Electric propulsion system high-voltage electrical interconnection structure and interconnection method based on airworthiness requirements

Abstract

The invention belongs to the technical field of electric propulsion systems, and particularly discloses an electric propulsion system high-voltage electrical interconnection structure based on airworthiness requirements and an interconnection method.The high-voltage electrical interconnection structure comprises a lithium battery pack, a motor controller, a connector X1, a first contactor K1, a second contactor K2, a pre-charging resistor R1, a driving relay J1 and a switch S1, the lithium battery pack is used for realizing high-voltage interconnection with the motor controller through the connector X1 and the second contactor K2, and a soft start circuit composed of the first contactor K1 and the pre-charging resistor R1 can pre-charge a support capacitor in the motor controller before a high-voltage main circuit is switched on, so that the generation of an electric arc at the moment of high-voltage power-on is prevented; a secondary drive circuit composed of the drive relay J1 and the switch S1 can control the second contactor K2 to be switched on. The high-voltage electrical interconnection structure and the interconnection method have the advantages that the structure is reasonable, and the generation of electric arc at the high-voltage power-on moment can be prevented.

Description

Technical Field

[0001] The present invention relates to the technical field of electric propulsion systems, and particularly provides a high-voltage electrical interconnection structure and an interconnection method for an electric propulsion system based on airworthiness requirements. Background Art

[0002] As the power source of an electric aircraft, the electric propulsion system is directly related to flight safety. Therefore, extremely high requirements are imposed on the reliability and safety of the electric propulsion system. The aviation electric propulsion system is powered by high-voltage direct current. In the high-voltage wire interconnection structure, due to the existence of support capacitors inside the motor controller, current spikes several times or even dozens of times will be generated at the moment of power-on, resulting in arcing of the contactor between the lithium battery pack and the motor controller at the moment when the high-voltage direct current power supply is connected to the on-board power grid, triggering faults in the electric propulsion system and causing harmful consequences.

[0003] To meet the airworthiness safety requirements of electric aircraft, in the "Guidelines for Compiling Special Conditions for Electric Propulsion Systems", it is required that "the high-voltage wire interconnection system should be able to prevent faults caused by arcing". Therefore, it has become an urgent problem to propose a new type of high-voltage wire interconnection structure that can meet the airworthiness requirements to avoid the generation of arcing at the moment of power-on. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a high-voltage electrical interconnection structure and an interconnection method for an electric propulsion system based on airworthiness requirements to solve the problem of arcing generated at the moment of power-on in the existing high-voltage electrical interconnection structure of the electric propulsion system based on airworthiness requirements.

[0005] On the one hand, the present invention provides a high-voltage electrical interconnection structure for an electric propulsion system based on airworthiness requirements, including: a lithium battery pack, a motor controller, a connector X1, a first contactor K1, a second contactor K2, a pre-charge resistor R1, a drive relay J1, and a switch S1. Among them, the negative electrode of the lithium battery pack is connected to the negative electrode of the motor controller, the positive electrode of the lithium battery pack is connected to the positive electrode of the motor controller through the connector X1 and the second contactor K2. The positive electrode of the coil of the second contactor K2 is connected to the positive electrode of the 28V DC power supply, the negative electrode of the coil of the second contactor K2 is grounded through the drive relay J1, the negative electrode of the coil of the drive relay J1 is grounded through the switch S1, and the positive electrode of the coil of the drive relay J1 is connected to the 28V low-voltage DC signal output terminal of the motor controller. The 28V low-voltage DC signal output terminal of the motor controller is used to output a 28V low-voltage DC signal when the high-voltage DC voltage across the support capacitor C1 inside it reaches a preset value. The coil of the first contactor K1 is connected to the 28V low-voltage DC power supply through the connector X1, and the first contactor K1 is connected in series with the pre-charge resistor R1 and is connected in parallel with the second contactor K2.

[0006] Preferably, the second contactor K2 is connected to the positive electrode of the lithium battery pack through a long-pin contact pair on the connector X1, and the coil of the first contactor K1 is connected to a low-voltage DC 28V power supply through two short-pin contact pairs on the connector X1.

[0007] The present invention also provides a high-voltage electrical interconnection method for an electric propulsion system based on airworthiness requirements. Using the above-mentioned high-voltage electrical interconnection structure for an electric propulsion system based on airworthiness requirements, it includes the following steps: S101: Connect the connector X1. At this time, the low-voltage DC 28V power supply supplies power to the coil of the first contactor K1, the contacts of the first contactor K1 are closed, and the high-voltage direct current provided by the lithium battery pack is connected to the motor controller through the first contactor K1 and the pre-charge resistor R1 to pre-charge the support capacitor C1. S201: Determine whether the high-voltage direct current voltage across the support capacitor C1 inside the motor controller reaches a preset value. If it reaches, the 28V low-voltage DC signal output terminal of the motor controller outputs a 28V low-voltage DC signal. S301: Close the switch S1. At this time, the negative pole of the coil of the drive relay J1 is grounded, the contacts of the drive relay J1 are closed. After the contacts are closed, the negative pole of the coil of the second contactor K2 is grounded, the contacts of the second contactor K2 are closed. At this time, the high-voltage direct current provided by the lithium battery pack is connected to the motor controller through the second contactor K2, and the circuit composed of the first contactor K1 and the pre-charge resistor R1 is bypassed, completing the high-voltage electrical interconnection.

[0008] Preferably, connecting the connector X1 includes: first connecting the long-pin contact pair for connecting the second contactor K2 and the lithium battery pack, and then connecting the short-pin contact pair for connecting the coil of the first contactor K1 and the low-voltage DC 28V power supply.

[0009] The high-voltage electrical interconnection structure and interconnection method for an electric propulsion system based on airworthiness requirements provided by the present invention can pre-charge the support capacitor inside the motor controller through the designed soft start circuit composed of the first contactor K1 and the pre-charge resistor R1, thereby preventing the generation of arcs during high-voltage power-on. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The following further describes the present invention in detail with reference to the drawings and embodiments: Figure 1 is a schematic structural diagram of the high-voltage electrical interconnection structure for an electric propulsion system based on airworthiness requirements provided by the present invention; Figure 2 is a flowchart of the high-voltage electrical interconnection method for an electric propulsion system based on airworthiness requirements provided by the present invention. Detailed implementation manners

[0011] The present invention will be further explained below in combination with specific implementation manners, but the present invention is not limited thereto.

[0012] As Figure 1 shown, the present invention provides a high-voltage electrical interconnection structure of an electric propulsion system based on airworthiness requirements, including: a lithium battery pack 1, a motor controller 2, a connector X1, a first contactor K1, a second contactor K2, a pre-charge resistor R1, a drive relay J1, and a switch S1. Among them, the negative electrode of the lithium battery pack 1 is connected to the negative electrode of the motor controller 2, and the positive electrode of the lithium battery pack 1 is connected to the positive electrode of the motor controller 2 through the connector X1 and the second contactor K2, for connecting the high-voltage direct current provided by the lithium battery pack 1 to the motor controller 2 through the second contactor K2. The positive electrode of the coil of the second contactor K2 is connected to the positive electrode of the 28V DC power supply, and the negative electrode of the coil of the second contactor K2 is grounded through the drive relay J1. The negative electrode of the coil of the drive relay J1 is grounded through the switch S1, and the positive electrode of the coil of the drive relay J1 is connected to the 28V low-voltage DC signal output terminal of the motor controller 2. The 28V low-voltage DC signal output terminal of the motor controller 2 is used to output a 28V low-voltage DC signal when the high-voltage direct current voltage across the internal support capacitor C1 reaches a preset value. Since the driving ability of the signal output by the motor controller 2 is weak, the present invention adopts a two-stage driving method to turn on the second contactor K2. The 28V low-voltage DC signal output by the motor controller 2 is used to supply power to the positive electrode of the coil of the drive relay J1. The coil of the first contactor K1 is connected to the 28V low-voltage DC power supply through the connector X1. The first contactor K1 is connected in series with the pre-charge resistor R1 and then connected in parallel with the second contactor K2. The 28V low-voltage DC power supply is used to supply power to the coil of the first contactor K1 after the connector X1 is connected. After the 28V low-voltage DC power supply supplies power to the coil of the first contactor K1, the high-voltage direct current provided by the lithium battery pack 1 is connected to the motor controller 2 through the first contactor K1 and the pre-charge resistor R1, for pre-charging the support capacitor C1. Due to the presence of the pre-charge resistor R1 in the circuit, the charging current can be adjusted within an allowable range, and current spikes during the connection process can be avoided.

[0013] As an improvement of the technical solution, the second contactor K2 is connected to the positive electrode of the lithium battery pack 1 through a long-pin contact pair on the connector X1, and the coil of the first contactor K1 is connected to the 28V low-voltage DC power supply through two short-pin contact pairs on the connector X1. This design can ensure that during the connection process of the connector X1, the long-pin contact pair for connecting the high-voltage DC line is connected first. At this time, the 28V low-voltage DC power supply is not connected to the first contactor K1, and the coil of the first contactor K1 is not powered. Therefore, the contacts of the first contactor K1 are not attracted, so there is no high voltage on the long-pin contact pair. Continuing to insert the contact pair, the two short-pin contact pairs are respectively connected. At this time, the contacts of the first contactor K1 are connected, and the high-voltage direct current is connected through the long-pin contact pair. The disconnection process of the connector X1 is the same. The first contactor K1 disconnects first, and then the long-pin contact pair of the connector X1 disconnects. This design can avoid plugging and unplugging the connector X1 with (high) voltage, and prevent arcing and sparking during the plugging and unplugging process of the connector X1.

[0014] As Figure 2 shown, the present invention also provides a high-voltage electrical interconnection method for an electric propulsion system based on airworthiness requirements. Using the above high-voltage wire interconnection structure, it includes the following steps: S101: Connect the connector X1. At this time, the 28V low-voltage DC power supply supplies power to the coil of the first contactor K1, the contacts of the first contactor K1 are connected, and the high-voltage direct current provided by the lithium battery pack 1 is connected to the motor controller 2 through the first contactor K1 and the pre-charge resistor R1 to pre-charge the support capacitor C1. S201: Determine whether the high-voltage DC voltage across the support capacitor C1 inside the motor controller 2 reaches a preset value (corresponding to the completion of charging). If it reaches, the 28V low-voltage DC signal output terminal of the motor controller 2 outputs a 28V low-voltage DC signal. Among them, determining whether it reaches the preset value can be achieved through the preset control logic inside the motor controller. S301: Connect the switch S1. At this time, the negative electrode of the coil of the drive relay J1 is grounded, the contacts of the drive relay J1 are connected. After the contacts are connected, the negative electrode of the coil of the second contactor K2 is grounded, the contacts of the second contactor K2 are connected. At this time, the high-voltage direct current provided by the lithium battery pack 1 is connected to the motor controller 2 through the second contactor K2, and the circuit composed of the first contactor K1 and the pre-charge resistor R1 is bypassed. Thus, the high-voltage electrical interconnection is completed.

[0015] As an improvement of the technical solution, connecting the connector X1 includes: first connecting the long-pin contact pair for connecting the second contactor K2 and the lithium battery pack 1, and then connecting the short-pin contact pair for connecting the coil of the first contactor K1 and the low-voltage DC 28V power supply. This design can avoid hot plugging (high voltage) the connector X1 and prevent arcing and sparking during the plugging and unplugging of the connector X1.

[0016] For the high-voltage electrical interconnection structure and interconnection method of the electric propulsion system based on airworthiness requirements, by designing a soft start circuit composed of a first contactor K1 and a pre-charge resistor R1, the support capacitor inside the motor controller can be pre-charged before the high-voltage main circuit is connected, thereby preventing the generation of arcs at the moment of high-voltage power-on.

[0017] The specific embodiments of the present invention are written in a progressive manner, emphasizing the differences between each embodiment, and the similar parts can be referred to each other.

[0018] The above has described the embodiments of the present invention in detail, but the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A high-voltage electrical interconnection structure for an electric propulsion system based on airworthiness requirements, characterized in that Comprising: A lithium battery pack, a motor controller, a connector X1, a first contactor K1, a second contactor K2, a pre-charge resistor R1, a drive relay J1, and a switch S1. Wherein, the negative electrode of the lithium battery pack is connected to the negative electrode of the motor controller, the positive electrode of the lithium battery pack is connected to the positive electrode of the motor controller via the connector X1 and the second contactor K2. The positive electrode of the coil of the second contactor K2 is connected to the positive electrode of the 28V DC power supply, the negative electrode of the coil of the second contactor K2 is grounded via the drive relay J1, the negative electrode of the coil of the drive relay J1 is grounded via the switch S1, and the positive electrode of the coil of the drive relay J1 is connected to the 28V low-voltage DC signal output terminal of the motor controller. The 28V low-voltage DC signal output terminal of the motor controller is used to output a 28V low-voltage DC signal when the high-voltage DC voltage across the support capacitor C1 inside it reaches a preset value. The coil of the first contactor K1 is connected to the 28V low-voltage DC power supply via the connector X1, and the first contactor K1 and the pre-charge resistor R1 are connected in series and then connected in parallel with the second contactor K2.

2. The high-voltage electrical interconnection structure of the electric propulsion system based on airworthiness requirements according to claim 1, wherein: The second contactor K2 is connected to the positive electrode of the lithium battery pack through a long-pin contact pair on the connector X1, and the coil of the first contactor K1 is connected to the 28V low-voltage DC power supply through two short-pin contact pairs on the connector X1.

3. A high-voltage electrical interconnection method for an electric propulsion system based on airworthiness requirements, characterized in that, Using the high-voltage electrical interconnection structure of the electric propulsion system based on airworthiness requirements described in claim 1 or 2, comprising the following steps: S101: Connect the connector X1. At this time, the 28V low-voltage DC power supply supplies power to the coil of the first contactor K1, the contacts of the first contactor K1 are closed, and the high-voltage DC power provided by the lithium battery pack is connected to the motor controller through the first contactor K1 and the pre-charge resistor R1 to pre-charge the support capacitor C1. S201: Determine whether the high-voltage DC voltage across the support capacitor C1 inside the motor controller reaches the preset value. If it reaches, the 28V low-voltage DC signal output terminal of the motor controller outputs a 28V low-voltage DC signal. S301: Close the switch S1. At this time, the negative electrode of the coil of the drive relay J1 is grounded, the contacts of the drive relay J1 are closed. After the contacts are closed, the negative electrode of the coil of the second contactor K2 is grounded, and the contacts of the second contactor K2 are closed. At this time, the high-voltage DC power provided by the lithium battery pack is connected to the motor controller through the second contactor K2, and the circuit composed of the first contactor K1 and the pre-charge resistor R1 is bypassed, completing the high-voltage electrical interconnection.

4. The high-voltage electrical interconnection method of the electric propulsion system based on airworthiness requirements according to claim 3, characterized in that Connecting the connector X1 includes: first connecting the long-pin contact pair for connecting the second contactor K2 and the lithium battery pack, and then connecting the short-pin contact pair for connecting the coil of the first contactor K1 and the 28V low-voltage DC power supply.

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