Oht wireless power supply system and regenerative energy multiplexing control method

Abstract

The present application belongs to the technical field of dynamic wireless power transmission, and particularly relates to an OHT wireless power supply system and a regenerative energy multiplexing control method. The system comprises a primary side transmitting end and at least two OHT vehicle end receiving units. The primary side transmitting end comprises a primary side full-bridge inverter and a transmitting coil. The OHT vehicle end receiving unit comprises a receiving coil, a receiving side active full-bridge and a vehicle end DC bus. The primary side full-bridge inverter is connected with the transmitting coil, and the transmitting coil is coupled with the receiving coil. The AC side of the receiving side active full-bridge is connected with the receiving coil, and the DC side of the receiving side active full-bridge is connected with the vehicle end DC bus. The receiving side active full-bridge is a bidirectional full-bridge converter. The present application avoids the regenerative power from being back-feeding into the primary side DC power supply or the DC bus, forms a multi-level power coordination and protection mechanism, improves the controllability of the system operation boundary, and reduces the invalid consumption of the braking energy.

Description

Technical Field

[0001] This invention belongs to the field of dynamic wireless power transmission technology, and particularly relates to OHT wireless power supply system and regenerative energy reuse control method. Background Technology

[0002] OHT vehicles frequently undergo acceleration, constant speed, turning, stopping, and braking processes in environments such as semiconductor cleanrooms. Due to the high requirements of cleanrooms regarding particle control, heat, and maintenance complexity, traditional on-board batteries, sliding contact power supplies, or simple braking resistors have limitations in terms of continuous operation, maintenance, and thermal management.

[0003] Regionalized wireless power supply tracks can provide contactless power to OHT vehicles, but existing systems typically treat the receiver as a unidirectional energy harvester. Regenerative energy generated during vehicle braking is often consumed by the vehicle-end braking resistor or temporarily stored in the vehicle-end energy storage device. For OHT vehicles, the braking process is short-lived, and both braking and traction vehicles may exist simultaneously within the same power supply zone. Therefore, if the regenerative energy of the braking vehicle can be transferred to the traction vehicle in real time via a shared track, braking energy consumption and peak power demand on the primary side can be reduced.

[0004] However, directly requiring the primary-side inverter to participate in bidirectional feedback would alter the topology and protection boundaries of the primary-side power supply area, increasing the complexity of system modification. Therefore, an OHT wireless power supply solution is needed that allows energy injection, energy absorption, and power coordination to be completed by a vehicle-side bidirectional active pickup while maintaining unidirectional high-frequency excitation on the primary side. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, this invention provides an OHT wireless power supply system and a regenerative energy reuse control method. Without changing the primary side unidirectional excitation topology, the braking regenerative power is preferentially absorbed by traction or heavy-load vehicles in the same power supply area of ​​the shared track. The residual power that is not absorbed is processed through power limiting commands or residual absorption branches, avoiding the regenerative power from flowing back into the primary side DC power supply or DC bus. This forms a multi-level power coordination and protection mechanism, improves the controllability of the system operating boundary, and reduces the ineffective consumption of braking energy.

[0006] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions: The first aspect of this invention provides an OHT wireless power supply system.

[0007] An OHT wireless power supply system includes a primary-side transmitter and at least two OHT vehicle-side receiver units. The primary-side transmitter includes a primary-side full-bridge inverter and a transmitting coil. The OHT vehicle-side receiver unit includes a receiving coil, a receiving-side active full-bridge inverter, and a vehicle-side DC bus. The primary-side full-bridge inverter is connected to the transmitting coil, and the transmitting coil is coupled to the receiving coil. The AC side of the receiving-side active full-bridge inverter is connected to the receiving coil, and the DC side of the receiving-side active full-bridge inverter is connected to the vehicle-side DC bus. The receiving-side active full-bridge inverter is a bidirectional full-bridge converter.

[0008] As an optional technical solution, the primary-side transmitter also includes a primary-side power supply component and a primary-side LCC compensation network. The primary-side power supply component is a primary-side DC power supply or a DC bus. The primary-side power supply component is connected to the primary-side full-bridge inverter, and the primary-side full-bridge inverter is connected to the transmitting coil through the primary-side LCC compensation network.

[0009] As an optional technical solution, each of the OHT vehicle-side receiving units is installed on an OHT vehicle, and multiple OHT vehicles are installed on a shared track; the OHT vehicle-side receiving unit also includes a receiving-side S-compensation network and a vehicle-side load port; the AC side of the receiving-side active full-bridge is connected to the receiving coil through the receiving-side S-compensation network, and the vehicle-side load port is connected to the vehicle-side DC bus; the vehicle-side load port includes a motor drive port, a vehicle-side DC load, and a braking energy port.

[0010] As an alternative technical solution, a coordination controller is also included. The coordination controller is used to adjust the phase relationship between the AC terminal fundamental voltage of the receiving active full bridge and the induced voltage of the receiving coil, thereby switching the positive reflection impedance mode and the negative reflection impedance mode of the OHT vehicle-end receiving unit.

[0011] As an alternative technical solution, the coordination controller is used to control the corresponding receiving side active full bridge to enter the negative reflective impedance mode when the OHT vehicle is in a braking state, so that the OHT vehicle injects regenerative power into the shared track; when the OHT vehicle is in a traction or heavy load state, it controls the corresponding receiving side active full bridge to enter the positive reflective impedance mode, so that the OHT vehicle absorbs power from the shared track.

[0012] As an alternative technical solution, the coordination controller is also used to determine the primary-side non-reverse injection constraint and calculate the upper limit of the allowable injection power: OHT vehicles that are in braking condition and have injectable regenerative power are classified into the injection set, and OHT vehicles that are in traction or heavy load condition and have absorbable power requirements are classified into the absorption set. The sum of the absorbable power of the absorbing set and the track loss is calculated, and the upper limit of the allowable injected power is determined after deducting the non-negative safety margin, and the upper limit of the allowable injected power is not less than zero. After obtaining the maximum allowed injected power, the coordination controller is further configured to: Based on the upper limit of the allowed injected power and the absorbable power of the absorption set, the injected power reference for the braking vehicle and the absorbed power reference for the traction vehicle are generated respectively. When the DC bus voltage at the vehicle end exceeds a preset threshold, or when the injectable regenerative power exceeds the upper limit of the allowable injectable power, the control will reduce the injectable power reference or enable the residual absorption branch.

[0013] As an alternative technical solution, the coordination controller is also used to calculate the fundamental output amplitude and phase of the active full-bridge on the receiving side based on the vehicle-end power reference, the vehicle-end DC bus voltage, and the mutual inductance or coupling parameters of the receiving coil and the transmitting coil.

[0014] The second aspect of this invention provides a method for controlling the regenerative energy reuse of an OHT wireless power supply system.

[0015] The regenerative energy reuse control method for OHT wireless power supply systems includes the following steps: Define the area, identify the vehicles within the same area, and determine whether the vehicles within the same area are in a tractor-trailer, heavily loaded, unloaded, or braking state. Calculate the injectable regenerative power of the vehicle under braking conditions; Calculate the absorbable power of the vehicle under traction conditions; Based on the injectable regenerative power of the vehicle in braking state and the absorbable power of the vehicle in traction state, determine whether the primary-side non-reverse flow constraint is satisfied. When the primary side non-reverse flow constraint is satisfied, the orbital side injected power reference and absorbed power reference are allocated; The output amplitude and phase of the active full-bridge receiver are calculated based on the power reference. Control the braking vehicle to enter negative reflective impedance mode and control the traction vehicle to enter positive reflective impedance mode; Determine if the DC bus at the vehicle end is overvoltage, and if so, reduce the injected power reference or enable the residual absorption branch.

[0016] As an alternative technical solution, the original edge non-reverse irrigation constraint is: The total injection power of the injection set within the same region is not greater than the sum of the total absorption power of the absorption set and the track loss minus the non-negative safety margin, and the difference is not less than zero.

[0017] As an alternative technical solution, when the injectable regenerative power of the braking vehicle is greater than the absorbable power of the traction vehicle, the absorbable portion is preferentially allocated to the traction vehicle, and the remaining portion is reduced in power through power limiting command or allocated to the residual absorption branch.

[0018] The above one or more technical solutions have the following beneficial effects: This invention provides an OHT wireless power supply system and a regenerative energy reuse control method. While maintaining the unidirectional high-frequency excitation mode of the primary-side full-bridge inverter, a coordinated controller coordinates and controls the fundamental output amplitude and phase of the active full-bridge inverter at each vehicle end receiving side. This causes braking vehicles to exhibit negative reflective impedance and inject regenerative power into the shared track, while traction or heavy-load vehicles exhibit positive reflective impedance and absorb power from the shared track. Simultaneously, a primary-side non-reverse-feedback constraint ensures the system's operational safety boundary. Real-time reuse of OHT braking energy on the track side can be achieved without altering the primary-side unidirectional excitation topology.

[0019] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0020] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the 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.

[0021] Figure 1 This is a schematic diagram of the equivalent circuit of the OHT wireless power supply system in an embodiment of the present invention.

[0022] Figure 2 This is a block diagram of the coordinated control of regenerative energy reuse in Embodiment 1 of the present invention.

[0023] Figure 3 This is a flowchart of the regenerative energy reuse control method in Embodiment 2 of the present invention.

[0024] Explanation of reference numerals in the attached figures: 101. Primary-side DC power supply / DC bus; 102. Primary-side full-bridge inverter; 103. Primary-side LCC compensation network; 104. Transmitting coil; 105. First magnetic coupling channel / first mutual inductance; 106. First receiving coil; 107. First receiving-side S-compensation network; 108. First receiving-side active full-bridge; 109. First vehicle-side DC bus / filter capacitor; 110. First vehicle-side load; 111. Second magnetic coupling channel / second mutual inductance; 112. Second receiving coil; 113. Second receiving-side S-compensation network ; 114. Second receiving side active full bridge; 115. Second vehicle-end DC bus / filter capacitor; 116. Second vehicle-end load; 301. Vehicle status identification unit; 302. Sampling unit; 303. Traction power demand calculation unit; 304. Regenerative power calculation unit; 305. Injected / absorbed vehicle classification unit; 306. Primary side non-reverse flow constraint unit; 307. Power reference allocation unit; 308. Amplitude and phase generation unit; 309. Active full bridge drive unit; 310. Overvoltage / residual power protection unit. Detailed Implementation

[0025] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0026] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations of the present invention.

[0027] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0028] Example 1 In an embodiment of the present invention: OHT (Overhead Hoist Transport) refers to unmanned transport vehicles that run along suspended tracks in scenarios such as semiconductor cleanrooms. Its operating states include four typical states: traction, heavy load, no load, and braking.

[0029] Reflection impedance refers to the impedance that the receiving circuit presents on the transmitting side through magnetic coupling. When the real part of the equivalent impedance on the receiving side is positive, it is called positive reflection impedance mode, in which the receiving side absorbs power from the shared track. When the real part of the equivalent impedance on the receiving side is negative, it is called negative reflection impedance mode, in which the receiving side injects power into the shared track.

[0030] LCC compensation network refers to an LCC-type resonant compensation network composed of inductors and capacitors, used to achieve constant current excitation characteristics on the primary side.

[0031] The S-compensation network is a series compensation network, including a compensation capacitor connected in series between the receiving coil and the AC terminal of the active full-bridge on the receiving side; the compensation capacitor and the receiving coil form a series resonant branch near the target operating frequency, and the series resonant branch also includes the equivalent resistance of the receiving coil and the connecting lines.

[0032] Existing OHT wireless power supply systems typically treat the receiver as a unidirectional energy extraction point. The regenerative energy generated during vehicle braking can only be consumed by the vehicle-side braking resistor or temporarily stored in the vehicle-side energy storage device, and cannot be absorbed in real time by traction or heavy-load vehicles within the same power supply area. To achieve regenerative energy feedback, the primary-side inverter needs to participate in bidirectional feedback, which leads to changes in the topology and protection boundaries of the primary-side power supply area, resulting in high system modification complexity and the risk of regenerative power flowing back into the primary-side DC power supply or DC bus.

[0033] To address the aforementioned issues, this invention provides an OHT wireless power supply system based on a bidirectional active pickup. While maintaining the unidirectional high-frequency excitation mode of the primary-side full-bridge inverter, a coordination controller coordinates and controls the fundamental output amplitude and phase of the active full-bridge inverter at each vehicle end. This causes braking vehicles to exhibit negative reflective impedance and inject regenerative power into the shared track, while traction or heavy-load vehicles exhibit positive reflective impedance and absorb power from the shared track. Simultaneously, primary-side non-reverse power injection constraints ensure the system's operational safety boundaries. This allows for real-time multiplexing of OHT braking energy on the track side without altering the primary-side unidirectional excitation topology.

[0034] like Figure 1 As shown, the OHT wireless power supply system includes a primary-side DC power supply or DC bus, a primary-side full-bridge inverter, a primary-side LCC compensation network, a transmitting coil, at least two OHT vehicle-side receiving units, and a coordination controller; each OHT vehicle-side receiving unit includes a receiving coil, a receiving-side S-compensation network, a receiving-side active full-bridge, a vehicle-side DC bus, and a vehicle-side load port.

[0035] In the OHT regional wireless power supply system, this invention enables the regenerative energy of braking vehicles to be absorbed in real time by traction or heavy-load vehicles in the same area through a shared track, while avoiding the backflow of regenerative power into the primary DC power supply or DC bus, and at the same time maintaining the unidirectional high-frequency excitation mode of the primary full-bridge inverter.

[0036] In the context of braking vehicles, traction vehicles, and heavy-load vehicles, "braking," "traction," and "heavy-load" refer to the vehicle's state. A braking vehicle is a vehicle in a braking state, a traction vehicle is a vehicle in a traction state, and a heavy-load vehicle is a vehicle in a heavy-load state.

[0037] Specifically: The primary-side full-bridge inverter is connected to the transmitting coil through the primary-side LCC compensation network, and the primary-side full-bridge inverter provides unidirectional high-frequency excitation to the transmitting coil through the primary-side LCC compensation network; The transmitting coil is coupled to the receiving coil; The AC side of the receiving-side active full-bridge is connected to the receiving coil through the receiving-side S-compensation network, the DC side of the receiving-side active full-bridge is connected to the vehicle-end DC bus, and the vehicle-end load port is connected to the vehicle-end DC bus; the vehicle-end load port includes a motor drive port, a vehicle-end DC load, and a braking energy port. The receiving-side active full-bridge converter is a bidirectional full-bridge converter, whose AC side is connected to the receiving-side S-compensation network, and whose DC side is connected to the vehicle-end DC bus. The coordination controller is used to switch the positive reflection impedance mode and the negative reflection impedance mode of the OHT vehicle-end receiving unit by adjusting the phase relationship between the AC terminal fundamental voltage of the receiving active full bridge and the induced voltage of the receiving coil.

[0038] Furthermore: The coordination controller controls the fundamental output amplitude and phase of the corresponding active full-bridge receiver based on the traction, heavy load, no load, or braking status of each OHT vehicle within the same power supply area. This causes the OHT vehicle in the braking state to exhibit negative reflective impedance through its active full-bridge receiver and inject regenerative power into the shared track where the transmitting coil is located. Conversely, the OHT vehicle in the traction or heavy load state causes it to exhibit positive reflective impedance through its active full-bridge receiver and absorb power from the shared track.

[0039] In this embodiment, "same power supply area" refers to the track coverage area formed by the same primary-side full-bridge inverter, primary-side LCC compensation network and its corresponding transmitting coil, which is excited by high frequency; multiple OHT vehicle-end receiving units located in this area and effectively magnetically coupled to the transmitting coil share the same track power channel.

[0040] The primary-side full-bridge inverter provides unidirectional high-frequency excitation to the transmitting coil through the primary-side LCC compensation network. The receiving-side active full-bridge generates a controllable fundamental voltage at the AC terminal of the receiving coil through amplitude and phase modulation. When the vehicle is braking, the coordination controller puts the corresponding receiving-side active full-bridge into negative reflective impedance mode, allowing the vehicle to inject regenerative power into the shared track; when the vehicle is traction or heavily loaded, the coordination controller puts the corresponding receiving-side active full-bridge into positive reflective impedance mode, allowing the vehicle to absorb power from the shared track.

[0041] The positive and negative reflection impedance modes are distinguished by the sign of the real part of the equivalent reflection impedance Zref,i formed by the i-th receiving unit on the transmitting coil side:

[0042]

[0043] The real part is positive ( When the real part is negative, the receiving unit absorbs active power from the shared track; When the receiving unit injects the regenerative power from the DC side of the vehicle end into the shared track via an active full bridge, the receiving unit will inject the regenerative power from the DC side of the vehicle end into the shared track.

[0044] In this embodiment, the coordination controller calculates the regenerative power that can be injected into the braking vehicle and the power that can be absorbed by the traction vehicle based on the DC bus voltage, DC current, vehicle status and power requirements of each vehicle; then, it allocates the track-side power reference according to the primary side non-reverse flow constraint and generates the amplitude command and phase command of each receiving side active full bridge.

[0045] The coordination controller includes a vehicle state recognition unit, a sampling unit, a traction power demand calculation unit, a regenerative power calculation unit, an injection / absorption vehicle classification unit, a primary-side non-reverse flow constraint unit, a power reference allocation unit, an amplitude and phase generation unit, and an active full-bridge drive unit. Specifically: (1) The vehicle status identification unit determines whether the vehicle is in traction, heavy load, no load or braking state based on the vehicle operation command, speed change, motor power command or vehicle-end DC bus power. Determining whether a vehicle is in traction, heavy load, unloaded, or braking state based on vehicle operation commands, speed changes, motor power commands, or DC bus power at the vehicle end can be done using mature existing technologies, which will not be elaborated here.

[0046] (2) The sampling unit is used to collect the DC bus voltage, DC current and vehicle status of each OHT vehicle; (3) The traction power demand calculation unit is used to determine the absorbable power demand Preq,i of the traction vehicle in the current control cycle based on the traction power command, the DC bus voltage at the vehicle end and the DC current at the vehicle end; The determination of the aforementioned absorbable power requirement pertains to DC-side power calculation and limiting. The DC current Idc,i at the vehicle end is defined as positive when the DC bus at the vehicle end supplies power to the traction load. The absorbable power requirement Preq,i of the traction vehicle can be determined according to the following formula: , Ptr,i* represents the traction power command, Pabs,max,i represents the maximum absorbed power of the i-th vehicle-end receiving unit, which is jointly limited by the active full-bridge capacity of the receiving side, the current limit of the receiving coil, and the allowable power of the vehicle-end load, and [x]+ represents max{x,0}. When no independent traction power command is set, Ptr,i* can be taken as [Udc,iIdc,i]+.

[0047] The above calculations are conventional power measurements in this field. The improvement of this invention focuses on the coordinated reuse of regenerative energy among different vehicles.

[0048] The regenerative power calculation unit is used to determine the injectable regenerative power Pregen,i of the braking vehicle in the current control cycle based on the braking power command, the vehicle-end DC bus voltage, the vehicle-end DC current, and the allowable DC bus voltage range. The determination of the injectable regenerative power mentioned above pertains to DC-side power calculation and limiting. Following the aforementioned positive current direction, the injectable regenerative power Pregen,i of the braking vehicle can be determined according to the following formula: , Pbr,i* represents the positive value of the regenerative braking power command, Pinj,max,i represents the maximum injectable power of the i-th vehicle-end receiving unit, which is jointly limited by the active full-bridge capacity of the receiving side, the current limit of the receiving coil, and the allowable voltage range of the vehicle-end DC bus, and [x]+ represents max{x,0}. When the vehicle-end DC bus voltage exceeds the allowable range, the overvoltage / residual power protection unit performs braking power limiting or residual power absorption processing.

[0049] (4) The injection / absorption vehicle classification unit divides the OHT vehicles that are in braking state and have injectable regenerative power into an injection set, and divides the OHT vehicles that are in traction or heavy load state and have absorbable power requirements into an absorption set. (5) The primary side non-reverse injection constraint unit determines the upper limit of the allowable injection power based on the initial injection power of the injection set, the initial absorption power of the absorption set, the track loss and the safety margin, so that the primary side DC power supply or DC bus maintains a non-negative input power during coordinated operation. The initial injection power of the injection set specifically refers to the sum of the injectable regenerable power Pregen,i of the injection set determined by step (3); The initial absorbed power of the absorption set specifically refers to the sum of the absorbable power requirements Preq,i of the absorption set determined in step (3).

[0050] The upper limit of the allowable injection power is determined according to the following formula: , in, Maximum allowable injection power; The initial absorbed power of the absorbing set; For track loss; For safety margin.

[0051] P marginA non-negative power margin is reserved from the sum of the absorbable power of the absorbing set and track losses to compensate for power estimation errors, communication delays, and parameter deviations; therefore, the safety margin adopts a subtraction term. P margin When the value is zero, it corresponds to the critical non-reverse power condition where the primary side input power is not less than zero.

[0052] Therefore, the original edge non-reverse flow constraint can be uniformly expressed as:

[0053] in, The sum of the injected power Pinj,i allocated to each vehicle end; Pinj,lim is the upper limit of the allowed injected power; Pabs,raw is the initial absorbed power of the absorption set, that is, the sum of the absorbable power requirements Preq,j of each vehicle end in the absorption set; Ploss,trk is the equivalent loss of the shared track and the online pickup; Pmargin is the non-negative reserved power margin.

[0054] (6) The power reference allocation unit generates the injection power reference for the braking vehicle and the absorption power reference for the traction vehicle according to the upper limit of the allowable injection power and the absorbable power of the absorption set. The injected power reference Pinj,ref,i for braking vehicles refers to the non-negative active power command that the i-th braking vehicle is allowed to inject into the shared track in the current control cycle after the primary side non-reverse flow constraint and power allocation; this command is not greater than the regenerative power that the vehicle can currently inject.

[0055] The power absorption reference Pabs,ref,j of the traction vehicle refers to the non-negative active power command required by the j-th traction or heavy-load vehicle to absorb from the shared track in the current control cycle, based on the power demand and allowable absorption capacity of the j-th traction or heavy-load vehicle; this command is not greater than the current power absorption demand of the vehicle.

[0056] The specific operation steps of the power reference allocation unit in generating the injected power reference and absorbed power reference include: First, sum the injectable regenerative power of each braking vehicle in the injection set and the absorbable power demand of each traction vehicle in the absorption set to obtain the initial injection power Pinj,raw and the initial absorption power Pabs,raw.

[0057]

[0058] in, For the injection collection, For absorbing sets; The injectable regenerative power is injected into the i-th braking vehicle in the set; To absorb the absorbable power demand of the j-th traction vehicle in the set.

[0059] Second, the upper limit of the allowable injection power is calculated based on the initial absorbed power, track loss and safety margin, and the smaller value between the initial injection power and the upper limit of the allowable injection power is determined as the reference for the total injection power. , This is the reference for the total injected power.

[0060] The weight α is determined based on the proportion of injectable regenerative power to initial injected power for each braking vehicle, or based on vehicle priority and DC bus voltage deviation. i Allocate total injected power reference; The power absorption reference is determined according to the power requirements of each traction vehicle.

[0061] Where, α i It is not less than zero, and the sum of the weights in the injection set is 1; when Pinj,raw is zero, the injection power reference of each braking vehicle is set to zero.

[0062] (7) The amplitude and phase generation unit calculates the fundamental output amplitude and phase of the active full bridge on the receiving side based on the vehicle-end power reference, the vehicle-end DC bus voltage, and the mutual inductance or coupling parameters of the receiving coil and the transmitting coil. The steps of the amplitude and phase generation unit in calculating the amplitude and phase of the fundamental wave output of the active full-bridge receiver from the vehicle-end power reference include: First, based on the operating angular frequency ω, the mutual inductance Mi between the i-th receiving coil and the transmitting coil, and the transmitting coil current phasor, calculate the induced voltage phasor of the i-th receiving coil. :

[0063] Second, the absorbed power reference is denoted as positive and the injected power reference as negative, and the track-side complex power reference at the i-th vehicle end is constructed. When there is no reactive power regulation requirement, set the reactive power reference to zero:

[0064] Third, calculate the receiving coil current reference based on the induced voltage phasor and the track-side complex power reference. Then, based on the receiver-side S-compensation branch impedance Zs,i, the reference AC terminal fundamental voltage of the active full-bridge is calculated. :

[0065]

[0066] Fourth, calculate the modulation index based on the AC terminal fundamental voltage reference of the active full-bridge and the DC bus voltage at the vehicle end. and phase command And the amplitude is limited according to the allowable range of modulation index, receiving coil current and bridge arm fundamental voltage:

[0067]

[0068] The rate reference includes the injected power reference and the absorbed power reference.

[0069] For the k-th vehicle end, a uniformly defined signed trackside active power reference Ptrk,k* is defined: When the kth vehicle end belongs to the absorption set, Ptrk,k*=Pabs,ref,k; When it belongs to the injection set, Ptrk,k*=-Pinj,ref,k; In other states, Ptrk,k*=0.

[0070] (8) The coordination controller further includes an overvoltage / residual power protection unit: When the DC bus voltage at the vehicle end exceeds a preset threshold, or when the injectable regenerative power exceeds the sum of the absorbable power of the absorption set and the track loss minus a non-negative safety margin, the overvoltage / residual power protection unit reduces the injected power reference or enables the residual absorption branch.

[0071] The technical solution of this embodiment will be explained in detail below.

[0072] like Figure 1 As shown, in one embodiment, the primary-side DC power supply / DC bus 101 supplies power to the primary-side full-bridge inverter 102, which drives the transmitting coil 104 via the primary-side LCC compensation network 103. The transmitting coil 104 is coupled to the first receiving coil 106 and the second receiving coil 112 via the first magnetic coupling channel 105 and the second magnetic coupling channel 111, respectively. The first receiving coil 106 is connected to the first receiving-side active full-bridge 108 via the first receiving-side S compensation network 107, and the DC side of the first receiving-side active full-bridge 108 is connected to the first vehicle-end DC bus / filter capacitor 109 and the first vehicle-end load 110. The second receiving coil 112 is connected to the second receiving-side active full-bridge 114 via the second receiving-side S compensation network 113, and the DC side of the second receiving-side active full-bridge 114 is connected to the second vehicle-end DC bus / filter capacitor 115 and the second vehicle-end load 116.

[0073] In some embodiments, the first vehicle-end load 110 and the second vehicle-end load 116 may include a motor drive port, a vehicle-end DC load, a braking energy port, or a combination thereof. When the corresponding vehicle is in a braking state, the vehicle-end motor drive port generates regenerative power, and the receiving-side active full-bridge adjusts its AC terminal fundamental voltage, causing the corresponding pickup to present a negative reflective impedance on the track side; when the corresponding vehicle is in a traction or heavy-load state, the receiving-side active full-bridge adjusts its AC terminal fundamental voltage, causing the corresponding pickup to present a positive reflective impedance and absorb power from the track side.

[0074] To illustrate the power relationship on the receiving side, the energy balance of the DC bus at the vehicle end of the i-th OHT vehicle-end receiving unit can be expressed as:

[0075] Where Cdc,i is the DC bus capacitor of the i-th vehicle end, Vdc,i is the DC bus voltage of the i-th vehicle end, Ptrk,i is the track-side exchange power, Pregen,i is the regenerative power generated by vehicle braking, and Pload,i is the power consumed by traction or vehicle end load; the left side of the equation represents the rate of change of energy stored in the DC bus capacitor of the i-th vehicle end. Here, the flow of power from the track to the OHT vehicle is defined as positive.

[0076] The track-side exchange power Ptrk,i refers to the average fundamental active power exchanged between the i-th receiving unit and the shared track through the magnetic coupling channel, and its calculation formula is:

[0077] Under the fundamental frequency approximation, the AC terminal voltage of the active full-bridge receiver is... It can be represented as:

[0078] Where km is the fundamental frequency coefficient of the active full-bridge circuit, mi is the modulation index, Vdc,i is the DC bus voltage at the vehicle end, e^(jφi) is the complex exponential factor representing the phase φi, j is the imaginary unit, and φi is the phase of the fundamental frequency voltage at the AC end of the active full-bridge circuit on the receiving side. By changing mi and φi, the sign of the real part of the equivalent impedance on the receiving side can be changed.

[0079] The induced voltage obtained by the i-th receiving coil from the transmitting coil It can be represented as:

[0080] Where ω is the angular frequency, and Mi is the mutual inductance between the i-th receiving coil and the transmitting coil. This is the current phasor on the transmitting coil side.

[0081] To facilitate power coordination among multiple vehicles in the same area, the injected power is defined. and absorbed power for:

[0082] When Ptrk,i is negative, the i-th OHT vehicle-end receiver unit injects power into the track; when Ptrk,i is positive, the i-th OHT vehicle-end receiver unit absorbs power from the track.

[0083] Where Pinj,i represents the non-negative active power injected into the track by the i-th OHT vehicle-end receiving unit, and Pabs,i represents the non-negative active power absorbed from the track by the i-th OHT vehicle-end receiving unit.

[0084] max(-Ptrk,i,0) means: when Ptrk,i is less than zero, take its opposite as the injection power Pinj,i; when Ptrk,i is greater than or equal to zero, the injection power Pinj,i is zero.

[0085] max(Ptrk,i,0) means: when Ptrk,i is greater than zero, Ptrk,i is taken as the absorbed power Pabs,i; when Ptrk,i is less than or equal to zero, the absorbed power Pabs,i is zero.

[0086] like Figure 2 As shown, the coordination controller includes a vehicle status identification unit 301, a sampling unit 302, a traction power demand calculation unit 303, a regenerative power calculation unit 304, an injection / absorption vehicle classification unit 305, a primary-side non-reverse flow constraint unit 306, a power reference allocation unit 307, an amplitude and phase generation unit 308, an active full-bridge drive unit 309, and an overvoltage / residual power protection unit 310. The sampling unit 302 collects the vehicle-end DC bus voltage Udc,i, the vehicle-end DC current Idc,i, and the vehicle status i, and provides data to the vehicle status identification unit 301, the regenerative power calculation unit 304, or other units.

[0087] The vehicle status identification unit 301 determines the vehicle status based on the vehicle operation command, speed change, motor power command, or vehicle-end DC bus power. The traction power demand calculation unit 303 calculates the traction power demand Preq,i; the regenerative power calculation unit 304 calculates the injectable regenerative power Pregen,i. The injection / absorption vehicle classification unit 305 classifies vehicles into an injection set Iinj and an absorption set Iabs based on their status, and generates initial injection power Pinj,raw and initial absorption power Pabs,raw.

[0088] The initial injected power Pinj,raw is equal to the sum of the regenerative power that can currently be injected by each braking vehicle in the injection set, and the initial absorbed power Pabs,raw is equal to the sum of the power requirements that can currently be absorbed by each traction or heavy-duty vehicle in the absorption set, that is:

[0089]

[0090] The primary-side non-reverse injection constraint unit 306 determines the upper limit of the allowable injection power based on the initial absorbed power, track loss, and safety margin, and determines the smaller value between the initial injection power and the upper limit of the allowable injection power as the reference for the total injection power. The upper limit of the allowable injection power is:

[0091] To ensure that the primary-side input power remains non-negative even with power estimation errors and communication delays, Pmargin is defined as a non-negative reserved power margin, which is deducted from the sum of Pabs,raw and Ploss,trk. Thus, the upper limit of injected power is allowed to use the same parameter definition as the primary-side non-reverse injection constraint.

[0092] The primary edge non-reverse flow constraint can be expressed as:

[0093] in, The sum of the injection power Pinj,i is allocated to each vehicle end in the injection set; Pinj,lim is the upper limit of the allowed injection power; Pabs,raw is the initial absorption power of the absorption set, that is, the sum of the absorbable power requirements Preq,j of each vehicle end in the absorption set; Ploss,trk is the equivalent loss of the shared track and the online pickup; Pmargin is the non-negative reserved power margin.

[0094] This constraint is used to prevent excessive power injection into the braking vehicle, which would force the primary DC power supply or DC bus into a reverse power feeding state.

[0095] When the injectable regenerative power of the injection set exceeds the absorbable power, the residual power can be expressed as:

[0096] Wherein, Pres is the portion of the initial injectable regenerative power Pinj,raw that exceeds the upper limit of the allowable injected power Pinj,lim; when Pres is greater than zero, the overvoltage / residual power protection unit absorbs the residual power by reducing the braking power command, limiting the injected power reference, or enabling the residual absorption branch.

[0097] When residual power or overvoltage occurs on the vehicle-end DC bus, the overvoltage / residual power protection unit 310 issues a power limiting command or activates the residual absorption branch.

[0098] The power reference allocation unit 307 generates the allocated injection power reference Pinj,ref,i and absorption power reference Pabs,ref,j based on the injectable power Pinj,lim after the primary edge non-reverse injection constraint and the absorption capacity of the absorption set Iabs.

[0099] The amplitude and phase generation unit 308 generates the active full-bridge output amplitude Ak and phase φk based on the signed track-side power reference Ptrk,k* of the k-th vehicle end, the DC bus voltage of the vehicle end, and the coupling parameters; wherein, Ptrk,k* takes Pabs,ref,k in absorption mode and -Pinj,ref,k in injection mode.

[0100] The active full-bridge drive unit 309 outputs active full-bridge drive signals Si,1 to Si,4 from the receiving side accordingly.

[0101] The four power switching devices in the active full-bridge on the receiving side are driven by the active full-bridge drive signals Si,1 to Si,4 on the receiving side; the power switching devices are MOSFETs, IGBTs or other controllable semiconductor switching devices.

[0102] Compared with the prior art, the present invention has at least the following beneficial effects: First, the braking vehicle and the traction vehicle use the same type of bidirectional active pickup hardware. The injection mode and absorption mode are distinguished by the active full-bridge modulation strategy on the receiving side, which helps to reduce the differences in vehicle hardware.

[0103] Second, the primary-side full-bridge inverter maintains unidirectional high-frequency excitation and does not need to be modified into a bidirectional feedback converter, which is convenient to implement in existing OHT wireless power supply areas.

[0104] Third, by using the primary-side non-reverse flow constraint, the regenerative braking power is preferentially limited to be absorbed by traction or heavy-duty vehicles within the same area. The unabsorbed portion is then processed through power limiting or residual absorption branches, which helps to improve the controllability of the system's operating boundary.

[0105] Fourth, the combination of overvoltage protection on the DC bus at the vehicle end and power distribution on the track side can reduce the risk of overvoltage at the vehicle end during the braking energy reuse process.

[0106] Example 2 This embodiment discloses a method for controlling the reuse of regenerative energy in an OHT wireless power supply system.

[0107] A method for controlling the reuse of regenerative energy in an OHT wireless power supply system, applied to the OHT wireless power supply system described in Example 1, the method comprising: S401, obtain the vehicle status within the same area; S402, determine whether the vehicle is in a traction, heavy load, unloaded or braking state; S403, calculate the regenerative power that can be injected into the braking vehicle; S404, calculate the power that the traction vehicle can absorb; S405, determine whether the original edge non-reverse flow constraint is satisfied; S406, when the primary side non-reverse flow constraint is satisfied, allocate the orbital side injected power reference and absorbed power reference; S407, reduce the injection power or enable the residual absorption branch when the primary side non-reverse flow constraint is not met or there is an overvoltage risk. S408 calculates the amplitude and phase of the active full-bridge receiver based on the power reference. S409, controls the braking vehicle to enter negative reflective impedance mode; S410 controls the traction vehicle to enter positive reflective impedance mode; S411, determine if the DC bus at the vehicle end is over-voltage; S412, enters the next control cycle if there is no overvoltage.

[0108] The primary edge non-reverse injection constraint is: the total injection power of the injection set in the same region is not greater than the sum of the total absorption power of the absorption set and the track loss minus the non-negative safety margin, and the difference is not less than zero.

[0109] When the injectable regenerative power of the braking vehicle is greater than the absorbable power of the traction vehicle, the absorbable portion is preferentially allocated to the traction vehicle, and the remaining portion is reduced in power or allocated to the residual absorption branch through a power limiting command.

[0110] The negative reflection impedance mode and the positive reflection impedance mode are implemented by the same active full-bridge hardware on the receiving side. The mode switching is determined by the amplitude command and phase command of the active full-bridge on the receiving side, without changing the unidirectional high-frequency excitation mode of the primary full-bridge inverter.

[0111] In the above embodiment, the primary-side full-bridge inverter 102 always maintains unidirectional high-frequency excitation according to the primary-side power supply requirements. The regenerative energy of the braking vehicle is not directly fed back to the primary-side DC power supply, but is absorbed by traction or heavy-load vehicles in the same area through a shared track under the primary-side non-reverse feeding constraint; when the absorption capacity in the same area is insufficient, it is handled through power limiting or residual absorption branches, thereby maintaining the system operating boundary.

[0112] Those skilled in the art will understand that the modules or steps of the present invention described above can be implemented using general-purpose computer devices. Optionally, they can be implemented using computer-executable program code, thereby allowing them to be stored in a storage device for execution by a computer device, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. The present invention is not limited to any particular combination of hardware and software.

[0113] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. An OHT wireless power supply system, characterized in that, The system includes a primary-side transmitter and at least two OHT (On-Board Transmitter) vehicle-side receiver units. The primary-side transmitter includes a primary-side full-bridge inverter and a transmitting coil. The OHT vehicle-side receiver unit includes a receiving coil, a receiving-side active full-bridge inverter, and a vehicle-side DC bus. The primary-side full-bridge inverter is connected to the transmitting coil, and the transmitting coil is coupled to the receiving coil. The AC side of the receiving-side active full-bridge inverter is connected to the receiving coil, and the DC side of the receiving-side active full-bridge inverter is connected to the vehicle-side DC bus. The receiving-side active full-bridge is a bidirectional full-bridge converter.

2. The OHT wireless power supply system as described in claim 1, characterized in that, The primary-side transmitter also includes a primary-side power supply component and a primary-side LCC compensation network. The primary-side power supply component is a primary-side DC power supply or a DC bus. The primary-side power supply component is connected to the primary-side full-bridge inverter, and the primary-side full-bridge inverter is connected to the transmitting coil through the primary-side LCC compensation network.

3. The OHT wireless power supply system as described in claim 1, characterized in that, Each of the OHT vehicle-side receiving units is installed on an OHT vehicle, and multiple OHT vehicles are installed on a shared track; the OHT vehicle-side receiving unit also includes a receiving-side S-compensation network and a vehicle-side load port; the AC side of the receiving-side active full-bridge is connected to the receiving coil through the receiving-side S-compensation network, and the vehicle-side load port is connected to the vehicle-side DC bus; the vehicle-side load port includes a motor drive port, a vehicle-side DC load, and a braking energy port.

4. The OHT wireless power supply system as described in claim 3, characterized in that, It also includes a coordination controller, which is used to adjust the phase relationship between the AC terminal fundamental voltage of the receiving active full bridge and the induced voltage of the receiving coil, thereby switching the positive reflection impedance mode and the negative reflection impedance mode of the OHT vehicle-end receiving unit.

5. The OHT wireless power supply system as described in claim 4, characterized in that, The coordination controller is used to control the corresponding receiving side active full bridge to enter negative reflective impedance mode when the OHT vehicle is in braking state, so that the OHT vehicle injects regenerative power into the shared track; when the OHT vehicle is in traction or heavy load state, it controls the corresponding receiving side active full bridge to enter positive reflective impedance mode, so that the OHT vehicle absorbs power from the shared track.

6. The OHT wireless power supply system as described in claim 4, characterized in that, The coordination controller is also used to determine the primary-side non-reverse injection constraint and calculate the upper limit of the allowed injection power: OHT vehicles that are in braking condition and have injectable regenerative power are classified into the injection set, and OHT vehicles that are in traction or heavy load condition and have absorbable power requirements are classified into the absorption set. The sum of the absorbable power of the absorbing set and the track loss is calculated, and the upper limit of the allowable injected power is determined after deducting the non-negative safety margin, and the upper limit of the allowable injected power is not less than zero. After obtaining the maximum allowed injected power, the coordination controller is further configured to: Based on the upper limit of the allowed injected power and the absorbable power of the absorption set, the injected power reference for the braking vehicle and the absorbed power reference for the traction vehicle are generated respectively. When the DC bus voltage at the vehicle end exceeds a preset threshold, or when the injectable regenerative power exceeds the upper limit of the allowable injectable power, the control will reduce the injectable power reference or enable the residual absorption branch.

7. The OHT wireless power supply system as described in claim 1, characterized in that, The coordination controller is also used to calculate the fundamental output amplitude and phase of the active full-bridge receiver based on the vehicle-end power reference, the vehicle-end DC bus voltage, and the mutual inductance or coupling parameters of the receiving coil and the transmitting coil.

8. A method for controlling the reuse of regenerative energy in an OHT wireless power supply system, characterized in that, Includes the following steps: Define the area, identify the vehicles within the same area, and determine whether the vehicles within the same area are in a tractor-trailer, heavily loaded, unloaded, or braking state. Calculate the injectable regenerative power of the vehicle under braking conditions; Calculate the absorbable power of the vehicle under traction conditions; Based on the injectable regenerative power of the vehicle in braking state and the absorbable power of the vehicle in traction state, determine whether the primary-side non-reverse flow constraint is satisfied. When the primary side non-reverse flow constraint is satisfied, the orbital side injected power reference and absorbed power reference are allocated; The output amplitude and phase of the active full-bridge receiver are calculated based on the power reference. Control the braking vehicle to enter negative reflective impedance mode and control the traction vehicle to enter positive reflective impedance mode; Determine if the DC bus at the vehicle end is overvoltage, and if so, reduce the injected power reference or enable the residual absorption branch.

9. The regenerative energy reuse control method for the OHT wireless power supply system as described in claim 8, characterized in that, The primary edge non-reverse flow constraint is: The total injection power of the injection set within the same region is not greater than the sum of the total absorption power of the absorption set and the track loss minus the non-negative safety margin, and the difference is not less than zero.

10. The regenerative energy reuse control method for the OHT wireless power supply system as described in claim 8, characterized in that, When the regenerative power that can be injected into the braking vehicle is greater than the power that can be absorbed by the traction vehicle, the absorbable portion is preferentially allocated to the traction vehicle, and the remaining portion is reduced in power injection or allocated to the residual absorption branch through power limiting command.

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