conversely, if the output voltage increases, the duty cycle decreases, reducing the output voltage, thereby raising the 12V voltage of the flyback isolation power supply to a stable high-voltage DC bus voltage of 150V (e.g., V_150V), which is then supplied to the half-bridge inverter circuit.

[0059] The half-bridge inverter circuit is used to invert the high-voltage DC voltage into the high-voltage AC voltage required to drive the SPD diaphragm according to the PWM signal.

[0060] The half-bridge inverter circuit includes a pulsating DC shaping circuit and a current commutation circuit. The pulsating DC shaping circuit generates a pulsating voltage according to the PWM signal and transmits it to the current commutation circuit. The current commutation circuit performs current commutation on the pulsating voltage at zero point to output a high-voltage DC voltage and delivers the high-voltage DC voltage to drive the SPD diaphragm.

[0061] like Figure 9 As shown, Figure 9This is the circuit schematic of a pulsating DC shaping circuit, whose V_150V interface is connected to the V_150V interface of the BOOST boost circuit. The circuit consists of a gate driver U10 (AUIRS2301) and high-voltage MOSFETs Q6 and Q7. Pins 12_H and 12_L of the gate driver U10 are connected to the corresponding pins of the high-voltage MCU to receive PWM signals from the MCU. The gate driver U10 controls MOSFETs Q6 and Q7 to alternately conduct according to the PWM signal, generating a pulsating voltage. After passing through an LC filter circuit composed of L6, L7, L8, and C91 (the LC filter circuit is used to filter out the PWM switching frequency (e.g., 20kHz) and its harmonics), a smooth pulsating DC current is output. Figure 10 The current commutation circuit.

[0062] like Figure 10 As shown, Figure 10 This is the circuit schematic of the current commutation circuit. The circuit consists of two half-bridge circuits, which are controlled by chips U12 and U13 respectively. Both of their H_12V_D interfaces are connected to the H_12V_D interface of the pulsating DC shaping circuit. The HIN and LIN pins of chips U12 and U13 are connected to the 12_H and 12_L pins of the high-voltage MCU to receive PWM signals from the high-voltage MCU. The V_AC interface of the pulsating DC shaping circuit is connected to the two V_AC interfaces of the current commutation circuit to receive the pulsating DC output from the pulsating DC shaping circuit. Chips U12 and U13 control MOSFETs Q8 and Q11 according to the PWM signal. MOSFETs Q19 and Q11 are periodically turned on alternately, causing the pulsating DC current to be reversed. After the current is reversed, the two pulsating DC currents are filtered by their respective LC filters (L9 and C4, L10 and C101) and then output from the CH pin and COM pin of the connector to form a complete power frequency sinusoidal AC voltage.

[0063] Preferably, the output terminal of the current commutation circuit is also connected to an LC filter circuit, which is used to filter out the switching frequency harmonics in the power frequency sinusoidal AC voltage to obtain a sinusoidal voltage with low distortion.

[0064] Preferably, the output port of the current commutation circuit is also connected to an output detection circuit. The output detection circuit is used to acquire the high-voltage AC voltage supplied to the SPD diaphragm in real time and transmit the acquired voltage value to the high-voltage MCU. Specifically, if the output terminal of the current commutation circuit is connected to an LC filter circuit, the sampling resistor of the output detection circuit is connected in series between the output terminal of the LC filter circuit and the SPD diaphragm; if the output terminal of the current commutation circuit is directly connected to the SPD diaphragm, the output detection circuit is connected in series between the current commutation circuit and the SPD diaphragm.

[0065] The output detection circuit includes a sampling resistor connected in series in the output loop of the current commutation circuit, and an operational amplifier circuit for multi-stage amplification of the acquired output voltage.

[0066] like Figure 11 As shown, Figure 11 This is the circuit schematic for the output detection circuit. A sampling resistor R_sense is connected in series between the output of the LC filter circuit and the SPD diaphragm, or in series between the current commutation circuit and the SPD diaphragm, to acquire the magnitude of the sinusoidal AC voltage supplied to the SPD diaphragm. The voltage difference across the sampling resistor R_sense is amplified by a first-stage differential amplifier centered on operational amplifier U11A, and then enters a non-inverting amplifier centered on operational amplifier U11B for secondary amplification and conditioning of the sinusoidal AC voltage, converting it into a voltage signal CH_I_FB suitable for sampling by the MCU ADC, so that it can be input into the high-voltage MCU.

[0067] Preferably, the high-voltage zone circuit further includes an NTC temperature detection circuit, which is used to detect the canopy temperature or the temperature of key components in real time and transmit the collected temperature data to the high-voltage MCU. Figure 7 As shown, the temperature sensor attached to the SPD film or other power devices of the canopy filters its detection signal through a filter network composed of R19 and C34, and then inputs it to the high-voltage MCU from the ANI15 pin of the high-voltage MCU to realize over-temperature protection and temperature compensation.

[0068] This invention also provides a control method for an SPD dimming canopy controller, specifically including the following steps: After the S1 SPD dimming canopy controller is powered on, the low-voltage MCU and the high-voltage MCU are initialized respectively, including peripheral configuration, parameter loading, self-test, etc.

[0069] The low-voltage MCU continuously monitors the network via the LIN bus. When it receives a dimming command (such as "set the light transmittance to 50%) from the body controller or manual switch through the vehicle network, the low-voltage MCU parses and verifies the command.

[0070] S2, the low-voltage MCU sends the dimming command to the primary side of the digital isolator. After isolating the signal, the digital isolator sends it to the UART serial port of the high-voltage MCU.

[0071] S3, the high-voltage MCU parses the dimming command it receives, looks up the transmittance-voltage mapping table stored in its internal storage, or converts the dimming command into the target AC voltage effective value according to the calculation model. For example, it maps "50% transmittance" to the corresponding "target AC voltage effective value V_target" (for example, 70Vrms).

[0072] S4, the high-voltage MCU acquires the actual output voltage feedback value collected by the output detection circuit in real time, and dynamically adjusts the duty cycle of its output PWM signal according to the deviation between the effective value of the target AC voltage and the actual output voltage feedback value through a closed-loop control algorithm.

[0073] S5, the PWM signal drives the half-bridge inverter circuit to work, so that the effective value of the AC voltage finally output to the canopy (SPD film) is stabilized at the target value, thereby achieving precise control of the light transmittance of the SPD dimming canopy.

[0074] By adjusting the duty cycle of the PWM signal output by the high-voltage MCU, the effective value of the AC voltage finally output to the canopy can be precisely controlled. When the actual output voltage is less than the target effective value of the AC voltage, the duty cycle of the PWM signal output by the high-voltage MCU needs to be increased to improve the effective value of the AC voltage finally output to the canopy. Conversely, the duty cycle of the PWM signal output by the high-voltage MCU should be decreased.

[0075] Throughout the operation, the high-voltage MCU continuously monitors the canopy temperature or the temperature of critical components, as well as the high-voltage AC voltage supplied to the SPD diaphragm. If any parameter exceeds a safety threshold, the high-voltage MCU immediately executes protection procedures, such as shutting down the PWM output to stop the half-bridge inverter circuit; simultaneously, it sends a fault code to the low-voltage MCU U2 via the digital isolator U4. Upon receiving this code, the low-voltage MCU U2 can report the fault to the entire vehicle via the LIN bus and may control indicator lights to illuminate.

[0076] It should be understood that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A SPD dimming canopy controller, characterized in that, This includes low-voltage circuitry, high-voltage circuitry, and high-low voltage isolation circuitry connecting the low-voltage circuitry and the high-voltage circuitry. The power supply ports of the low-voltage zone circuit are connected to the vehicle battery and the high-low voltage isolation circuit respectively. The LIN communication interface is connected to the LNG bus transceiver through the LIN bus. The low-voltage zone circuit is used to receive dimming commands from the vehicle network through the LNG bus transceiver and transmit the dimming commands to the high-low voltage isolation circuit, and to supply power to the high-low voltage isolation circuit. The high-low voltage isolation circuit is used to transmit dimming commands to the high-voltage circuit and to supply the low-voltage voltage to the high-voltage circuit. The high-voltage circuit is used to invert the high-voltage DC voltage into the high-voltage AC voltage required to drive the SPD film according to the received dimming command.

2. The SPD dimming canopy controller according to claim 1, characterized in that, The high and low voltage isolation circuit includes a digital isolator and a flyback isolation power supply. The low-voltage side UART serial port of the digital isolator is connected to the UART serial port of the low-voltage MCU in the low-voltage zone circuit, and the high-voltage side UART serial port of the digital isolator is connected to the UART serial port of the high-voltage MCU in the high-voltage zone circuit. The digital isolator is used to transmit the dimming command it receives to the high-voltage MCU in the high-voltage zone circuit and to supply power to the high-voltage MCU. The flyback isolation power supply has its first power supply terminal connected to the low-voltage circuit and its second power supply terminal connected to the high-voltage circuit. The flyback isolation power supply is used to transmit the DC voltage from the low-voltage region to the high-voltage region.

3. The SPD dimming curtain controller of claim 2, wherein, The low-voltage circuit includes a low-voltage power supply circuit, a LIN communication interface circuit, and a low-voltage MCU. The first power port of the low-voltage power supply circuit is connected to the vehicle battery, the second power port is connected to the first power port of the LIN communication interface circuit, and the third power port is connected to the flyback isolation power supply. The low-voltage power supply circuit is used to convert the vehicle voltage of the vehicle battery into the first DC voltage to supply the LIN communication interface circuit and the flyback isolation power supply. The second power supply port of the LIN communication interface circuit is connected to the low-voltage MCU. The LIN communication interface of the LIN communication interface circuit is connected to the LIN bus. The UART serial port of the LIN communication interface circuit is connected to the UART serial port of the low-voltage MCU. The LIN communication interface circuit is used to transmit the dimming command received from the vehicle network to the digital isolator and convert the first DC voltage into the second DC voltage to supply the low-voltage MCU.

4. The SPD dimming curtain controller of claim 2, wherein, The high-voltage circuit includes a high-voltage MCU, a BOOST boost circuit, and a half-bridge inverter circuit. The high-voltage MCU is used to generate a PWM signal to control the half-bridge inverter circuit according to the received dimming command. The PWM signal output terminal of the high-voltage MCU is connected to the PWM signal input terminal of the half-bridge inverter circuit. The BOOST boost circuit is used to boost the first DC voltage to a high voltage DC voltage and supply it to the half-bridge inverter circuit; The half-bridge inverter circuit is used to invert the high-voltage DC voltage into the high-voltage AC voltage required to drive the SPD diaphragm according to the PWM signal.

5. The SPD dimming curtain controller of claim 4, wherein, The high-voltage zone circuit also includes an output detection circuit, which is used to collect the high-voltage AC voltage supplied to the SPD diaphragm in real time and send the collected voltage value to the high-voltage MCU.

6. The SPD light-curtain controller of claim 5, wherein, The output detection circuit includes a sampling resistor connected in series in the output loop of the current commutation circuit and an operational amplifier circuit for multi-stage amplification of the acquired output voltage.

7. The SPD light-curtain controller of claim 5, wherein, The high-voltage circuit also includes an NTC temperature detection circuit, which is used to detect the temperature of the canopy or key components in real time and transmit the collected temperature data to the high-voltage MCU.

8. The SPD light-curtain controller of claim 4, wherein, The output of the half-bridge inverter circuit is also connected to an LC filter circuit for filtering out switching frequency harmonics.

9. The SPD light-curtain controller of claim 2, wherein, The half-bridge inverter circuit includes a pulsating DC shaping circuit and a current commutation circuit. The pulsating DC shaping circuit generates a pulsating voltage according to the PWM signal and transmits it to the current commutation circuit. The current commutation circuit performs current commutation on the pulsating voltage at zero point to output a high-voltage DC voltage and delivers the high-voltage DC voltage to the drive SPD diaphragm.

10. A method of controlling an SPD dimming sky controller according to any one of claims 1 to 9, characterized in that, Specifically, the following steps are included: S1, the low-voltage MCU receives dimming commands from the body controller or manual switch through the vehicle network; S2, the low-voltage MCU sends the dimming command to the high-voltage MCU through the digital isolator; S3, the high-voltage MCU determines the corresponding effective value of the target AC voltage according to the dimming command; S4, the high-voltage MCU acquires the actual output voltage feedback value collected by the output detection circuit in real time, and dynamically adjusts the duty cycle of its output PWM signal according to the deviation between the effective value of the target AC voltage and the actual output voltage feedback value through a closed-loop control algorithm. S5, the PWM signal drives the half-bridge inverter circuit to work, so that the effective value of the AC voltage finally output to the canopy is stabilized at the target value, thereby realizing precise control of the light transmittance of the SPD dimming canopy.

11. The control method according to claim 10, characterized by, In step S3, the high-voltage MCU looks up the transmittance-voltage mapping table stored in its internal memory or converts the dimming command into the effective value of the target AC voltage according to the calculation model.

12. The control method according to claim 10, characterized by, It also includes step S6, where the output detection circuit collects the high-voltage AC voltage supplied to the SPD diaphragm in real time and feeds back the collected voltage value to the high-voltage MCU, and / or the NTC temperature detection circuit detects the canopy temperature or the temperature of key components in real time and feeds back the collected temperature data to the high-voltage MCU. When the voltage and / or temperature exceed the set threshold, the high-voltage MCU issues an alarm and protection command.

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