Aircraft ground static variable power supply supporting zero crossing and low crossing and control method and working method thereof

Abstract

The invention discloses an aircraft ground static variable power supply supporting zero crossing and low crossing and a control method and a working method thereof. The aircraft ground static variable power supply comprises a main loop, an energy storage system and an auxiliary power supply part. The main loop consists of an input main switch, an ACDC rectifier, a DCAC inverter and an output contactor which are connected in sequence; the energy storage system is composed of an auxiliary switch, an ACDC charging device and a super capacitor energy storage device which are connected in sequence. Alternating current of a power grid sequentially passes through the auxiliary switch and the ACDC charging device to supply power to the super-capacitor energy storage device, and the super-capacitor energy storage device supports a direct-current bus through a discharging diode; the auxiliary power supply part comprises an isolation transformer and an AC-DC power supply; power grid alternating current is independently input into the alternating-direct current power supply after passing through the isolation transformer, and direct-current bus high-voltage direct current is independently input into the alternating-direct current power supply and outputs low-voltage direct current. The zero crossing time and the low crossing time are increased, the size and the weight of the ground static variable power supply of the airplane are reduced, and the cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft ground services, and in particular to an aircraft ground static variable power supply supporting zero wear-through and low wear-through, and a control method and a working method thereof. Background Art

[0002] Traditional aircraft ground static variable power sources use external batteries or electrolytic capacitors to achieve zero voltage ride-through of the grid. However, the battery discharge rate is small and the electrolytic capacitor has a small capacity, so more batteries or electrolytic capacitors are needed, resulting in a large energy storage system with heavy weight and high cost, making it difficult to popularize in airports.

[0003] The traditional aircraft ground static variable power rectifier module adopts 12-pulse uncontrolled rectification, which has three shortcomings:

[0004] 1. The DC bus voltage of uncontrolled rectification is low, and more energy storage is required.

[0005] 2. Without an external energy storage system, the grid cannot support the output of the load at a lower voltage, that is, the low voltage ride-through function cannot be achieved.

[0006] 3. Under the premise of an external energy storage system, when the grid voltage is low, low-voltage penetration cannot be achieved without controlled rectification and can only be supported by an external energy storage device. The grid cannot provide electrical energy, which reduces the low-voltage penetration time.

[0007] The auxiliary power supply with patent application number "CN202410461504.7" adopts a discrete starting circuit and a common bus circuit, which is large in size and reduces reliability. Summary of the invention

[0008] In view of this, the present invention provides an aircraft ground static variable power supply supporting zero wear and low wear, and a control method and working method thereof, which adopts active rectification and supercapacitor energy storage devices to realize zero wear and low wear functions. By utilizing the characteristics of large capacity and high power density of supercapacitors, less supercapacitors can be used to achieve the same or even longer zero wear time as traditional solutions, and the volume, weight and cost of the equipment are greatly reduced. By utilizing the characteristics of controllable output voltage of active rectification, the function of low voltage ride-through can be realized. When the grid voltage is low, the load power can be fully or partially provided by the grid.

[0009] The present invention discloses an aircraft ground static variable power supply supporting zero wear and low wear, which comprises a main circuit, an energy storage system and an auxiliary power supply part;

[0010] The main circuit is composed of an input main switch, an ACDC rectifier, a DCAC inverter, and an output contactor connected in sequence. The input main switch and the output contactor can be controlled by the control system to realize the disconnection and closing functions. When the low-through or zero-through time exceeds the set value, or the DC bus voltage is lower than the set value, the input main switch and the output contactor are disconnected; the ACDC rectifier adopts an active rectifier topology to convert the AC power of the power grid into high-voltage DC power;

[0011] The energy storage system consists of an auxiliary switch, an ACDC charging device, a supercapacitor energy storage device, and a discharge diode connected in sequence; the AC power of the grid sequentially passes through the auxiliary switch and the ACDC charging device to supply power to the supercapacitor energy storage device, and the supercapacitor energy storage device supports the DC bus through the discharge diode;

[0012] The auxiliary power supply part includes an isolation transformer and an AC / DC power supply; the AC power of the power grid is independently input into the AC / DC power supply after passing through the isolation transformer, and the high-voltage DC power of the DC bus is independently input into the AC / DC power supply to output low-voltage DC power.

[0013] Furthermore, the ACDC rectifier includes an input circuit breaker, an AC inductor, an AC filter capacitor, a semiconductor rectifier, a grid-side DC bus capacitor, and a discharge resistor; the input circuit breaker is connected to the semiconductor rectifier through the AC inductor respectively; an AC filter capacitor is arranged between the input circuit breaker and the AC inductor; the semiconductor rectifier, the discharge resistor and the grid-side DC bus capacitor are connected in parallel.

[0014] Furthermore, the energy storage system includes a charge and discharge control circuit and a supercapacitor energy storage device; the charge and discharge control circuit is composed of a controllable discharge control circuit and a controllable charging circuit; the supercapacitor energy storage device is composed of a plurality of supercapacitor modules connected in series in sequence; the supercapacitor energy storage device is arranged between the controllable discharge control circuit and the controllable charging circuit;

[0015] The controllable discharge control circuit includes a discharge diode, a fuse, a first discharge control switch, a discharge main switch, and a second discharge control switch; the discharge diode, the fuse, the first discharge control switch, and the discharge main switch are connected in series in sequence, and the discharge main switch is connected to the positive electrode of the DC bus capacitor; the positive electrode of the discharge diode is connected to the positive electrode of the energy storage device, and the negative electrode is connected to the fuse; one end of the second discharge control switch is connected to the negative electrode of the energy storage device, and the other end is connected to the negative electrode of the DC bus capacitor;

[0016] The controllable charging device includes a charging protection circuit breaker, a third charging control switch and an ACDC charging device connected in sequence; the charging protection circuit breaker protects the charging circuit and serves as a maintenance switch; the third charging control switch controls the power on of the charging circuit.

[0017] Furthermore, the diode is used for unidirectional discharge; the fuse plays a protective role when the system is short-circuited or severely overloaded; the first discharge control switch and the second discharge control switch are controllable switches to disconnect the energy storage system from the DC bus to achieve safety protection; the main discharge switch uses a circuit breaker as a breakpoint and line protection;

[0018] The energy storage device can be charged by an ACDC charging device, which draws power from the grid, or by a DCDC charging device, which draws power from the DC bus.

[0019] Furthermore, the energy storage system also includes a sampling and controller;

[0020] The sampling and controller is used to collect the total voltage and total current of the energy storage device and the voltage of a single supercapacitor module, and feed it back to the control system of the aircraft ground static variable power supply to control and protect the charging and discharging of the energy storage device.

[0021] Furthermore, the DCAC inverter includes an inverter-side bus capacitor, a bus discharge resistor, a three-phase full-bridge inverter unit and an isolation transformer; the inverter-side bus capacitor, the bus discharge resistor and the three-phase full-bridge inverter unit are connected in parallel; one side of the isolation transformer is connected to the three-phase full-bridge inverter unit; and the other side of the isolation transformer is respectively connected to the filter capacitors.

[0022] The present invention also discloses a control method for an aircraft ground static variable power supply supporting zero wear and low wear, which is applicable to any of the above-mentioned aircraft ground static variable power supplies supporting zero wear and low wear, and comprises:

[0023] The energy storage system supports the DC bus to achieve zero wear;

[0024] When the grid voltage is low, the grid supports the DC bus through active rectification to provide the load with grid power. When the load power is less than or equal to the power that the grid can provide, the load power is completely provided by the grid, and the active rectification output voltage is increased to be greater than the rated voltage of the DC bus. When the load power is greater than the power that the grid can provide, the load power is provided by the grid, and the part of the load power that exceeds the power that the grid can provide is provided by the energy storage system. At this time, the active rectification output voltage is adjusted to be equal to the rated voltage of the DC bus, and decreases as the DC bus voltage drops. When the grid voltage is zero, the load power is completely provided by the energy storage system.

[0025] Furthermore, the active current component is added to the control loop, and the IGBT switching action is driven with different duty cycles through PWM modulation to achieve DC bus voltage stability;

[0026] When the load power is fixed, under different grid voltages, the IGBT duty cycle is adjusted through low voltage ride-through technology to achieve DC bus voltage stability within a specified time;

[0027] When the grid voltage is fixed at low level and the load power is different, the IGBT duty cycle is adjusted through low voltage ride-through technology to achieve stability of the DC bus voltage within a specified time.

[0028] Furthermore, the maximum support time of low voltage ride-through is:

[0029]

[0030] Where, t is the maximum support time of low penetration, k is the overload coefficient, P g is the rated power at the current voltage, t g is the overload time, U max is the maximum DC bus voltage, U min It is the lowest voltage that the DC bus can drop, and P0 is the load power.

[0031] The present invention also discloses a working method of an aircraft ground static variable power supply supporting zero wear and low wear, which is applicable to any of the above-mentioned aircraft ground static variable power supplies supporting zero wear and low wear, and comprises:

[0032] During the first power-on phase of the power grid, the power grid pre-charges the DC bus capacitor through the pre-charging circuit, and then closes the input main switch of the aircraft ground static variable power supply to start the ACDC rectifier. When the DC bus voltage is equal to the set rated voltage, the power grid charges the supercapacitor energy storage device through the ACDC charging device. The ACDC charging device control system collects the voltage across the energy storage device and charges the energy storage device through the constant current voltage limiting method and the constant voltage current limiting method. When the voltage across the energy storage device is equal to the rated voltage set for the DC bus, charging stops.

[0033] During the normal operation phase of the power grid, the power grid supplies power to the aircraft ground static variable power supply, and energy is supplied from the power grid to the aircraft via the static variable power supply;

[0034] In the low-voltage stage of the grid, the energy storage device supports the DC bus. When the load power is less than or equal to the power that the grid can provide, the load power is completely provided by the grid; when the load power is greater than the power that the grid can provide, the excess power is supplemented by the energy storage device.

[0035] When the power grid drops to 0, the power grid stops supplying power to the static variable power supply; the energy storage device supports the DC bus, and the energy is supplied from the energy storage device to the aircraft via the static variable power supply;

[0036] During the grid recovery phase, the grid is restored to supply power to the aircraft ground static variable power supply, the DC voltage and DC bus voltage at both ends of the energy storage device are collected, the DC bus capacitor is charged first, and then the ACDC charging device is controlled to charge the energy storage device;

[0037] During the equipment shutdown phase, the static variable power supply is shut down, and the energy storage device is disconnected from the DC bus of the static variable power supply;

[0038] In the supercapacitor self-recharging stage, the power grid normally supplies power to the aircraft ground static variable power supply. When the ACDC charging device control system detects that the difference between the DC bus voltage and the energy storage device voltage reaches a specified value, it controls the charging device to recharge the supercapacitor energy storage device.

[0039] During the equipment shutdown and maintenance phase, the power grid stops supplying power, disconnecting the energy storage device from the DC bus of the static transformer power supply.

[0040] Due to the adoption of the above technical solution, the present invention has the following advantages:

[0041] 1. Compared with the aircraft ground static variable power supply that uses batteries as energy storage devices, the present invention uses a supercapacitor energy storage device, which has the characteristics of high power density and high cycle life, small size, light weight, low cost and long life; compared with the aircraft ground static variable power supply that uses electrolytic capacitors as energy storage devices, the present invention has longer zero wear-through and low wear-through time, small size, light weight, low cost, and has better performance and practicality.

[0042] 2. Compared with the traditional uncontrolled rectification scheme, the present invention adopts active rectification topology and low-voltage control algorithm, which can greatly expand the DC bus voltage range, greatly reduce the configuration of the energy storage device, reduce the equipment volume, reduce weight, reduce costs, and have excellent practicality; without external energy storage devices, it can support the output of the power grid to the load at a lower voltage and realize the low voltage crossing function. Under the premise of external energy storage devices, when the power grid is low voltage, if the load power ≤ the power that the power grid can provide, the load power is completely provided by the power grid, which increases the service life of the energy storage device; when the load power is greater than the power that the power grid can provide, the excess part is provided by the energy storage device, making full use of the power grid and increasing the low-voltage crossing time. When the grid voltage is 0, the load power is completely provided by the energy storage device.

[0043] 3. The present invention adopts active rectification topology, which expands the range of DC bus voltage and can greatly reduce the configuration of supercapacitors; through the low voltage ride-through control algorithm, the low voltage ride-through function is realized. Different grid voltages can provide different powers. When the grid voltage is low, the grid supports the DC bus through active rectification, provides the load with grid power, and increases the low voltage ride-through time.

[0044] 4. The auxiliary power supply of the present invention adopts an integrated AC / DC input power supply. AC and DC power can be input independently and are internally isolated, which greatly increases the reliability of the auxiliary power supply and reduces the volume. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0046] Figure 1 A block diagram of an aircraft ground static variable power supply with battery energy storage in the prior art;

[0047] Figure 2 A block diagram of an aircraft ground static variable power supply with electrolytic capacitor energy storage in the prior art;

[0048] Figure 3 A block diagram of an aircraft ground static variable power supply with supercapacitor energy storage according to an embodiment of the present invention;

[0049] Figure 4 A topology diagram of an aircraft ground static variable power supply supporting zero wear and low wear in an embodiment of the present invention;

[0050] Figure 5 A schematic diagram of an energy storage system according to an embodiment of the present invention;

[0051] Figure 6 This is a flow chart of power-on control of an aircraft ground static variable power supply according to an embodiment of the present invention;

[0052] Figure 7 This is a control flow chart of supporting low wear and zero wear of power grid according to an embodiment of the present invention;

[0053] Figure 8 This is an energy transfer diagram when the power grid is normally powered according to an embodiment of the present invention;

[0054] Fig. 9 This is a power grid low voltage, load power ≤ power supply energy transfer diagram that the power grid can provide according to an embodiment of the present invention;

[0055] Fig.10 This is a power supply energy transfer diagram of a low power grid voltage and a load power>power that the power grid can provide according to an embodiment of the present invention;

[0056] Fig.11 This is an energy transfer diagram when the power grid has zero voltage according to an embodiment of the present invention;

[0057] Fig.12 It is an energy transfer diagram when the power grid resumes normal power supply according to an embodiment of the present invention;

[0058] Fig.13 This is a control block diagram of a static variable power supply according to an embodiment of the present invention. DETAILED DESCRIPTION

[0059] The present invention is further described in conjunction with the accompanying drawings and embodiments, and the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by ordinary technicians in this field should fall within the scope of protection of the embodiments of the present invention.

[0060] Traditional aircraft ground static power supplies consist of a grid-side rectifier module and a 115Vac / 400Hz side inverter module. The aircraft ground static power supply that supports zero wear is connected in parallel to the DC bus through an external energy storage system. When the grid is disconnected, the energy storage system supports the DC bus and supplies normal power to the aircraft through the inverter side.

[0061] Figure 1 The figure shows the traditional solution of adding battery energy storage to the aircraft ground static variable power supply. Batteries have high energy storage density and long life, which are suitable for application scenarios that require long-term stable energy output; but the power density is low. The grid flash interruption time is tens or hundreds of milliseconds, which is suitable for high-power density energy storage devices. However, the low power density of batteries requires over-matching of batteries, resulting in high cost, large size and heavy weight of the energy storage system. This solution is not cost-effective and difficult to popularize.

[0062] Figure 2 The figure shows the traditional solution of adding electrolytic capacitor energy storage to the aircraft ground static variable power supply. Electrolytic capacitors have high charge storage capacity and long life, and are suitable for high voltage and high current applications. However, the capacity of electrolytic capacitors is relatively small, suitable for occasions below 100ms. If the flash time increases, such as 500ms, the number of electrolytic capacitors needs to be greatly increased, resulting in high cost, large size, and heavy weight. This solution has low cost performance and is difficult to popularize.

[0063] Figure 3 The figure shows a zero-penetration aircraft ground static variable power supply with supercapacitor energy storage. Supercapacitors have both high power density and high cycle life, extremely fast charging and discharging speed, and power density of thousands of w / kg. They are more suitable for application scenarios that require instantaneous high power output and frequent charging and discharging at the same time, and have obvious advantages in energy storage situations of hundreds of ms to s. The supercapacitor solution is low in cost, small in size, and light in weight. This solution is very cost-effective and has good prospects for popularization.

[0064] See also Figure 3 , the present invention provides an embodiment of an aircraft ground static variable power supply supporting zero wear and low wear, which includes a main circuit, an energy storage system and an auxiliary power supply part;

[0065] The main circuit is composed of an input main switch, an ACDC (AC to DC) rectifier, a DCAC (DC to AC) inverter, and an output contactor connected in sequence. The input main switch and the output contactor can be controlled by the control system to realize the disconnection and closing functions. When the low-through or zero-through time exceeds the set value, or the DC bus is lower than the set value, the input main switch and the output contactor are disconnected; the ACDC rectifier adopts an active rectifier topology to convert the AC power of the power grid into high-voltage DC power;

[0066] The energy storage system consists of an auxiliary switch, an ACDC charging device, and a supercapacitor energy storage device connected in sequence; the AC power of the grid sequentially passes through the auxiliary switch and the ACDC charging device to supply power to the supercapacitor energy storage device, and the supercapacitor energy storage device supports the DC bus;

[0067] The auxiliary power supply part includes an isolation transformer and an AC / DC power supply; the AC power of the power grid is independently input into the AC / DC power supply after passing through the isolation transformer, and the high-voltage DC power of the DC bus is independently input into the AC / DC power supply to output low-voltage DC power.

[0068] In one embodiment of the present application, the ACDC rectifier includes an input circuit breaker, an AC inductor, an AC filter capacitor, a semiconductor rectifier, a grid-side DC bus capacitor, and a discharge resistor; the input circuit breaker is connected to the semiconductor rectifier through the AC inductor respectively; an AC filter capacitor is arranged between the input circuit breaker and the AC inductor; the semiconductor rectifier, the discharge resistor and the grid-side DC bus capacitor are connected in parallel.

[0069] Specifically, see Figure 4 The ACDC rectifier is composed of an input circuit breaker QF1, an AC inductor L, an AC filter capacitor C1, a semiconductor rectifier, a grid-side DC bus capacitor C2, and a discharge resistor R1; the input circuit breaker QF1 is connected to the semiconductor rectifier through the AC inductor L; an AC filter capacitor C1 is arranged between the input circuit breaker QF1 and the AC inductor L; the semiconductor rectifier, the discharge resistor R1 and the grid-side DC bus capacitor C2 are connected in parallel.

[0070] The function of the ACDC rectifier is to convert the 380Vac / 50Hz AC power of the power grid into high-voltage DC power. Among them, the semiconductor rectifier can adopt a three-phase active rectifier topology, and the DC bus voltage can be boosted to 700Vdc or even higher by alternating the conduction of the IGBT upper tubes V1, V3, V5 and the lower tubes V2, V4, V6, which is much larger than the approximately 540Vdc of the three-phase uncontrolled rectifier topology, and the DC bus voltage can be adjusted. The energy formula of the DC bus is:

[0071]

[0072] Where U max is the maximum DC bus voltage, U minIt is the lowest voltage that the DC bus can drop.

[0073] The DC bus voltage of the active rectification topology can reach 700V, which is much higher than the 540V of the uncontrolled rectification topology, and the minimum voltage can be basically the same; for occasions requiring the same energy, the active rectification topology can greatly reduce the energy of the supercapacitor module, reduce the number of supercapacitors, and significantly reduce costs. For occasions with the same capacitor configuration, active rectification can provide greater energy and greatly improve the zero wear time.

[0074] See also Figure 5 , the energy storage system includes a supercapacitor energy storage device, a charge and discharge control circuit, a sampling and controller, etc. The supercapacitor energy storage device includes a supercapacitor module, and its grouping method can be comprehensively determined based on the rated voltage of the DC bus, the cut-off voltage of the DC bus, the zero voltage support power and time, the external dimensions, weight, and cost. 58 3V360F monomers are welded in series on the PCB board to form a 174V6.2F standard energy storage module, and the energy storage system is composed of 5 174V6.2F standard energy storage modules. The maximum voltage of the energy storage system is 870V, and the capacitance value is 1.24F. The maximum voltage of the DC bus is set to 750V and the cut-off voltage is 400V. Considering the DC internal resistance of the supercapacitor, the voltage drop is about 50V, so the rated voltage of the DC bus is about 700V. The following table compares the zero penetration time of 0.86s and 2.2s when the rated voltage of the DC bus is 540V and 700V under the uncontrolled rectification and active rectification topologies, as shown in Table 1.

[0075] The zero-breakthrough time of the supercapacitor solution is much longer than the 0.2s that the traditional solution can achieve, which meets the customer's demand for long-term zero-voltage support of the power grid. At the same time, the zero-breakthrough time of the active rectification topology is nearly 3 times that of the uncontrolled rectification topology. Therefore, the effect of active rectification is significantly better than that of uncontrolled rectification, and the effect of active rectification + supercapacitor solution is better.

[0076] Table 1 Comparison of the effects of active rectification and uncontrolled rectification

[0077]

[0078] In this embodiment, the energy storage system includes a supercapacitor energy storage device and a charge and discharge control circuit; the charge and discharge control circuit is composed of a controllable discharge control circuit and a controllable charging circuit; the energy storage device is composed of a plurality of supercapacitor modules connected in series; the energy storage device is arranged between the controllable discharge control circuit and the controllable charging circuit;

[0079] The controllable discharge control circuit includes a discharge diode, a fuse, a first discharge control switch, a discharge main switch, and a second discharge control switch; the discharge diode, the fuse, the first discharge control switch, and the discharge main switch are connected in series in sequence, and the discharge main switch is connected to the positive electrode of the DC bus capacitor; the positive electrode of the discharge diode is connected to the positive electrode of the energy storage device, and the negative electrode is connected to the fuse; one end of the second discharge control switch is connected to the negative electrode of the energy storage device, and the other end is connected to the negative electrode of the DC bus capacitor;

[0080] The controllable charging device includes a charging protection circuit breaker, a third charging control switch and an ACDC charging device connected in sequence; the charging protection circuit breaker protects the charging circuit and serves as a maintenance switch; the third charging control switch controls the power on of the charging circuit.

[0081] In one embodiment of the present application, the diode is used for unidirectional discharge; the fuse plays a protective role when the system is short-circuited or severely overloaded; the first discharge control switch and the second discharge control switch are controllable switches to disconnect the energy storage system from the DC bus to achieve safety protection; the main discharge switch uses a circuit breaker as a breakpoint and line protection;

[0082] The energy storage device can be charged by an ACDC charging device, which draws power from the grid, or by a DCDC charging module, which draws power from the DC bus.

[0083] Specifically, see Figure 5 The controllable discharge control circuit includes a discharge diode D1, a fuse FU1, discharge control switches KA1 and KA2, and a discharge main switch QF2. The diode D1 is a unidirectional device that performs a unidirectional discharge function. The fuse FU1 protects the system when it is short-circuited or severely overloaded. The discharge control switches KA1 and KA2 are controllable switches that can disconnect the energy storage system from the DC bus to achieve safety protection. The discharge main switch QF2 uses a circuit breaker as a breakpoint and line protection for easy maintenance.

[0084] The controllable charging device of the energy storage system includes a charging protection circuit breaker QF3, a charging control switch KA3, and a charging device. The charging protection circuit breaker QF3 protects the charging circuit and serves as a switch for maintenance; the charging control switch KA3 controls the power on of the charging circuit; charging devices of different power levels can be configured according to the different requirements of the system for charging time, with high power and fast charging time. Among them, the energy storage device can be charged by an ACDC charging device to draw power from the grid side, or by a DCDC charging module to draw power from the DC bus. In this embodiment, a 15kW AC / DC charging device is used. When the energy storage device is powered on for the first time, the charging device can charge the energy storage device by a constant current limiting method, and when it is close to full, a constant voltage limiting method is used for charging. Due to the high self-discharge rate of supercapacitors, the use of appropriate charging control methods can improve the life of supercapacitor energy storage devices and the stability of the system. Compared with the traditional charging scheme using a current limiting resistor, the controllable charging device scheme has a fast charging speed, very low loss, and better adaptability.

[0085] In one embodiment of the present application, the energy storage system also includes a sampling and controller; the sampling and controller is used to collect the total voltage and total current of the energy storage device and the voltage of a single supercapacitor module, and feed them back to the aircraft ground static variable power supply control system to control the charging and discharging of the energy storage device and protect it.

[0086] In one embodiment of the present application, the inverter module (DCAC inverter) includes an inverter-side bus capacitor, a bus discharge resistor, a three-phase full-bridge inverter unit, and an isolation transformer T; the inverter-side bus capacitor, the bus discharge resistor, and the three-phase full-bridge inverter unit are connected in parallel; one side of the isolation transformer is connected to the three-phase full-bridge inverter unit; and the other side of the isolation transformer is connected to the filter capacitor C22. The inverter module converts high-voltage direct current into 115Vac / 400Hz alternating current to power the aircraft.

[0087] The present invention also provides an embodiment of a control method for an aircraft ground static variable power supply supporting zero wear and low wear, which is applicable to the aircraft ground static variable power supply supporting zero wear and low wear described in the above embodiment, and comprises:

[0088] The energy storage system supports the DC bus to achieve zero wear;

[0089] When the grid voltage is low, the grid supports the DC bus through active rectification and provides the grid's electric energy to the load. When the load power is less than or equal to the power that the grid can provide, the load power is completely provided by the grid, and the active rectification output voltage is increased to be greater than the rated voltage of the DC bus capacitor. When the load power is greater than the power that the grid can provide, the load power is provided by the grid, and the part of the load power that exceeds the power that the grid can provide is provided by the energy storage device. At this time, the active rectification output voltage is adjusted to be equal to the rated voltage of the DC bus capacitor and decreases as the bus voltage drops. When the grid voltage is zero, the load power is completely provided by the energy storage device.

[0090] The present invention adopts an active rectification topology, which expands the range of the DC bus voltage and can significantly reduce the configuration of the supercapacitor; through the low voltage ride-through control algorithm, the load power can be completely provided by the power grid, or the load power can be provided by the power grid and the energy storage device, which greatly improves the low voltage ride-through time.

[0091] In one embodiment of the present application, an active rectification topology and a low voltage control algorithm are used to achieve bus voltage stability: the currently required active current is calculated, the active current component is added to the control loop, and the IGBT switching action is driven with different duty cycles through PWM modulation to achieve bus voltage stability;

[0092] Specifically, see Fig.13 , calculate the current required active current

[0093]

[0094] Among them, P out is the current output power (this device is a voltage source, and its output power is determined by the load), V amp is the current grid voltage amplitude.

[0095] Fig.13 middle, is the bus voltage setting value, U dc is the bus voltage feedback value, is the active current setting value, i sq is the active current feedback value, is the reactive current setting value, i sd is the reactive current feedback value, PI is the PI controller, θ is the grid voltage phase angle, T 2r / 2s is the park inverse transformation matrix.

[0096] In one embodiment of the present application, when the load power is constant, under different grid voltages, the IGBT duty cycle is adjusted through the low voltage ride-through technology to achieve stability of the DC bus voltage within a certain period of time, thereby achieving low voltage ride-through functions of different durations under fixed load power levels and different grid voltages.

[0097] When the grid low voltage is constant and the load power is different, the low voltage ride-through technology is used to adjust the IGBT duty cycle to achieve the stability of the DC bus voltage within a certain period of time. The low voltage ride-through function of different durations can be achieved under the fixed low voltage of the grid and different load power levels.

[0098] When the load power is less than or equal to the power that the grid can provide, the load power is completely provided by the grid; at this time, the low-breakthrough time t is infinite in theory.

[0099] When the load power is greater than the power that the grid can provide, the excess is provided by the energy storage device, which greatly increases the low penetration support time. The aircraft ground static variable power supply has overload capacity, 1.25 times overload for 600s, 1.5 times overload for 60s, 2 times overload for 30s, 3 times overload for 10s, 4 times overload for 1s.

[0100] The maximum support time for low penetration is t:

[0101]

[0102] Where, t is the maximum support time of low penetration, k is the overload coefficient, P g is the rated power at the current voltage, t g is the overload time, U max is the maximum DC bus voltage, U min It is the lowest voltage that the DC bus can drop, and P0 is the load power.

[0103] See also Figure 6 and Figure 7 The present invention also provides an embodiment of a working method of an aircraft ground static variable power supply supporting zero penetration and low penetration, which is applicable to the aircraft ground static variable power supply supporting zero penetration and low penetration described in the above embodiment, and comprises:

[0104] During the first power-on phase of the grid, the grid charges the bus capacitor through the aircraft ground static variable power grid side pre-charging unit. When the DC bus voltage U dc =U dc_e -U m When (in the formula, U dc_e is the rated voltage, U mis a constant greater than or equal to 0. According to the system settings, the main switch QF1 on the grid side is closed and the pre-charging switch on the grid side is disconnected. At the same time, QF2, QF3 and the charging control switch KA3 are closed. The grid charges the supercapacitor energy storage device through the AC / DC charging device. The charging device control system collects the voltage U on both sides of the energy storage device. c_dc , the energy storage device is charged by the constant current limiting voltage method and the constant voltage limiting current method. dc_e -U c_dc =U n When KA3 is disconnected, charging stops (U n is a constant greater than or equal to 0. According to the system settings, KA1 and KA2 are closed. Compared with the traditional passive charging scheme using a current limiting resistor, the charging voltage of the active charging scheme using a charging device is adjustable. If a higher charging voltage is set, the charging voltage of the DC bus is also high; at the same time, the charging speed is fast and the loss is very small. At this time, the state of the switch: QF1, QF2, QF3 are closed, KA1 and KA2 are closed, and KA3 is open.

[0105] The grid is in the normal working stage. The grid supplies power to the aircraft ground static variable power supply, and the energy is supplied to the aircraft from the grid through the static variable power supply. At this time, the aircraft ground static variable power supply control system collects the voltage and current of the load in real time, obtains the load power P0, and the DC bus set voltage U dc With load power P n The relationship is (U dc The unit is V, P n The unit is kW). Through the control strategy, the device is controlled to reduce the DC bus voltage when the load is low, improve the system efficiency, and increase the DC bus voltage when the load is high to improve the load capacity of the device. At this time, the switch status: QF1, QF2, QF3 are closed, KA1 and KA2 are closed, and KA3 is open.

[0106] The grid is in a low voltage stage. The energy storage device supports the DC bus. At the same time, the grid provides energy through active rectification. If the load power is ≤ the power that the grid can provide, the load power is completely provided by the grid; when the load power is greater than the power that the grid can provide, the excess is provided by the energy storage device, making full use of the grid power. At this time, the switch status: QF1, QF2, QF3 are closed, KA1 and KA2 are closed, and KA3 is open.

[0107] The grid drops to 0. The grid stops supplying power to the static variable power supply; the supercapacitor energy storage device supports the DC bus, and the energy is supplied from the energy storage device to the aircraft via the static variable power supply. DC bus voltage U dc , the voltage U of the energy storage device c_dc At this time, the switch status is: QF1, QF2, QF3 are closed, KA1 and KA2 are closed, and KA3 is open.

[0108] Grid recovery phase. The grid is restored in a very short time (depending on the specific situation of the airport, such as 200ms), and the grid is restored to supply power to the aircraft ground static power supply. Since the DC bus voltage drops at this time, the DC bus voltage U dc <<U dc_e At the moment of grid recovery, the DC bus voltage rises to U dc_e , will bring a greater impact to the static transformer power supply AC main switch, grid-side semiconductor devices, etc., and in severe cases may damage the devices. dc Than U dc_e The lower it is, the greater the impact is, so the cut-off voltage U of zero voltage crossing is dc_min It cannot be too low. The control system collects the DC voltage and DC bus voltage of the energy storage device and controls the charging device to charge the energy storage device. At this time, the status of the switch: QF1, QF2, QF3 are closed, KA1 and KA2 are closed, and KA3 is closed.

[0109] Equipment shutdown stage. The static variable power supply is shut down, and the energy storage system switches KA1 and KA2 are disconnected, and the energy storage device is disconnected from the static variable power supply DC bus. At this time, the switch status is: QF1 is disconnected, QF2 is closed, KA1 and KA2 are disconnected, and KA3 is disconnected.

[0110] Supercapacitor self-recharge stage. The power grid normally supplies power to the aircraft ground static variable power supply. Due to the high self-discharge rate of the supercapacitor, the voltage of the energy storage device drops. When the ACDC charging device control system detects that the difference between the DC bus voltage and the energy storage device voltage reaches the specified value, that is, U dc -U c_dc =U m , control the charging device to recharge the supercapacitor. m It is a number greater than 0, which is determined by the self-discharge rate of the supercapacitor. At this time, the switch states are: QF1 is closed, QF2 is closed, KA1 and KA2 are closed, and KA3 is closed.

[0111] Equipment shutdown maintenance phase. The power grid stops supplying power. To ensure the safety of maintenance personnel, QF2 is disconnected to disconnect the energy storage system from the DC bus of the static transformer power supply. At this time, the switch status is: QF1 is disconnected, QF2 is disconnected, QF3 is disconnected, KA1 and KA2 are disconnected, and KA3 is disconnected.

[0112] Figure 8 This is an energy transfer diagram when the power grid is normally powered according to an embodiment of the present invention; Fig. 9 This is a power grid low voltage, load power ≤ power supply energy transfer diagram that the power grid can provide according to an embodiment of the present invention; Fig.10 This is a power supply energy transfer diagram of a low power grid voltage and a load power>power that the power grid can provide according to an embodiment of the present invention; Fig.11 This is an energy transfer diagram when the power grid has zero voltage according to an embodiment of the present invention; Fig.12This is an energy transfer diagram when the power grid resumes normal power supply according to an embodiment of the present invention.

[0113] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. An aircraft ground static variable power supply supporting zero wear and low wear, characterized in that: Including main circuit, energy storage system and auxiliary power supply; The main circuit is composed of an input main switch, an ACDC rectifier, a DCAC inverter, and an output contactor connected in sequence. The input main switch and the output contactor can be controlled by the control system to realize the disconnection and closing functions. When the low-through or zero-through time exceeds the set value, or the DC bus voltage is lower than the set value, the input main switch and the output contactor are disconnected; the ACDC rectifier adopts an active rectifier topology to convert the AC power of the power grid into high-voltage DC power; The energy storage system consists of an auxiliary switch, an ACDC charging device, a supercapacitor energy storage device, and a discharge diode connected in sequence; the AC power of the grid sequentially passes through the auxiliary switch and the ACDC charging device to supply power to the supercapacitor energy storage device, and the supercapacitor energy storage device supports the DC bus through the discharge diode; The auxiliary power supply part includes an isolation transformer and an AC / DC power supply; the AC power of the power grid is independently input into the AC / DC power supply after passing through the isolation transformer, and the high-voltage DC power of the DC bus is independently input into the AC / DC power supply to output low-voltage DC power.

2. The aircraft ground static variable power supply supporting zero wear and low wear according to claim 1, characterized in that: The ACDC rectifier includes an input circuit breaker, an AC inductor, an AC filter capacitor, a semiconductor rectifier, a grid-side DC bus capacitor, and a discharge resistor; the input circuit breaker is connected to the semiconductor rectifier through the AC inductor respectively; an AC filter capacitor is arranged between the input circuit breaker and the AC inductor; the semiconductor rectifier, the discharge resistor and the grid-side DC bus capacitor are connected in parallel.

3. The aircraft ground static variable power supply supporting zero wear and low wear according to claim 1, characterized in that: The energy storage system includes a charge and discharge control circuit and a supercapacitor energy storage device; the charge and discharge control circuit is composed of a controllable discharge control circuit and a controllable charging circuit; the supercapacitor energy storage device is composed of a plurality of supercapacitor modules connected in series in sequence; the supercapacitor energy storage device is arranged between the controllable discharge control circuit and the controllable charging circuit; The controllable discharge control circuit includes a discharge diode, a fuse, a first discharge control switch, a discharge main switch, and a second discharge control switch; the discharge diode, the fuse, the first discharge control switch, and the discharge main switch are connected in series in sequence, and the discharge main switch is connected to the positive electrode of the DC bus capacitor; the positive electrode of the discharge diode is connected to the positive electrode of the energy storage device, and the negative electrode is connected to the fuse; one end of the second discharge control switch is connected to the negative electrode of the energy storage device, and the other end is connected to the negative electrode of the DC bus capacitor; The controllable charging device includes a charging protection circuit breaker, a third charging control switch and an ACDC charging device connected in sequence; the charging protection circuit breaker protects the charging circuit and serves as a maintenance switch; the third charging control switch controls the power on of the charging circuit.

4. The aircraft ground static variable power supply supporting zero wear and low wear according to claim 3, characterized in that: The diode is used for unidirectional discharge; the fuse plays a protective role when the system is short-circuited or severely overloaded; the first discharge control switch and the second discharge control switch are controllable switches to disconnect the energy storage system from the DC bus to achieve safety protection; the main discharge switch uses a circuit breaker as a breakpoint and line protection; The energy storage device can be charged by an ACDC charging device, which draws power from the grid, or by a DCDC charging device, which draws power from the DC bus.

5. The aircraft ground static variable power supply supporting zero wear and low wear according to claim 3, characterized in that: The energy storage system also includes a sampling and controller; The sampling and controller is used to collect the total voltage and total current of the energy storage device and the voltage of a single supercapacitor module, and feed it back to the control system of the aircraft ground static variable power supply to control and protect the charging and discharging of the energy storage device.

6. The aircraft ground static variable power supply supporting zero wear and low wear according to claim 1, characterized in that: The DCAC inverter includes an inverter-side bus capacitor, a bus discharge resistor, a three-phase full-bridge inverter unit and an isolation transformer; the inverter-side bus capacitor, the bus discharge resistor and the three-phase full-bridge inverter unit are connected in parallel; one side of the isolation transformer is connected to the three-phase full-bridge inverter unit; and the other side of the isolation transformer is connected to the filter capacitors respectively.

7. A control method for an aircraft ground static variable power supply supporting zero penetration and low penetration, applicable to the aircraft ground static variable power supply supporting zero penetration and low penetration as claimed in any one of claims 1 to 6, characterized in that: include: The energy storage system supports the DC bus to achieve zero wear; When the grid voltage is low, the grid supports the DC bus through active rectification to provide the load with grid power. When the load power is less than or equal to the power that the grid can provide, the load power is completely provided by the grid, and the active rectification output voltage is increased to be greater than the rated voltage of the DC bus. When the load power is greater than the power that the grid can provide, the load power is provided by the grid, and the part of the load power that exceeds the power that the grid can provide is provided by the energy storage system. At this time, the active rectification output voltage is adjusted to be equal to the rated voltage of the DC bus, and decreases as the DC bus voltage drops. When the grid voltage is zero, the load power is completely provided by the energy storage system.

8. The method according to claim 7, characterized in that Calculate the currently required active current, add the active current component to the control loop, and drive the IGBT switch action with different duty cycles through PWM modulation to achieve DC bus voltage stability; When the load power is fixed, under different grid voltages, the IGBT duty cycle is adjusted through low voltage ride-through technology to achieve DC bus voltage stability within a specified time; When the grid voltage is fixed at low level and the load power is different, the IGBT duty cycle is adjusted through low voltage ride-through technology to achieve stability of the DC bus voltage within a specified time.

9. The method according to claim 8, characterized in that The maximum support time of low voltage ride-through is: Where, t is the maximum support time of low penetration, k is the overload coefficient, P g is the rated power at the current voltage, t g is the overload time, U max is the maximum DC bus voltage, U min It is the lowest voltage that the DC bus can drop, and P0 is the load power.

10. A method for operating an aircraft ground static variable power supply supporting zero penetration and low penetration, applicable to the aircraft ground static variable power supply supporting zero penetration and low penetration as claimed in any one of claims 1 to 6, characterized in that: include: During the first power-on phase of the power grid, the power grid pre-charges the DC bus capacitor through the pre-charging circuit, and then closes the input main switch of the aircraft ground static variable power supply to start the ACDC rectifier. When the DC bus voltage is equal to the set rated voltage, the power grid charges the supercapacitor energy storage device through the ACDC charging device. The ACDC charging device control system collects the voltage across the energy storage device and charges the energy storage device through the constant current voltage limiting method and the constant voltage current limiting method. When the voltage across the energy storage device is equal to the rated voltage set for the DC bus, charging stops. During the normal operation phase of the power grid, the power grid supplies power to the aircraft ground static variable power supply, and energy is supplied from the power grid to the aircraft via the static variable power supply; In the low-voltage stage of the grid, the energy storage device supports the DC bus. When the load power is less than or equal to the power that the grid can provide, the load power is completely provided by the grid; when the load power is greater than the power that the grid can provide, the excess power is supplemented by the energy storage device. When the power grid drops to 0, the power grid stops supplying power to the static variable power supply; the energy storage device supports the DC bus, and the energy is supplied from the energy storage device to the aircraft via the static variable power supply; During the grid recovery phase, the grid is restored to supply power to the aircraft ground static variable power supply, the DC voltage and DC bus voltage at both ends of the energy storage device are collected, the DC bus capacitor is charged first, and then the ACDC charging device is controlled to charge the energy storage device; During the equipment shutdown phase, the static variable power supply is shut down, and the energy storage device is disconnected from the DC bus of the static variable power supply; In the supercapacitor self-recharging stage, the power grid normally supplies power to the aircraft ground static variable power supply. When the ACDC charging device control system detects that the difference between the DC bus voltage and the energy storage device voltage reaches a specified value, it controls the charging device to recharge the supercapacitor energy storage device. During the equipment shutdown and maintenance phase, the power grid stops supplying power, disconnecting the energy storage device from the DC bus of the static transformer power supply.

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