Highly reliable power supply circuit for hollow cathode neutralizer and method of operation thereof

Abstract

The application provides a high-reliability power supply circuit of a hollow cathode neutralizer and a working method thereof. The power supply circuit comprises an input filter capacitor, a touch pole power supply circuit and a heater power supply circuit. The input filter capacitor is used to provide a DC voltage source for the touch pole power supply circuit and the heater power supply circuit. The touch pole power supply circuit is used to perform first circuit processing on the DC voltage filtered by the input filter capacitor, so as to form a DC voltage of a touch pole load of the neutralizer. The heater power supply circuit is used to perform second circuit processing on the DC voltage filtered by the input filter capacitor, so as to form a DC voltage of a heater load of the neutralizer. The application can be used for radio frequency ion electric propulsion, can provide sufficient electrons at a touch pole ignition moment, and is not affected by the equivalent impedance of the touch pole in the idle state. The idle high-voltage output can be stable in the whole life cycle of the thruster, and the reliability of ignition success in the whole life cycle of the thruster is ensured.

Description

Technical Field

[0001] This invention belongs to the field of spacecraft radio frequency ion electric propulsion technology, specifically relating to a power supply circuit and its working method for a highly reliable hollow cathode neutralizer. Background Technology

[0002] Radio frequency (RF) ion electric propulsion technology, as a high-performance micro-electric propulsion technology, possesses advantages such as high specific impulse, plume collimation, simple structure, and ease of miniaturization, and has broad application prospects in the commercial microsatellite field. The RF ion electric propulsion system consists of an RF ion thruster, a neutralizer, a power processing and control unit, an RF power processing unit, and a power storage and supply unit. The power processing and control unit comprises a DC power processing unit and a digital interface and control unit. The DC power processing unit supplies power to the thruster's shield grid and accelerating grid, as well as the contacts and heaters of the hollow cathode neutralizer. The digital interface and control unit performs the measurement and control functions for each part of the electric propulsion system. The hollow cathode neutralizer is primarily responsible for generating electrons and participates in the ignition and neutralization processes of the RF ion thruster.

[0003] During the ignition process of the radio frequency ion thruster, the emitter inside the hollow cathode neutralizer is first preheated by its heater to reach the electron emission temperature. Then, a high voltage is applied to the contacts of the hollow cathode neutralizer, causing the working gas to discharge and break down. The neutralizer then emits an electron beam. At this time, a positive high voltage is applied to the thruster's grid, introducing external electrons into the discharge chamber. Under the influence of the electromagnetic field, the electrons collide with neutral atoms inside the discharge chamber, ionizing them and generating plasma, thus completing the thruster ignition. After successful thruster ignition, the hollow cathode neutralizer continues to generate electrons to neutralize the plasma ejected from the thruster, maintaining the electrical neutrality of the entire radio frequency ion electric propulsion system and ensuring its stable operation.

[0004] During the ignition process of a radio frequency ion thruster, the amount of electrons generated at the moment of working gas discharge breakdown at the contact electrode of the hollow cathode neutralizer, i.e., the magnitude of the instantaneous ignition current at the contact electrode, directly affects the reliability of the thruster's successful ignition. A larger instantaneous ignition current at the contact electrode leads to higher reliability of the thruster's ignition. Simultaneously, after high-voltage ignition, the contact electrode of the hollow cathode neutralizer needs to quickly switch to a constant current stable output state to avoid instability in the emitted electron quantity, which could lead to thruster instability and frequent sparking. With the increase in the number of ignitions and usage time, the no-load equivalent impedance and constant current equivalent impedance of the contact electrode of the hollow cathode neutralizer will change. Therefore, it is necessary to improve the stability of the high-voltage output of the contact electrode power supply throughout the thruster's entire life cycle to ensure the reliability of the thruster's ignition; and to adjust the constant current output value of the contact electrode power supply to match the changes in the constant current equivalent impedance of the contact electrode, maintaining the operational stability throughout the thruster's entire life cycle.

[0005] Currently, most hollow cathode neutralizer power supplies adopt an independent power supply architecture, consisting of three parts: a heater power supply, a contact electrode high-voltage power supply, and a contact electrode constant current power supply. Some hollow cathode neutralizer power supplies reuse the heater power supply and the contact electrode constant current power supply, or reuse the inverter circuit sections of the contact electrode high-voltage power supply and the contact electrode constant current power supply. These designs mainly have the following two problems:

[0006] In a radio frequency ion electric propulsion hollow cathode neutralizer, the output current and voltage ranges of the heater power supply and the contact electrode constant current power supply differ significantly. When using a multiplexed design for the heater power supply and the contact electrode constant current power supply, the combined power supply will need to meet a wider output range requirement, resulting in higher output power and the need for additional multiplexing control circuitry, potentially leading to higher component costs compared to an independent power supply architecture. Furthermore, the combined power supply will struggle to maintain high efficiency across a wider output range.

[0007] For both independent power supply architectures and architectures that reuse the inverter circuits of the contact electrode high-voltage power supply and the contact electrode constant current power supply, a voltage divider resistor is typically installed before the contact electrode high-voltage branch and the contact electrode constant current branch are combined. The resistance of the voltage divider resistor is generally more than a thousand times the equivalent impedance of the contact electrode constant current branch. Its function is to withstand high voltage after successful contact electrode ignition, thereby reducing the output power of the high-voltage branch. However, on the one hand, the voltage divider resistor will suppress the discharge current of the contact electrode at the moment of ignition; on the other hand, as the number of ignitions and the usage time increase, the contact electrode open-circuit equivalent impedance of the hollow cathode neutralizer gradually decreases. The voltage divider resistor will cause the contact electrode open-circuit voltage to decrease as its open-circuit equivalent impedance decreases, thus affecting the ignition reliability of the thruster. Therefore, in summary, in the current power supply scheme of the hollow cathode neutralizer of the radio frequency ion electric propulsion system, when the heater power supply and the contact electrode constant current power supply are combined, the efficiency of the combined power supply is not high enough over a wider output range; when a voltage divider resistor is set in the high voltage branch of the contact electrode, the voltage divider resistor will cause the contact electrode open-circuit voltage to decrease as its open-circuit equivalent impedance decreases, thereby affecting the ignition reliability of the thruster. Summary of the Invention

[0008] This invention provides a highly reliable power supply circuit and its operating method for a hollow cathode neutralizer. The purpose is to solve the problems in the current power supply schemes for hollow cathode neutralizers in radio frequency ion electric propulsion systems. When the heater power supply and the contact electrode constant current power supply are multiplexed, the combined power supply is not efficient enough over a wider output range. Furthermore, when a voltage divider resistor is set in the high-voltage branch of the contact electrode, the voltage divider resistor causes the open-circuit voltage of the contact electrode to decrease as its open-circuit equivalent impedance decreases, thereby affecting the ignition reliability of the thruster.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] This invention discloses a power supply circuit for a highly reliable hollow cathode neutralizer. The power supply circuit includes an input filter capacitor Cin, a contact electrode power supply circuit, and a heater power supply circuit, wherein:

[0011] The input filter capacitor Cin is located at the input terminal of the power supply circuit. The input filter capacitor Cin is used to provide a DC voltage source for the contact electrode power supply circuit and the heater power supply circuit.

[0012] The contact electrode power supply circuit includes: a contact electrode power supply primary current sampling circuit, a contact electrode power supply flyback power conversion circuit, a contact electrode power supply output voltage sampling circuit, a contact electrode power supply output current sampling circuit, a contact electrode power supply output voltage PID negative feedback control circuit, a contact electrode power supply output current PID negative feedback control circuit, a feedback signal comparison circuit, a contact electrode power supply PWM pulse width modulation circuit, and a contact electrode power supply isolation drive circuit. The contact electrode power supply circuit is used to perform the first circuit processing on the DC voltage after filtering by the input filter capacitor Cin, so as to form the DC voltage of the neutralizer contact electrode load.

[0013] The heater power supply circuit includes a heater power supply primary current sampling circuit, a heater power supply flyback power conversion circuit, a heater power supply output voltage sampling circuit, a heater power supply output current sampling circuit, a heater power supply output current PID negative feedback control circuit, a heater power supply PWM pulse width modulation circuit, and a heater power supply isolation drive circuit. The heater power supply circuit is used to perform a second circuit processing on the DC voltage filtered by the input filter capacitor Cin in order to form the DC voltage of the neutralizer heater load.

[0014] In some implementations, the primary current sampling circuit of the contact power supply is used to collect the primary current of the contact power supply and send the primary current signal of the contact power supply to the PWM pulse width modulation circuit of the contact power supply; the PWM pulse width modulation circuit of the contact power supply is used to send the pulse width modulation output signal to the isolation drive circuit of the contact power supply.

[0015] Furthermore, the contact electrode power supply isolation drive circuit is used to achieve magnetic isolation through the drive transformer, output a first drive signal, and send the first drive signal to the contact electrode power supply flyback power conversion circuit.

[0016] Furthermore, the contact electrode power supply flyback power conversion circuit is used to receive the first drive signal, realize switch control and duty cycle adjustment, and achieve magnetic isolation between the primary and secondary sides through the power transformer.

[0017] In some implementations, the contact electrode power supply output voltage sampling circuit is used to convert the contact electrode power supply output voltage signal into a sampling signal Vcy1, and send the sampling signal Vcy1 to the contact electrode power supply output voltage PID negative feedback control circuit.

[0018] Furthermore, the contact electrode power supply output current sampling circuit is used to: convert the contact electrode power supply output current signal into a sampling signal Icy1, and send the sampling signal Icy1 to the contact electrode power supply output voltage PID negative feedback control circuit.

[0019] Furthermore, the PID negative feedback control circuit for the contact electrode power supply output voltage is used to: compare the sampled signal Vcy1 with the reference signal Vset1, perform negative feedback PID loop calculation, form the contact electrode power supply output voltage feedback signal, and output it to the feedback signal comparison circuit;

[0020] The contact electrode power supply output current PID negative feedback control circuit is used to: compare the sampled signal Icy1 with the reference signal Iset1, perform negative feedback PID loop operation, form the contact electrode power supply output current feedback signal, and output it to the feedback signal comparison circuit.

[0021] In some implementations, the feedback signal comparison circuit is used to compare the output signals of the contact power supply output voltage PID negative feedback control circuit and the contact power supply output current PID negative feedback control circuit, take the lower voltage value as the output to form a feedback loop control signal, and send the feedback loop control signal to the contact power supply PWM pulse width modulation circuit.

[0022] In some implementations, the contact electrode power supply PWM pulse width modulation circuit is used to receive the output signals of the contact electrode power supply primary side current sampling circuit and feedback signal comparison circuit to realize power supply soft start, primary side overcurrent protection and PWM pulse width adjustment.

[0023] The present invention also provides a method for operating a power supply circuit for a highly reliable hollow cathode neutralizer, comprising the following steps:

[0024] S1. Set the power supply output current reference signal, power supply output voltage reference signal, and heater power supply output current reference signal respectively;

[0025] S2. Turn on the heating power;

[0026] S3, the neutralizer is preheated.

[0027] S4. Determine whether the heating process of the neutralizer is complete based on the neutralizer status or the set heating time; if not, return to S3; if complete, proceed to S5.

[0028] S5. Turn on the power supply to the contact electrode;

[0029] S6. Determine whether the thruster ignition is successful based on the working status of the thruster and neutralizer; if ignition is unsuccessful, turn off the contact electrode power supply and return to S3; if ignition is successful, proceed to S7.

[0030] S7. Turn off the heater power;

[0031] S8. Adjust the power supply output current reference signal of the contact electrode according to the operating status of the thruster;

[0032] S9. The thruster has finished working and the contact electrode power supply is turned off.

[0033] Compared with the prior art, the power supply circuit and its working method for a highly reliable hollow cathode neutralizer of the present invention have the following advantages:

[0034] This invention discloses a power supply circuit for a highly reliable hollow cathode neutralizer. The power supply circuit includes an input filter capacitor Cin, a contact electrode power supply circuit, and a heater power supply circuit. The input filter capacitor Cin is located at the input terminal of the power supply circuit and provides a DC voltage source to the contact electrode power supply circuit and the heater power supply circuit. The contact electrode power supply circuit includes: a contact electrode power supply primary-side current sampling circuit, a contact electrode power supply flyback power conversion circuit, a contact electrode power supply output voltage sampling circuit, a contact electrode power supply output current sampling circuit, a contact electrode power supply output voltage PID negative feedback control circuit, a contact electrode power supply output current PID negative feedback control circuit, a feedback signal comparison circuit, and a contact electrode power supply PWM pulse width controller. The invention comprises a modulation circuit and a contact electrode power supply isolation drive circuit. The contact electrode power supply circuit performs a first circuit processing on the DC voltage filtered by the input filter capacitor Cin to form the DC voltage of the neutralizer contact electrode load. The heater power supply circuit includes a heater power supply primary current sampling circuit, a heater power supply flyback power conversion circuit, a heater power supply output voltage sampling circuit, a heater power supply output current sampling circuit, a heater power supply output current PID negative feedback control circuit, a heater power supply PWM pulse width modulation circuit, and a heater power supply isolation drive circuit. The heater power supply circuit performs a second circuit processing on the DC voltage filtered by the input filter capacitor Cin to form the DC voltage of the neutralizer heater load. Based on the above, this invention can be used for radio frequency ion electric propulsion. This high-reliability hollow cathode neutralizer power supply circuit consists of independent heater power supplies and contact electrode power supplies. It achieves two power supply modes—no-load high-voltage output and loaded constant-current output—through a single contact electrode power supply. The output range of each power supply fully meets its load power supply requirements, and no additional multiplexing control circuit is needed. The number of components used is small, the power supply efficiency is high, and the workflow is clear and reliable. Furthermore, the contact electrode power supply of this invention possesses both no-load high-voltage output and on-load constant-current output characteristics. It can adaptively adjust the output mode according to the impedance state of the contact electrode of the hollow cathode neutralizer, providing sufficient electron quantity at the moment of contact electrode ignition. Moreover, its no-load output voltage is not affected by the no-load equivalent impedance of the contact electrode, achieving stable no-load high-voltage output throughout the entire life cycle of the thruster, thereby ensuring the reliability of successful ignition throughout the entire life cycle of the thruster. After successful ignition, the contact electrode power supply can adaptively change the contact electrode impedance state, rapidly (on the millisecond level) automatically switching from no-load high-voltage output to constant-current output mode, thereby ensuring the operational stability of the thruster. During thruster operation, the constant-current output values ​​of the contact electrode power supply and the heating power supply can be adjusted on-orbit to match the changes in the constant-current equivalent impedance of the contact electrode, maintaining operational stability throughout the entire life cycle of the thruster. Attached Figure Description

[0035] The accompanying drawings are provided to further understand the invention and constitute a part of this invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0036] Figure 1 This is a schematic diagram of the power circuit topology in the power circuit and its working method of a highly reliable hollow cathode neutralizer of the present invention.

[0037] Figure 2 This is a schematic diagram illustrating the operation of the power supply circuit and its working method for a highly reliable hollow cathode neutralizer according to the present invention. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0039] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0040] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0041] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0042] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0043] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0044] How to improve the ignition reliability and operational stability throughout the entire life cycle of the hollow cathode neutralizer in a radio frequency ion electric propulsion system, in response to its power supply requirements.

[0045] like Figure 1 As shown, this invention proposes a power supply circuit for a highly reliable hollow cathode neutralizer. The power supply circuit includes an input filter capacitor Cin, a contact electrode power supply circuit, and a heater power supply circuit, wherein:

[0046] The input filter capacitor Cin is located at the input terminal of the power supply circuit. The input filter capacitor Cin is used to provide a DC voltage source for the contact electrode power supply circuit and the heater power supply circuit.

[0047] The contact electrode power supply circuit includes: a contact electrode power supply primary current sampling circuit, a contact electrode power supply flyback power conversion circuit, a contact electrode power supply output voltage sampling circuit, a contact electrode power supply output current sampling circuit, a contact electrode power supply output voltage PID negative feedback control circuit, a contact electrode power supply output current PID negative feedback control circuit, a feedback signal comparison circuit, a contact electrode power supply PWM pulse width modulation circuit, and a contact electrode power supply isolation drive circuit. The contact electrode power supply circuit is used to perform the first circuit processing on the DC voltage after filtering by the input filter capacitor Cin, so as to form the DC voltage of the neutralizer contact electrode load.

[0048] The heater power supply circuit includes a heater power supply primary current sampling circuit, a heater power supply flyback power conversion circuit, a heater power supply output voltage sampling circuit, a heater power supply output current sampling circuit, a heater power supply output current PID negative feedback control circuit, a heater power supply PWM pulse width modulation circuit, and a heater power supply isolation drive circuit. The heater power supply circuit is used to perform a second circuit processing on the DC voltage filtered by the input filter capacitor Cin in order to form the DC voltage of the neutralizer heater load.

[0049] In this invention, a power supply circuit for a highly reliable hollow cathode neutralizer allows the contact electrode power supply to adaptively adjust its output mode based on the impedance state of the contact electrodes. During thruster ignition, the contact electrode power supply ensures successful ignition. Simultaneously, the output voltage of this invention is unaffected by the contact electrode's no-load equivalent impedance, enabling stable no-load high-voltage output throughout the thruster's entire lifespan, thereby improving the thruster's ignition reliability. After successful ignition, the power supply adaptively switches from no-load high-voltage output to constant current output mode, adapting to changes in contact electrode impedance. This ensures thruster stability during operation and avoids frequent sparking caused by contact electrode impedance variations. The power supply circuit of this invention matches changes in the contact electrode's constant current equivalent impedance, maintaining operational stability throughout the thruster's entire lifespan.

[0050] The following detailed description of the power supply circuit and operating method of a highly reliable hollow cathode neutralizer according to the present invention will be provided through specific embodiments.

[0051] like Figure 1 As shown, the power supply circuit of the present invention consists of an input filter capacitor Cin, a contact electrode power supply circuit, and a heater power supply circuit.

[0052] Input filter capacitor Cin: One end of the input filter capacitor Cin is connected to the positive power supply line Vin+, and the other end is connected to the return power supply line VinGnd.

[0053] By utilizing the energy storage and release characteristics of the input filter capacitor Cin, the peak-to-peak value of the AC ripple of the power supply bus is reduced, enabling efficient and smooth DC output. At the same time, high-frequency noise in the power supply is filtered out, ensuring the stability and reliability of the circuit.

[0054] In the power supply circuit of this invention, the contact electrode power supply circuit comprises: a contact electrode power supply primary current sampling circuit, a contact electrode power supply flyback power conversion circuit, a contact electrode power supply output voltage sampling circuit, a contact electrode power supply output current sampling circuit, a contact electrode power supply output voltage PID negative feedback control circuit, a contact electrode power supply output current PID negative feedback control circuit, a feedback signal comparison circuit, a contact electrode power supply PWM pulse width modulation circuit, and a contact electrode power supply isolation drive circuit.

[0055] In the power supply circuit of this invention, the primary current sampling circuit of the contact power supply consists of a current transformer T2, a magnetic reset resistor R1, a filter capacitor C3, a signal output diode V3, and a current-to-voltage signal conversion resistor R2. Pin 1 of the current transformer T2 is connected to the positive power supply line Vin+, pin 2 is connected to pin 1 of the power transformer T1 in the contact power supply flyback power conversion circuit, pin 3 is connected to the anode of the signal output diode V3, and pin 4 is connected to the neutralizer power supply internal control ground CGnd. Pins 1 and 3 of the current transformer T2 are of the same name, and pins 2 and 4 are of the same name. The magnetic reset resistor R1 and the filter capacitor C3 are connected in parallel, with one end connected to pin 3 of the current transformer T2 and the other end connected to pin 4 of the current transformer T2. The anode of the signal output diode V3 is connected to pin 3 of the current transformer T2, and the cathode is connected to the primary current sampling signal IS1 of the contact power supply. One end of the current-to-voltage signal conversion resistor R2 is connected to the primary current sampling signal IS1 of the contact power supply, and the other end is connected to the internal control ground CGnd of the neutralizer power supply.

[0056] In the power supply circuit of this invention, the primary current sampling circuit of the contact electrode power supply collects the primary current of the contact electrode power supply through the current transformer T2, and sends the primary current sampling signal IS1 of the contact electrode power supply to the PWM pulse width modulation circuit of the contact electrode power supply, thereby realizing the overcurrent protection of the primary side of the contact electrode power supply. The function of the magnetic reset resistor R1 is to perform magnetic reset of the current transformer T2 when the primary current of the contact electrode power supply returns to zero, so as to avoid magnetic saturation of the current transformer T2. The current-to-voltage signal conversion resistor R2 converts the current signal output by the signal output diode V3 into a voltage signal.

[0057] In the power supply circuit of this invention, the contact-electrode flyback power conversion circuit consists of a resistor R3, a capacitor C2, a diode V2, a power transformer T1, an N-MOS transistor Q1, an output rectifier diode V1, and an output filter capacitor C1. The resistor R3 and capacitor C2 are connected in parallel, with one end connected to pin 1 of the power transformer T1 and the other end connected to the cathode of the diode V2. The anode of the diode V2 is connected to pin 2 of the power transformer T1. The drain of the N-MOS transistor Q1 is connected to pin 2 of the power transformer T1, the source is connected to the power supply return line VinGnd, and the gate is connected to the first drive signal V. Q1gs Pin 3 of the power transformer T1 is connected to the anode of the output rectifier diode V1, and pin 4 is connected to one end of the output filter capacitor C1. Pins 1 and 4 are of the same name, and pins 2 and 3 are of the same name. The cathode of the output rectifier diode V1 is connected to the other end of the output filter capacitor C1, which is the positive terminal Vout1+ of the contact power supply output.

[0058] In the power supply circuit of this invention, the NMOS transistor Q1 in the contact power supply flyback power conversion circuit receives the first drive signal V output by the contact power supply isolation drive circuit. Q1gs This system enables switching control and duty cycle adjustment, and achieves magnetic isolation between the primary and secondary sides through power transformer T1. Its basic working principle is as follows: When the N-MOSFET Q1 is turned on, power transformer T1 stores energy, output rectifier diode V1 is cut off, and output filter capacitor C1 supplies power to the downstream load; when the N-MOSFET Q1 is turned off, power transformer T1 supplies power to the secondary side, output rectifier diode V1 conducts, charging output filter capacitor C1 and simultaneously supplying power to the downstream load. Resistor R3, capacitor C2, and diode V2 constitute an RCD voltage spike absorption circuit. The function of the RCD voltage spike absorption circuit is to absorb the drain-source voltage spike when the N-MOSFET Q1 is turned off, preventing excessive stress on the power MOSFET's turn-off voltage.

[0059] In the power supply circuit of this invention, one end of the contact electrode power supply output voltage sampling circuit is connected to the positive terminal Vout1+ of the contact electrode power supply output, and the other end is connected to the common ground VoutGnd of the hollow cathode neutralizer power supply output. The contact electrode power supply output voltage sampling circuit converts the contact electrode power supply output voltage signal into a contact electrode power supply output voltage sampling signal Vcy1, while simultaneously achieving high-impedance isolation between the common ground VoutGnd of the hollow cathode neutralizer power supply output and the internal control ground CGnd of the neutralizer power supply, thus preventing ground disturbances on the neutralizer load side from affecting the steady-state operation of the power supply during the operation of the contact electrode power supply.

[0060] One end of the contact electrode power supply output current sampling circuit is connected to pin 4 of the power transformer T1, and the other end is connected to the common ground line VoutGnd of the hollow cathode neutralizer power supply output. The contact electrode power supply output current sampling circuit converts the contact electrode power supply output current signal into the contact electrode power supply output current sampling signal Icy1, and at the same time achieves high-impedance isolation between the common ground line VoutGnd of the hollow cathode neutralizer power supply output and the neutralizer power supply internal control ground CGnd, so as to avoid the neutralizer load side ground line disturbance affecting the steady-state operation of the power supply during the operation of the contact electrode power supply.

[0061] In the power supply circuit of this invention, the PID negative feedback control circuit for the contact power supply output voltage consists of an operational amplifier N2, resistors R7-R9, and capacitors C7-C9. Resistor R8 is connected in series with capacitor C7, and then in parallel with resistor R7, forming a RC network. One end of this network is connected to the contact power supply output voltage sampling signal Vcy1, and the other end is connected to the inverting input of operational amplifier N2. Resistor R9 is connected in series with capacitor C9, and then in parallel with capacitor C8, forming a RC network. One end of this network is connected to the inverting input of operational amplifier N2, and the other end is connected to the output terminal of operational amplifier N2. The output terminal of operational amplifier N2 is also connected to the cathode of diode V5 in the feedback signal comparator circuit. The non-inverting input of operational amplifier N2 is connected to the contact power supply output voltage reference signal Vset1.

[0062] The contact power supply output voltage PID negative feedback control circuit receives the contact power supply output voltage sampling signal Vcy1 from the contact power supply output voltage sampling circuit, compares it with the contact power supply output voltage reference signal Vset1 at the non-inverting input of the operational amplifier, performs negative feedback PID loop calculation, and finally forms the contact power supply output voltage feedback signal.

[0063] The PID negative feedback control circuit for the contact power supply output current consists of operational amplifier N1, resistors R4-R6, and capacitors C4-C6. Resistor R5 is connected in series with capacitor C4, then in parallel with resistor R4, forming an RC network. One end of this network is connected to the contact power supply output current sampling signal Icy1, and the other end is connected to the inverting input of operational amplifier N1. Resistor R6 is connected in series with capacitor C6, then in parallel with capacitor C5, forming an RC network. One end of this network is connected to the inverting input of operational amplifier N1, and the other end is connected to the output terminal of operational amplifier N1. The output terminal of operational amplifier N1 is also connected to the cathode of diode V4 in the feedback signal comparator circuit. The non-inverting input of operational amplifier N1 is connected to the contact power supply output current reference signal Iset1.

[0064] The contact power supply output current PID negative feedback control circuit receives the contact power supply output current sampling signal Icy1 from the contact power supply output current sampling circuit, compares it with the contact power supply output current reference signal Iset1 at the non-inverting input of the operational amplifier, performs negative feedback PID loop calculation, and finally forms the contact power supply output current feedback signal.

[0065] In the power supply circuit of this invention, the feedback signal comparison circuit consists of diodes V4 to V5. The cathode of diode V4 is connected to the output terminal of operational amplifier N1, and the anode is connected to the feedback loop control signal. The cathode of diode V5 is connected to the output terminal of operational amplifier N2, and the anode is connected to the feedback loop control signal.

[0066] The feedback signal comparison circuit receives the output voltage feedback signal from the contact electrode power supply output voltage PID negative feedback control circuit and the output current feedback signal from the contact electrode power supply output current PID negative feedback control circuit, compares the two, takes the lower voltage value as the output, and sends the final feedback loop control signal to the contact electrode power supply PWM pulse width modulation circuit.

[0067] In the power supply circuit of the present invention, the contact electrode power supply PWM pulse width modulation circuit receives the contact electrode power supply primary side current sampling signal IS1 and the feedback loop control signal. Through the peripheral circuit of the PWM pulse width controller, it realizes the functions of power supply soft start-up, primary side overcurrent protection, current slope compensation, PWM pulse width adjustment, etc., and sends the pulse width modulation output signal PWM1 to the contact electrode power supply isolation drive circuit.

[0068] The contact electrode power supply isolation drive circuit receives the pulse width modulation output signal PWM1 from the contact electrode power supply PWM circuit, achieves magnetic isolation through the drive transformer, and outputs the first drive signal V. Q1gs The signal is sent to the gate of N MOS transistor Q1 in the contact electrode power supply flyback power conversion circuit.

[0069] In the power supply circuit of this invention, the contact electrode power supply body adopts a flyback power converter, which simultaneously samples the primary current signal, output voltage signal and output current signal, and transmits the sampled signals to the relevant functional circuits, thereby realizing functions such as primary overcurrent protection, output voltage PID negative feedback control and output current PID negative feedback control.

[0070] The overall working mechanism of the contact electrode power supply is as follows: During the thruster ignition process, the initial state of the contact electrode of the hollow cathode neutralizer is a high-resistance state. At this time, the output current of the contact electrode power supply is approximately zero, and the voltage of the contact electrode power supply output current sampling signal Icy1 is low. The output voltage of the contact electrode power supply output current PID negative feedback control circuit is higher than the output voltage of the contact electrode power supply output voltage PID negative feedback control circuit. The contact electrode power supply operates in the voltage loop, achieving stable constant voltage output under no-load conditions. When high voltage is applied to the contact electrode of the hollow cathode neutralizer, the working gas is discharged and broken down. The output current of the contact electrode power supply gradually increases to the set contact electrode power supply output current reference signal Iset1. At this point, the output voltage of the contact electrode power supply output current PID negative feedback control circuit is lower than the output voltage of the contact electrode power supply output voltage PID negative feedback control circuit. The contact electrode power supply operates in the current loop, achieving stable constant current output under load. The contact electrode power supply can adaptively adjust to both no-load high-voltage output and on-load constant-current output based on the contact electrode load impedance state of the hollow cathode neutralizer. It provides sufficient electrons at the moment of contact electrode ignition, and its no-load output voltage is not affected by the no-load equivalent impedance of the contact electrode. It can achieve stable no-load high-voltage output throughout the entire life cycle of the thruster, thereby ensuring the reliability of successful ignition throughout the entire life cycle of the thruster. After successful ignition, the contact electrode power supply can adaptively switch from no-load high-voltage output to constant-current output mode rapidly (on the order of milliseconds) to adapt to changes in the contact electrode impedance state, thereby ensuring the operational stability of the thruster. During the operation of the thruster, the constant-current output value of the contact electrode power supply can be adjusted on-orbit to match the changes in the constant-current equivalent impedance of the contact electrode, thereby maintaining the operational stability of the thruster throughout its entire life cycle.

[0071] As some preferred embodiments, optionally;

[0072] The present invention can add an inverted follower circuit after the sampling circuit of the contact electrode power supply output voltage. The output signal of this circuit is the telemetry signal of the contact electrode power supply output voltage, thereby realizing the telemetry function of the contact electrode power supply output voltage.

[0073] The present invention can add an inverted follower circuit after the sampling circuit of the contact electrode power supply output current. The output signal of this circuit is the telemetry signal of the contact electrode power supply output current, thereby realizing the telemetry function of the contact electrode power supply output current.

[0074] This invention can divide the Vref level output by the PWM pulse width controller in the PWM pulse width modulation circuit of the contact electrode power supply with a resistor to form the contact electrode power supply output voltage reference signal Vset1;

[0075] This invention can divide the Vref level output by the PWM pulse width controller in the PWM pulse width modulation circuit of the contact electrode power supply with a resistor to form the contact electrode power supply output current reference signal Iset1;

[0076] This invention can replace the reference signal Vset1 of the contact electrode power supply output voltage in the PID negative feedback control circuit with an externally injected level, thereby realizing the remote control function of the contact electrode power supply output voltage.

[0077] This invention can replace the reference signal Iset1 of the contact electrode power supply output current in the PID negative feedback control circuit with an externally injected level, thereby realizing the remote control function of the contact electrode power supply output current.

[0078] In the power supply circuit of this invention, the heater power supply circuit consists of a heater power supply primary current sampling circuit, a heater power supply flyback power conversion circuit, a heater power supply output voltage sampling circuit, a heater power supply output current sampling circuit, a heater power supply output current PID negative feedback control circuit, a heater power supply PWM pulse width modulation circuit, and a heater power supply isolation drive circuit.

[0079] The heater power supply primary-side current sampling circuit consists of a current transformer T4, a magnetic reset resistor R10, a filter capacitor C10, a signal output diode V8, and a current-to-voltage signal conversion resistor R11. Pin 1 of the current transformer T4 is connected to the positive power supply line Vin+. Pin 2 of the current transformer T4 is connected to pin 1 of the power transformer T3 in the heater power supply flyback power conversion circuit. Pin 3 of the current transformer T4 is connected to the anode of the signal output diode V8. Pin 4 of the current transformer T4 is connected to the neutralizer power supply internal control ground CGnd. Pins 1 and 3 of the current transformer T4 are of the same name, as are pins 2 and 4. The magnetic reset resistor R10 and the filter capacitor C10 are connected in parallel, with one end connected to pin 3 of the current transformer T4 and the other end connected to pin 4 of the current transformer T4. The anode of the signal output diode V8 is connected to pin 3 of the current transformer T4, and the cathode is connected to the heater power supply primary-side current sampling signal IS2. One end of the current-to-voltage signal conversion resistor R11 is connected to the primary current sampling signal IS2 of the heater power supply, and the other end is connected to the internal control ground CGnd of the neutralizer power supply.

[0080] The heater power supply primary-side current sampling circuit collects the heater power supply primary-side current through current transformer T4 and sends the primary-side current sampling signal IS2 to the heater power supply PWM pulse width modulation circuit, thereby realizing primary-side overcurrent protection of the heater power supply. The magnetic reset resistor R11 performs a magnetic reset of current transformer T4 when the heater power supply primary-side current returns to zero, preventing magnetic saturation of current transformer T4. The current-to-voltage signal conversion resistor R11 converts the current signal output by signal output diode V8 into a voltage signal.

[0081] In the power supply circuit of this invention, the heater power supply flyback power conversion circuit consists of a resistor R12, a capacitor C11, a diode V7, a power transformer T3, an N MOS transistor Q2, an output rectifier diode V6, and an output filter capacitor C12. The resistor R12 and capacitor C11 are connected in parallel, with one end connected to pin 1 of the power transformer T3 and the other end connected to the cathode of the diode V7. The anode of the diode V7 is connected to pin 2 of the power transformer T3. The drain of the N MOS transistor Q2 is connected to pin 2 of the power transformer T3, the source is connected to the power supply return line VinGnd, and the gate is connected to the second drive signal V. Q2gs Pin 3 of power transformer T3 is connected to the anode of output rectifier diode V6, and pin 4 is connected to one end of output filter capacitor C12. Pins 1 and 4 are equivalent terminals, and pins 2 and 3 are equivalent terminals. The cathode of output rectifier diode V6 is connected to the other end of output filter capacitor C12, which is the positive terminal Vout2+ of the heater power supply output.

[0082] In the heater power supply flyback power converter circuit, N MOS transistor Q2 receives the second drive signal V output from the heater power supply isolation drive circuit. Q2gs This system enables switching control and duty cycle adjustment, and achieves primary-secondary magnetic isolation through power transformer T3. Its basic working principle is as follows: When NMOS transistor Q2 is turned on, power transformer T3 stores energy, output rectifier diode V6 is cut off, and output filter capacitor C12 supplies power to the downstream load; when NMOS transistor Q2 is turned off, power transformer T3 supplies power to the secondary side, output rectifier diode V6 conducts, charging output filter capacitor C12 and simultaneously supplying power to the downstream load. Resistor R12, capacitor C11, and diode V7 constitute an RCD voltage spike absorption circuit. The function of the RCD voltage spike absorption circuit is to absorb the drain-source voltage spike when NMOS transistor Q2 is turned off, preventing excessive stress on the power MOS transistor's turn-off voltage.

[0083] One end of the heater power supply output voltage sampling circuit is connected to the positive terminal Vout2+ of the heater power supply output, and the other end is connected to the common ground VoutGnd of the hollow cathode neutralizer power supply output. This circuit converts the heater power supply output voltage signal into a sampling signal Vcy2, while simultaneously achieving high-impedance isolation between the common ground VoutGnd of the hollow cathode neutralizer power supply output and the internal control ground CGnd of the neutralizer power supply. This prevents grounding disturbances on the neutralizer load side from affecting the steady-state operation of the power supply during heater power supply operation.

[0084] One end of the heater power supply output current sampling circuit is connected to pin 4 of the power transformer T3, and the other end is connected to the common ground line VoutGnd of the hollow cathode neutralizer power supply output. The heater power supply output current sampling circuit converts the heater power supply output current signal into the heater power supply output current sampling signal Icy2, and at the same time achieves high-impedance isolation between the common ground line VoutGnd of the hollow cathode neutralizer power supply output and the neutralizer power supply internal control ground CGnd, so as to avoid the neutralizer load side ground line disturbance affecting the steady-state operation of the power supply during the operation of the heater power supply.

[0085] In the power supply circuit of this invention, the PID negative feedback control circuit for the heater power supply output current consists of operational amplifier N3, resistors R13-R15, and capacitors C13-C15. Resistor R14 is connected in series with capacitor C13, and then in parallel with resistor R13, forming an RC network. One end of this network is connected to the heater power supply output current sampling signal Icy2, and the other end is connected to the inverting input of operational amplifier N3. Resistor R15 is connected in series with capacitor C15, and then in parallel with capacitor C14, forming an RC network. One end of this network is connected to the inverting input of operational amplifier N3, and the other end is connected to the output terminal of operational amplifier N3. The output terminal of operational amplifier N3 is also connected to the heater power supply PWM pulse width modulation circuit. The non-inverting input of operational amplifier N3 is connected to the heater power supply output current reference signal Iset2.

[0086] The heater power supply output current PID negative feedback control circuit receives the heater power supply output current sampling signal Icy2 from the heater power supply output current sampling circuit, compares it with the heater power supply output current reference signal Iset2 at the non-inverting input of the operational amplifier, performs negative feedback PID loop operation, and finally forms the heater power supply output current feedback signal.

[0087] The heater power supply PWM pulse width modulation circuit receives the heater power supply primary side current sampling signal IS2 and the heater power supply output current feedback signal. Through the PWM pulse width controller and its peripheral circuit, it realizes functions such as power supply soft start-up, primary side overcurrent protection, current slope compensation, and PWM pulse width adjustment, and sends the pulse width modulation output signal PWM2 to the heater power supply isolation drive circuit.

[0088] The heater power supply isolation drive circuit receives the pulse width modulation output signal PWM2 from the heater power supply PWM circuit, achieves magnetic isolation through the drive transformer, and outputs the second drive signal V. Q2gs It is sent to the gate of N MOS transistor Q2 in the heater power supply flyback power conversion circuit.

[0089] The heater power supply adopts a flyback power converter, which samples the primary current signal, output voltage signal and output current signal, and transmits the sampled signals to the relevant functional circuits, thereby realizing functions such as primary overcurrent protection and output current PID negative feedback control. It can adjust the constant current output value of the heater power supply on the orbit during the operation of the thruster, thereby matching the working requirements of the neutralizer and maintaining the working stability of the thruster throughout its entire life cycle.

[0090] As some preferred embodiments, optionally;

[0091] The present invention can add an inverse follower circuit after the heater power supply output voltage sampling circuit. The output signal of this circuit is the telemetry signal of the heater power supply output voltage, thereby realizing the telemetry function of the heater power supply output voltage.

[0092] The present invention can add an inverse follower circuit after the heater power supply output current sampling circuit. The output signal of this circuit is the telemetry signal of the heater power supply output current, thereby realizing the remote measurement function of the heater power supply output current.

[0093] This invention can divide the Vref level output by the PWM pulse width controller in the heater power supply PWM pulse width modulation circuit with resistors to form the heater power supply output current reference signal Iset2;

[0094] This invention can replace the heater power output current reference signal Iset2 in the heater power output current PID negative feedback control circuit with an externally injected level, thereby realizing the remote control function of heater power output current.

[0095] like Figure 2 As shown, the present invention also provides a method for operating the power supply circuit of a highly reliable hollow cathode neutralizer, the specific steps of which are as follows:

[0096] Step 1: Set the contact electrode power supply output current reference signal Iset1, the contact electrode power supply output voltage reference signal Vset1, and the heater power supply output current reference signal Iset2 respectively;

[0097] Step 2: Turn on the heating power;

[0098] Step 3: Preheat the neutralizer;

[0099] Step 4: Determine whether the heating process of the neutralizer is complete based on the neutralizer status or the set heating time. If it is complete, proceed to Step 5; otherwise, return to Step 3.

[0100] Step 5: Turn on the power to the contact electrode;

[0101] Step Six: Determine whether the thruster ignition is successful based on the working status of the thruster and neutralizer. If ignition is successful, proceed to Step Seven. If ignition is unsuccessful, turn off the contact electrode power supply and return to Step Three.

[0102] Step 7: Turn off the heater power;

[0103] Step 8: Adjust the contact electrode power supply output current reference signal Iset1 according to the thruster operating status;

[0104] Step 9: After the thruster finishes working, turn off the power supply to the contact electrode.

[0105] In summary, this invention improves power conversion efficiency and enhances anti-interference capability and stability by employing a flyback power converter's contact electrode power supply and heater power supply, and by sampling and feedback control of the primary-side current signal, output voltage signal, and output current signal. Through a PID negative feedback control circuit, the power supply can precisely adjust the output voltage and output current, thereby meeting the high power supply requirements of the radio frequency ion electric propulsion hollow cathode neutralizer. After successful ignition, the contact electrode power supply of this invention can adaptively switch from no-load high-voltage output to constant current output mode rapidly (on the millisecond level) after changes in contact electrode impedance, thus ensuring the thruster's operational stability. Furthermore, it can adjust the constant current output values ​​of the contact electrode power supply and heater power supply on-orbit during thruster operation to match changes in the contact electrode constant current equivalent impedance, maintaining operational stability throughout the thruster's entire lifespan.

[0106] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Those skilled in the art can readily implement the present invention according to the description and above. However, any modifications, alterations, or variations made by those skilled in the art without departing from the scope of the present invention, based on the disclosed technical content, are equivalent embodiments of the present invention. Furthermore, any equivalent changes, alterations, or variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.

Claims

1. A power supply circuit for a highly reliable hollow cathode neutralizer, characterized in that, The power supply circuit includes an input filter capacitor Cin, a contact electrode power supply circuit, and a heater power supply circuit, wherein: The input filter capacitor Cin is located at the input terminal of the power supply circuit. The input filter capacitor Cin is used to provide a DC voltage source for the contact electrode power supply circuit and the heater power supply circuit. The contact electrode power supply circuit includes: a contact electrode power supply primary current sampling circuit, a contact electrode power supply flyback power conversion circuit, a contact electrode power supply output voltage sampling circuit, a contact electrode power supply output current sampling circuit, a contact electrode power supply output voltage PID negative feedback control circuit, a contact electrode power supply output current PID negative feedback control circuit, a feedback signal comparison circuit, a contact electrode power supply PWM pulse width modulation circuit, and a contact electrode power supply isolation drive circuit; the contact electrode power supply circuit is used to perform a first circuit processing on the DC voltage after filtering by the input filter capacitor Cin, so as to form the DC voltage of the neutralizer contact electrode load; The heater power supply circuit includes a heater power supply primary current sampling circuit, a heater power supply flyback power conversion circuit, a heater power supply output voltage sampling circuit, a heater power supply output current sampling circuit, a heater power supply output current PID negative feedback control circuit, a heater power supply PWM pulse width modulation circuit, and a heater power supply isolation drive circuit. The heater power supply circuit is used to perform a second circuit processing on the DC voltage filtered by the input filter capacitor Cin in order to form the DC voltage of the neutralizer heater load. The contact electrode power supply output voltage sampling circuit is used to convert the contact electrode power supply output voltage signal into a sampling signal Vcy1, and send the sampling signal Vcy1 to the contact electrode power supply output voltage PID negative feedback control circuit. The contact electrode power supply output current sampling circuit is used to: convert the contact electrode power supply output current signal into a sampling signal Icy1, and send the sampling signal Icy1 to the contact electrode power supply output voltage PID negative feedback control circuit. The contact electrode power supply output voltage PID negative feedback control circuit is used to: compare the sampled signal Vcy1 with the reference signal Vset1, perform negative feedback PID loop operation, form the contact electrode power supply output voltage feedback signal, and output it to the feedback signal comparison circuit. The contact electrode power supply output current PID negative feedback control circuit is used to: compare the sampled signal Icy1 with the reference signal Iset1, perform negative feedback PID loop operation, form the contact electrode power supply output current feedback signal, and output it to the feedback signal comparison circuit. The feedback signal comparison circuit is used to compare the output signals of the contact electrode power supply output voltage PID negative feedback control circuit and the contact electrode power supply output current PID negative feedback control circuit, take the low voltage value as the output to form a feedback loop control signal, and send the feedback loop control signal to the contact electrode power supply PWM pulse width modulation circuit. The contact electrode power supply PWM pulse width modulation circuit is used to receive the output signals of the contact electrode power supply primary side current sampling circuit and feedback signal comparison circuit, so as to realize power supply soft start, primary side overcurrent protection and PWM pulse width adjustment.

2. The high reliable power supply circuit for a hollow cathode neutralizer according to claim 1, wherein The holding electrode power source primary side current sampling circuit is used for collecting the holding electrode power source primary side current and sending the holding electrode power source primary side current signal to the holding electrode power source PWM pulse width modulation circuit; the holding electrode power source PWM pulse width modulation circuit is used for sending a pulse width modulation output signal to the holding electrode power source isolation driving circuit.

3. The high reliable power supply circuit for a hollow cathode neutralizer according to claim 2, wherein The holding electrode power source isolation driving circuit is used for realizing magnetic isolation through a driving transformer, outputting a first driving signal, and sending the first driving signal to the holding electrode power source flyback power conversion circuit.

4. The high reliable power supply circuit for a hollow cathode neutralizer according to claim 3, wherein The holding electrode power source flyback power conversion circuit is used for receiving the first driving signal, realizing switch control and duty cycle adjustment, and realizing primary and secondary magnetic isolation through a power transformer.

5. The method of claim 1-4, wherein the method further comprises: The method comprises the following steps: S1, setting a holding electrode power source output current reference signal, a holding electrode power source output voltage reference signal and a heater power source output current reference signal respectively; S2, starting a heating power source; S3, preheating a neutralizer, S4, judging whether the heating link of the neutralizer is completed according to the state of the neutralizer or the set heating time; if not, returning to S3; if yes, entering S5; S5, starting the holding electrode power source; S6, judging whether the thruster ignition is successful according to the working state of the thruster and the neutralizer; if not, closing the holding electrode power source and returning to S3; if yes, entering S7; S7, closing the heater power source; S8, adjusting the holding electrode power source output current reference signal according to the running state of the thruster; S9, closing the holding electrode power source when the thruster work is completed.

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