A power-on / off control circuit for a battery-powered electric aircraft propulsion system

Abstract

This invention discloses a power-on / off control circuit for a battery-powered electric aircraft propulsion system, comprising: an input high-voltage detection circuit, a signal isolation and drive circuit, a low-voltage receiving delay circuit, a low-voltage detection and drive circuit, and an output isolation drive circuit. The input high-voltage detection circuit includes a comparator U1, resistors R1, R2, and R5. The signal isolation and drive circuit includes resistors R3 and R4, a transistor Q1, an optocoupler U2, and a resistor R6. The output isolation drive circuit includes a relay. Through this method, the power-on / off control circuit for a battery-powered electric aircraft propulsion system of this invention performs power-on / off control through a purely hardware circuit, exhibiting high reliability and stability. It realizes automatic power-on / off logic and timing control of the electric aircraft propulsion system, independent of software operation.

Description

Technical Field

[0001] This invention relates to the field of power-on / off control technology for electric aircraft power systems, and in particular to a power-on / off control circuit for a battery-powered electric aircraft power system. Background Technology

[0002] The power system of a vertical takeoff and landing (VTOL) electric aircraft typically consists of a high-voltage battery pack, a power distribution unit, a motor driver, an electric motor, and a lift propeller. Proper power-on / off logic control and implementation are crucial for the safe and stable operation of the electric aircraft. One key technical aspect is the coordination between the motor driver and the opening and closing of the high-voltage battery pack for power-on / off control.

[0003] The high-voltage DC input terminal of a motor driver typically has a filter capacitor of several hundred to several thousand microfarads connected in parallel to provide the high-frequency ripple current required for driver operation. Its power-on process is a typical capacitive load charging process, which is divided into two stages: pre-charging and main relay closing.

[0004] The pre-charge circuit can consist of a pre-charge relay and a current-limiting resistor connected in series between the high-voltage battery pack output and the motor driver input, with the main relay connected in parallel with the pre-charge circuit. The pre-charge process is initiated by the closing of the driver input control signal K+ / K-, which activates the pre-charge relay. The high-voltage battery pack output charges the driver's input capacitor through the pre-charge relay and the current-limiting resistor, preventing inrush current during capacitor charging. When the difference between the capacitor voltage and the high voltage output of the battery pack falls below a certain limit, the main relay activates, providing the necessary low-resistance, high-current path for normal driver operation.

[0005] The pre-charge circuit's activation is entirely controlled by the state of the motor driver input signals K+ / K-, regardless of whether the battery pack actually has a high-voltage output. The main relay only detects the voltage difference between its two ends; it automatically closes when the voltage difference is less than a threshold. Once the main relay closes, a low-resistance path is formed from the battery pack output to the motor driver input. If the contactor inside the battery pack closes at this time, a huge surge current (hundreds of amperes) will rapidly charge the capacitor in the motor driver through the contactor, easily causing damage to the contactor and other series circuit components within the battery pack.

[0006] Therefore, the closing of the motor driver input signal (Event A) and the closing of the contactor within the battery pack (Event B) have strict timing requirements. Event A must follow Event B with an appropriate delay. When the battery pack high voltage is de-energized (the contactor within the battery pack opens), the motor driver input signal (K+ / K-) also needs to automatically open after a certain delay to set the correct initial conditions for the next high voltage energization. Existing electric aircraft power systems rely heavily on microcontrollers and software for power-on / off control, resulting in high standby power consumption and susceptibility to high-frequency interference signals, necessitating improvements. Summary of the Invention

[0007] The main technical problem solved by this invention is to provide a power-on / off control circuit for a battery-powered electric aircraft power system, which realizes the power-on / off control of the power system through hardware circuitry and reduces standby power consumption.

[0008] To solve the above-mentioned technical problems, the present invention provides a power-on / off control circuit for a battery-powered electric aircraft power system, comprising: an input high-voltage detection circuit, a signal isolation and drive circuit, a low-voltage receiving delay circuit, a low-voltage detection and drive circuit, and an output isolation drive circuit. The input high-voltage detection circuit includes a comparator U1, resistors R1, R2, and R5. Resistor R1 is connected between the negative terminal of the high-voltage battery pack and the non-inverting input of comparator U1. Resistor R2 is connected between the positive terminal of the high-voltage battery pack and the non-inverting input of comparator U1. The inverting input of comparator U1 is connected to a primary-side reference voltage Vref_P. The negative power supply port of comparator U1 is connected to the negative terminal of the high-voltage battery pack. The signal isolation and drive circuit... The isolation and drive circuit includes resistors R3 and R4, transistor Q1, optocoupler U2, and resistor R6. The positive power supply port of comparator U1 is connected to a primary-side auxiliary power supply voltage Vaux_P. Resistor R5 is connected between the primary-side auxiliary power supply voltage Vaux_P and the output terminal of comparator U1. Resistor R6 is connected between the primary-side auxiliary power supply voltage Vaux_P and the anode of the input diode of optocoupler U2. Resistor R3 is connected between the output terminal of comparator U1 and the base of transistor Q1. Resistor R4 is connected between the base of transistor Q1 and the negative terminal of the high-voltage battery pack. The emitter of transistor Q1 is connected to the negative terminal of the high-voltage battery pack. The collector of transistor Q1 is connected to the cathode of the input diode of optocoupler U2. The low-voltage receiving delay circuit includes resistor R7, diode D1, resistor R8, and capacitor C1. The low-voltage detection and driving circuit includes comparator U3, resistors R9, R10, R11, R12, and R13, transistor Q2, and transistor Q3. The output isolation driving circuit includes a relay. The positive power supply port of comparator U3 is connected to a secondary auxiliary power supply voltage Vaux_S. Resistor R7 is connected between the collector of the transistor at the output terminal of optocoupler U2 and the secondary auxiliary power supply voltage Vaux_S. The inverting input of comparator U3 is connected to a secondary reference voltage Vref_S. Diode D1 is connected between the emitter of the transistor at the output terminal of optocoupler U2 and the non-inverting input of comparator U3. Between the terminals, resistor R8 and capacitor C1 are connected in parallel between the non-inverting terminal of comparator U3 and the ground line; resistor R11 is connected between the output terminal of comparator U3 and the secondary auxiliary power supply voltage Vaux_S; resistor R12 is connected between the base of transistor Q3 and the secondary auxiliary power supply voltage Vaux_S; the emitter of transistor Q3 is connected to the secondary auxiliary power supply voltage Vaux_S; the relay is connected between the collector of transistor Q3 and the ground line; resistor R10 is connected between the output terminal of comparator U3 and the base of transistor Q2; resistor R13 is connected between the collector of transistor Q2 and the base of transistor Q3; and resistor R9 is connected between the base of transistor Q2 and the ground line.

[0009] In a preferred embodiment of the present invention, transistors Q1 and Q2 are NPN transistors.

[0010] In a preferred embodiment of the present invention, the transistor Q3 is a PNP transistor.

[0011] In a preferred embodiment of the present invention, the output isolation drive circuit further includes a diode D2, which is connected between the collector of transistor Q3 and the ground line.

[0012] In a preferred embodiment of the present invention, the input high voltage of the high voltage battery pack input circuit is HV+ / HV-. After HV+ / HV- is divided by resistors R1 and R2, the voltage sent to the non-inverting terminal of comparator U1 is HVIN. When HVIN < primary side reference voltage Vref_P, the output HV_EN of comparator U1 is low, transistor Q1 is turned off, and no current flows through the primary side of optocoupler U2.

[0013] When HVIN > primary reference voltage Vref_P, the output HV_EN of comparator U1 is high. After voltage division by resistors R3 and R4, transistor Q1 is turned on, and current flows through the primary side of optocoupler U2.

[0014] In a preferred embodiment of the present invention, the final voltage across capacitor C1 is VS. When VS > secondary auxiliary power supply voltage Vaux_S, comparator U3 outputs high. After voltage division by resistors R9 and R10, transistor Q2 is driven to turn on, and the base of transistor Q3 is pulled down, causing transistor Q3 to turn on. The secondary auxiliary power supply voltage Vaux_S supplies power to relay Relay through the emitter and collector of transistor Q3. The relay Relay contacts close, providing a start signal to the motor driver.

[0015] When the input high voltage is applied, HV+ / HV- < primary reference voltage Vref_P, comparator U1 flips, transistor Q1 turns off, no current flows through the primary side of optocoupler U2, and the secondary current also drops to 0. The voltage on capacitor C1 discharges through resistor R8.

[0016] When VS < secondary reference voltage Vref_S, comparator U3 flips, outputs low, transistor Q2 turns off, transistor Q3 base is pulled up and turned off, the power supply to the relay coil is cut off, diode D2 provides coil current freewheeling at the moment of power cut-off, preventing instantaneous high voltage caused by no freewheeling circuit from damaging transistor Q3.

[0017] The beneficial effects of this invention are as follows: The power-on / off control circuit for a battery-powered electric aircraft propulsion system disclosed in this invention performs power-on / off control through a purely hardware circuit, resulting in high reliability and stability. It realizes automatic power-on / off logic and timing control of the electric aircraft propulsion system, which is beneficial to the safe and reliable drive of the high-voltage system and low-voltage control circuit. Furthermore, the power-on and power-off delays can be set through hardware parameters, and different capacity filter capacitors can be matched to suit different types of motor drivers. It does not rely on software operation, requires no microcontroller, does not generate high-frequency interference signals, and has extremely low standby power consumption, which can be ignored. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of 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, wherein:

[0019] Figure 1 This is a system power distribution block diagram of a battery-powered electric aircraft propulsion system according to the present invention;

[0020] Figure 2 This invention relates to a power-on / off control circuit for a battery-powered electric aircraft propulsion system.

[0021] The circuit structure diagram is shown. Detailed Implementation

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Please see Figures 1-2 The embodiments of the present invention include:

[0024] like Figure 1 As shown, the electric aircraft power system:

[0025] A normal power-on procedure is as follows:

[0026] The contactor inside the high-voltage battery pack closes → the battery pack outputs high voltage → the motor driver control terminal (K+ / K-) closes → the pre-charging circuit operates → the capacitor inside the motor driver is fully charged → the main relay closes → a low-resistance path is formed.

[0027] A normal power-down procedure is as follows:

[0028] The contactor inside the high-voltage battery pack opens → the high-voltage output of the battery pack closes → the capacitor of the motor driver discharges and releases energy → the control terminal (K+ / K-) of the motor driver opens → the motor driver closes.

[0029] like Figure 2 The power-on / off control circuit, i.e., the power-on / off control logic, of the battery-powered electric aircraft propulsion system shown is connected to... Figure 1 The high-voltage battery pack and motor driver shown are connected via an input high-voltage detection circuit, a signal isolation and drive circuit, a low-voltage receiving delay circuit, a low-voltage detection and drive circuit, and an output isolation drive circuit. In this embodiment, the input high-voltage detection circuit includes a comparator U1, resistors R1, R2, and R5. Resistor R1 is connected between the negative terminal of the high-voltage battery pack and the non-inverting input of comparator U1, and resistor R2 is connected between the positive terminal of the high-voltage battery pack and the non-inverting input of comparator U1 to perform voltage division. The inverting input of comparator U1 is connected to a primary-side reference voltage Vref_P, and the negative power supply port of comparator U1 is connected to the negative terminal of the high-voltage battery pack.

[0030] The signal isolation and driving circuit includes resistors R3 and R4, transistor Q1, optocoupler U2, and resistor R6. The positive power supply port of comparator U1 is connected to a primary-side auxiliary power supply voltage Vaux_P. Resistor R3 is connected between the output of comparator U1 and the base of transistor Q1. Resistor R5 is connected between the primary-side auxiliary power supply voltage Vaux_P and the output of comparator U1. Resistor R6 is connected between the primary-side auxiliary power supply voltage Vaux_P and the anode of the input diode of optocoupler U2. In this embodiment, transistor Q1 is an NPN transistor. Resistor R4 is connected between the base of transistor Q1 and the negative terminal of the high-voltage battery pack for voltage division. The emitter of transistor Q1 is connected to the negative terminal of the high-voltage battery pack, and the collector of transistor Q1 is connected to the cathode of the input diode of optocoupler U2.

[0031] The low-voltage receiving delay circuit includes resistor R7, diode D1, resistor R8 and capacitor C1. The low-voltage detection and driving circuit includes comparator U3, resistor R9, resistor R10, resistor R11, resistor R12, resistor R13, transistor Q2 and transistor Q3. In this embodiment, transistor Q2 is an NPN transistor and transistor Q3 is a PNP transistor.

[0032] The positive power supply port of comparator U3 is connected to a secondary auxiliary power supply voltage Vaux_S. Resistor R7 is connected between the collector of the transistor at the output terminal of optocoupler U2 and the secondary auxiliary power supply voltage Vaux_S. The inverting input of comparator U3 is connected to a secondary reference voltage Vref_S. Diode D1 is connected between the emitter of the transistor at the output terminal of optocoupler U2 and the non-inverting input of comparator U3. Resistor R8 and capacitor C1 are connected in parallel between the non-inverting input of comparator U3 and ground. Resistor R11 is connected between the output terminal of comparator U3 and the secondary auxiliary power supply voltage Vaux_S. Resistor R12 is connected between the base of transistor Q3 and the secondary auxiliary power supply voltage Vaux_S. The emitter of transistor Q3 is connected to the secondary auxiliary power supply voltage Vaux_S. Resistor R10 is connected between the output terminal of comparator U3 and the base of transistor Q2. Resistor R13 is connected between the collector of transistor Q2 and the base of transistor Q3. Resistor R9 is connected between the base of transistor Q2 and ground to perform voltage division.

[0033] The output isolation drive circuit includes a relay (Relay) and a diode (D2). The relay (Relay) is connected between the collector of transistor Q3 and the ground line, and the diode (D2) is connected between the collector of transistor Q3 and the ground line, improving safety during use.

[0034] The high voltage input of the high voltage battery pack input circuit is HV+ / HV-. After HV+ / HV- is divided by resistors R1 and R2, the voltage sent to the non-inverting input of comparator U1 is HVIN. When HVIN < primary side reference voltage Vref_P (set threshold), the output HV_EN of comparator U1 is low, transistor Q1 is turned off, and no current flows through the primary side of optocoupler U2.

[0035] When HVIN > primary reference voltage Vref_P, the output HV_EN of comparator U1 is high. After voltage division by resistors R3 and R4, transistor Q1 is turned on, and current flows through the primary side of optocoupler U2. The magnitude of the current is determined by the primary auxiliary power supply voltage Vaux_P and the resistance value of resistor R6.

[0036] The primary current of optocoupler U2 is amplified (the theoretical upper limit of the secondary current is determined by the optocoupler's amplification factor CTR) and then flows through the secondary transistor of the optocoupler. The actual secondary current is determined by the R / C circuit composed of resistor R7, resistor R8, and capacitor C1, which also determines the startup delay of the secondary circuit.

[0037] The final voltage across capacitor C1 is VS. VS is related to the voltage division ratio of resistor R7 / R8 and the secondary auxiliary power supply voltage Vaux_S. The charging time is related to the values ​​of resistor R7 and capacitor C1. The larger the values ​​of resistor R7 and capacitor C1, the longer the charging time.

[0038] When VS > secondary auxiliary power supply voltage Vaux_S, comparator U3 outputs high. After voltage division by resistors R9 and R10, it drives transistor Q2 to turn on and pulls down the base of transistor Q3, causing transistor Q3 to turn on. The secondary auxiliary power supply voltage Vaux_S supplies power to relay Relay through the emitter and collector of transistor Q3. The relay Relay contacts close, providing a start signal to the motor driver.

[0039] When the input high voltage is applied, HV+ / HV- < primary side reference voltage Vref_P, comparator U1 flips, transistor Q1 is turned off, no current flows through the primary side of optocoupler U2, and the secondary side current also drops to 0. The voltage on capacitor C1 is discharged through resistor R8, and the discharge delay is determined by the values ​​of resistor R8 and capacitor C1.

[0040] When VS < secondary reference voltage Vref_S, comparator U3 flips, outputs low, transistor Q2 turns off, transistor Q3 base is pulled up and turned off, the power supply to the relay coil is cut off, diode D2 provides coil current freewheeling at the moment of power cut-off, preventing instantaneous high voltage caused by no freewheeling circuit from damaging transistor Q3.

[0041] In summary, the power-on / off control circuit for a battery-powered electric aircraft propulsion system disclosed in this invention controls power-on / off through a purely hardware circuit, without relying on software operation, requiring no microcontroller, and generating no high-frequency interference signals. Therefore, it has high reliability and stability, and low standby power consumption.

[0042] The above are merely embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A power-on / off control circuit for a battery-powered electric aircraft propulsion system, connected between a high-voltage battery pack and a motor driver, characterized in that, include: The system includes an input high-voltage detection circuit, a signal isolation and drive circuit, a low-voltage receiving delay circuit, a low-voltage detection and drive circuit, and an output isolation drive circuit. The input high-voltage detection circuit includes a comparator U1, resistors R1, R2, and R5. Resistor R1 is connected between the negative terminal of the high-voltage battery pack and the non-inverting input of comparator U1. Resistor R2 is connected between the positive terminal of the high-voltage battery pack and the non-inverting input of comparator U1. The inverting input of comparator U1 is connected to a primary-side reference voltage Vref_P. The negative power supply port of comparator U1 is connected to the negative terminal of the high-voltage battery pack. The signal isolation and drive circuit includes resistors R3 and R4, a transistor Q1, an optocoupler U2, and a resistor R6. The comparator... The positive power supply port of U1 is connected to a primary-side auxiliary power supply voltage Vaux_P. Resistor R5 is connected between the primary-side auxiliary power supply voltage Vaux_P and the output terminal of comparator U1. Resistor R6 is connected between the primary-side auxiliary power supply voltage Vaux_P and the anode of the input diode of optocoupler U2. Resistor R3 is connected between the output terminal of comparator U1 and the base of transistor Q1. Resistor R4 is connected between the base of transistor Q1 and the negative terminal of the high-voltage battery pack. The emitter of transistor Q1 is connected to the negative terminal of the high-voltage battery pack. The collector of transistor Q1 is connected to the cathode of the input diode of optocoupler U2. The low-voltage receiving delay circuit includes resistor R7, diode D1, and resistor... The low-voltage detection and driving circuit includes comparator U3, resistors R9, R10, R11, R12, R13, transistors Q2 and Q3, and the output isolation driving circuit includes a relay. The positive power supply port of comparator U3 is connected to a secondary auxiliary power supply voltage Vaux_S. Resistor R7 is connected between the collector of the transistor at the output terminal of optocoupler U2 and the secondary auxiliary power supply voltage Vaux_S. The inverting input of comparator U3 is connected to a secondary reference voltage Vref_S. Diode D1 is connected between the emitter of the transistor at the output terminal of optocoupler U2 and the non-inverting input of comparator U3. Resistor R8 and capacitor C1...

1. Resistor R11 is connected in parallel between the non-inverting input of comparator U3 and the ground wire. Resistor R12 is connected between the base of transistor Q3 and the secondary auxiliary power supply voltage Vaux_S. The emitter of transistor Q3 is connected to the secondary auxiliary power supply voltage Vaux_S. Relay is connected between the collector of transistor Q3 and the ground wire. Resistor R10 is connected between the output of comparator U3 and the base of transistor Q2. Resistor R13 is connected between the collector of transistor Q2 and the base of transistor Q3. Resistor R9 is connected between the base of transistor Q2 and the ground wire.

2. The power-on / off control circuit for a battery-powered electric aircraft propulsion system according to claim 1, characterized in that, The transistors Q1 and Q2 are NPN transistors.

3. The power-on / off control circuit for a battery-powered electric aircraft propulsion system according to claim 1, characterized in that, The transistor Q3 is a PNP transistor.

4. The power-on / off control circuit for a battery-powered electric aircraft propulsion system according to claim 1, characterized in that, The output isolation drive circuit also includes a diode D2, which is connected between the collector of transistor Q3 and the ground line.

5. The power-on / off control circuit for a battery-powered electric aircraft propulsion system according to claim 1, characterized in that, The high voltage input of the high voltage battery pack input circuit is HV+ / HV-. After HV+ / HV- is divided by resistors R1 and R2, the voltage sent to the non-inverting terminal of comparator U1 is HVIN. When HVIN < primary reference voltage Vref_P, the output HV_EN of comparator U1 is low, transistor Q1 is turned off, and no current flows through the primary side of optocoupler U2. When HVIN > primary reference voltage Vref_P, the output HV_EN of comparator U1 is high. After voltage division by resistors R3 and R4, transistor Q1 is turned on, and current flows through the primary side of optocoupler U2.

6. The power-on / off control circuit for a battery-powered electric aircraft propulsion system according to claim 4, characterized in that, The final voltage across capacitor C1 is VS. When VS > secondary auxiliary power supply voltage Vaux_S, comparator U3 outputs high. After voltage division by resistors R9 and R10, transistor Q2 is turned on, and the base of transistor Q3 is pulled down, causing transistor Q3 to turn on. The secondary auxiliary power supply voltage Vaux_S supplies power to relay Relay through the emitter and collector of transistor Q3. The relay Relay contacts close, providing a start signal to the motor driver. When the input high voltage is applied, HV+ / HV- < primary reference voltage Vref_P, comparator U1 flips, transistor Q1 turns off, no current flows through the primary side of optocoupler U2, and the secondary current also drops to 0. The voltage on capacitor C1 discharges through resistor R8. When VS < secondary reference voltage Vref_S, comparator U3 flips, outputs low, transistor Q2 turns off, transistor Q3 base is pulled up and turned off, the power supply to the relay coil is cut off, diode D2 provides coil current freewheeling at the moment of power cut-off, preventing instantaneous high voltage caused by no freewheeling circuit from damaging transistor Q3.

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