High-power PFC (Power Factor Correction) switching power supply circuit for sky rail system

Abstract

The invention relates to a high-power PFC (Power Factor Correction) switching power supply circuit for a sky rail system, which comprises a commercial power EMI (Electro-Magnetic Interference) filter circuit, a rectification and PFC power factor correction module and an inversion LLC (Logical Link Control) resonant rectification circuit which are connected in sequence, the commercial power EMI filter circuit comprises a surge protection circuit and an EMI filter circuit, one side of the surge protection circuit is connected with commercial power, and the other side of the surge protection circuit is connected with an EMI filter circuit. The rectification and PFC power factor correction module comprises a rectification module, a PFC circuit and a sampling module, the rectification module is connected with the input end of the PFC circuit, the sampling module is arranged at the output end of the PFC circuit, the sampling module is connected with the PFC circuit, the PFC circuit outputs high-voltage direct current, and the PFC circuit outputs high-voltage direct current. And the high-voltage direct current outputs low-voltage direct current through the inversion LLC resonance rectification circuit. According to the invention, efficient and stable electric energy supply is provided for the sky rail system through the commercial power.

Description

A high-power PFC switching power supply circuit for a skyrail system Technical Field

[0001] This invention relates to the field of medical ceiling track power supply technology, specifically to a high-power PFC switching power supply circuit for ceiling track systems. Background Technology

[0002] The overhead track system is used in rehabilitation, intensive care unit (ICU), geriatrics, orthopedics and other scenarios. It is precisely adapted to patients in the postoperative recovery period, patients with lower limb paralysis / weakness, elderly and frail patients, critically ill bedridden patients, and patients with fracture fixation. The load-bearing capacity can reach 150-300kg. It can be equipped with a variety of accessories such as full-body slings, sitting suspension devices, and prone supports to adapt to different body position requirements and can also adapt to the displacement of medical devices.

[0003] In existing technologies, most ceiling-mounted systems are battery-powered, using built-in or external battery packs for power. As high-power rehabilitation aids, these systems consume a lot of power during motor drive and patient transport, resulting in poor battery life. When the battery is depleted, it needs to be removed for charging, failing to meet continuous use requirements. Installing the ceiling-mounted system requires constraints on the overall weight and size of the equipment to achieve movement along the track, limiting battery capacity and making it difficult to use large-capacity battery packs. Furthermore, the limited battery life necessitates periodic disassembly and battery replacement, a cumbersome process that increases maintenance costs. The core function of the ceiling-mounted system is to precisely control the transport speed and position using a motor to adapt to the patient's gait rehabilitation or safe transfer needs. However, battery power is prone to voltage fluctuations under sudden load scenarios such as motor start-up and instantaneous acceleration while carrying the patient, leading to unstable motor speed, deviations in transport accuracy, and potential safety hazards.

[0004] Therefore, a new power supply method is urgently needed to replace battery power and meet the power needs of the skyrail system. Summary of the Invention

[0005] To address the issues associated with battery power supply, a high-power PFC switching power supply circuit for the skyrail system is provided. This circuit incorporates a mains EMI filter circuit to effectively suppress high-frequency interference from the mains side, utilizes high-power PFC technology to reduce grid harmonic pollution, and employs an inverter LLC resonant rectifier circuit to minimize voltage fluctuations. This enables the skyrail system to be powered by mains electricity, thus meeting the system's power requirements.

[0006] To achieve the above objectives, this invention proposes a high-power PFC switching power supply circuit for a skyrail system, including a power supply and a mains EMI filter circuit, a rectification and PFC power factor correction module, and an inverter LLC resonant rectifier circuit connected in sequence. The mains EMI filter circuit includes a surge protection circuit and an EMI filter circuit. One end of the surge protection circuit is connected to the mains power, and the other end is connected to the rectification and PFC power factor correction module via the EMI filter circuit. The rectification and PFC power factor correction module includes a rectification module, a PFC circuit, and a sampling module. The rectification module is connected to the input terminal of the PFC circuit, and the output terminal of the PFC circuit is equipped with a sampling module. The sampling module is connected to the PFC circuit, and the PFC circuit outputs high-voltage DC power. The high-voltage DC power is output as low-voltage DC power through the inverter LLC resonant rectifier circuit.

[0007] Furthermore, the surge protection circuit includes a fuse and a surge protection unit. The fuse is connected in series with the live wire, and a surge protection unit is installed between the live wire and the neutral wire. The surge protection unit includes a parallel varistor D1, a gas discharge tube GDT1, and a series NTC thermistor connected in sequence. The EMI filtering circuit includes an RC buffer unit, a first-stage LC filter unit, and a second-stage LC filter unit. The RC buffer unit includes a capacitor C3 and resistors R1, R3, and R4 connected in parallel with capacitor C3. 4 are connected in series and connected to the first-stage LC filter unit. The first-stage LC filter unit includes an inductor L1 and a capacitor C4, a capacitor C1 and a capacitor C6 arranged in sequence. The capacitors C1 and C6 are connected in series and in parallel with the capacitor C4. The other ends of the capacitors C1 and C6 are connected to the second-stage LC filter unit. The second-stage LC filter unit includes an inductor L2, a capacitor C5, a capacitor C2 and a capacitor C7 arranged in sequence. The other end of the inductor L2 is connected to the capacitors C2 and C7 via the capacitor C5. The capacitors C2 and C7 are connected in series. The EMI filter circuit outputs AC power.

[0008] In the surge protection circuit, the varistor quickly clamps surge signals such as lightning strikes and power grid overvoltages, the gas discharge tube assists in discharging amplified current, and the NTC thermistor suppresses the start-up surge current. It can withstand common-mode surges and differential-mode surges, preventing surge impacts from damaging subsequent circuits and ensuring the continuous operation of the ceiling rail system during thunderstorms and power grid fluctuations.

[0009] The EMI filtering circuit employs multi-stage filtering technology. The RC buffer unit absorbs high-frequency noise from the switching transistors, and the first and second stage LC filter units, through the synergistic effect of inductors and capacitors, improve the ability to suppress differential-mode and common-mode interference. This avoids interference with equipment such as ward ECG monitors and ventilators, while ensuring the signal acquisition accuracy of the ceiling track system's own sensors.

[0010] Compared to single-capacitor filtering, EMI filter circuits can improve the voltage rating of the filter capacitor (to meet the rectification requirements of 220V AC mains power) while reducing the fluctuation in filtering effect caused by capacitor value deviation, ensuring the purity of the AC output power of the EMI filter circuit.

[0011] Furthermore, a discharge resistor R2 is provided between the surge protection circuit and the EMI filter circuit. The discharge resistor R2 and capacitor C3 are connected in parallel to form a RC parallel network. The discharge resistor R2 added between the surge protection circuit and the EMI filter circuit, together with capacitor C3, forms a RC parallel network, which can quickly discharge the charge stored on C3 after the power is turned off, thereby improving operational safety.

[0012] Furthermore, the rectifier module includes a rectifier bridge. The output terminal of the rectifier bridge is connected to an auxiliary power supply circuit and a PFC circuit via a filter capacitor C17. The PFC circuit includes a controller and a boost circuit. The boost circuit includes inductors L6 and L8, MOSFETs Q9 and Q14, and freewheeling diodes D5 and D6. The boost circuit has an interleaved symmetrical structure. Inductors L6 and L8 are connected to the drains of MOSFETs Q9 and Q14 respectively. The gates of MOSFETs Q9 and Q14 are connected to the controller. The anodes of freewheeling diodes D5 and D6 are connected to the connection points between the drains of MOSFETs Q9 and Q14 and inductors L6 and L8. The cathodes of freewheeling diodes D5 and D6 are connected to the inverter LLC resonant rectifier circuit.

[0013] A rectifier bridge 204, in conjunction with a filter capacitor C17, efficiently converts EMI-filtered AC power into DC power. The PFC circuit employs an interleaved symmetrical structure to reduce harmonic interference from the mains power supply and lower the current stress on individual components, enabling a miniaturized PFC module design that meets the compact installation requirements of ceiling rail equipment. The controller precisely controls the switching of MOSFETs Q9 / Q14 to ensure a stable high-voltage DC output (400V) for the PFC circuit, providing optimal input for the subsequent LLC resonant circuit. This ensures the LLC topology always operates in a zero-voltage turn-on (ZVS) state, further improving the overall power system efficiency and stability.

[0014] Furthermore, the sampling module includes current sampling resistors R10 and R13, and voltage sampling divider resistors R11 and R14; the sources of MOSFETs Q9 and Q14 are respectively connected to current sampling resistors R10 and R13, which are connected to the controller; the voltage sampling divider resistors R11 and R14 are connected in series to the cathodes of freewheeling diodes D5 and D6, respectively, and are connected to the controller; the auxiliary power supply circuit supplies power to the controller.

[0015] Dual sampling feedback of current and voltage enables the PFC circuit to have overcurrent and overvoltage protection functions. When a fault such as a load short circuit occurs, the sampling module quickly captures the abnormal signal, and the controller immediately shuts off the MOSFET drive signal to protect the core components of the PFC circuit.

[0016] Furthermore, the inverter LLC resonant rectifier circuit includes a half-bridge drive unit, an LLC resonant circuit, an LLC resonant controller, a high-frequency transformer T1, and a synchronous rectifier circuit. The half-bridge drive unit includes an upper arm switch Q1, a lower arm switch Q3, and a gate drive circuit composed of diodes D3 and D4 and pull-down resistors. Diodes D3 and D4 are connected to the gates of the upper arm switch Q1 and the lower arm switch Q3, respectively. The half-bridge drive unit is connected to the LLC resonant circuit. The LLC resonant circuit includes an LLC resonant network composed of inductor L3 and capacitor U4. Capacitor U4 is connected to a high-frequency filter capacitor. The other side of inductor L3 and capacitor U4 is connected to the primary side of the high-frequency transformer T1. A synchronous rectifier circuit is set on the secondary side of the high-frequency transformer T1. The synchronous rectifier circuit includes MOSFETs Q2 and Q4. The drains of MOSFETs Q2 and Q4 are connected to the secondary side of the high-frequency transformer T1, and the gates of MOSFETs Q2 and Q4 are connected to the output terminal of the rectifier.

[0017] In the half-bridge drive unit, the gate drive circuit composed of diodes D3 / D4 and pull-down resistors can precisely control the on / off timing of the upper arm switch Q1 and the lower arm switch Q3, avoiding short-circuit faults caused by the common-mode conduction of the two transistors. The LLC resonant circuit, in conjunction with the high-frequency transformer T1, achieves efficient conversion of high-voltage DC to high-frequency AC. The soft-switching characteristics of the LLC topology reduce switching losses, and together with the synchronous rectifier circuit, improves the efficiency of the inverter to rectification stage and reduces the heat generation of the power supply system.

[0018] Furthermore, the output terminal of the LLC resonant controller is connected to the gate drive circuit, and the LLC resonant controller is connected to the output terminal of the PFC power factor correction module; the LLC resonant controller is equipped with a resonant current acquisition module and a voltage acquisition module, and the feedback terminal of the LLC resonant controller is connected to an isolation voltage feedback circuit, the isolation voltage feedback circuit including an optocoupler element, the output terminal of the optocoupler element is connected to the LLC resonant controller, the input terminal of the optocoupler element is connected to a programmable precision reference voltage source, and the other side of the programmable precision reference voltage source is connected to the output terminal of the synchronous rectifier circuit through series voltage divider resistors R35, R38 and R43.

[0019] The LLC resonant controller is directly connected to the output of the PFC module, enabling real-time acquisition of high-voltage bus voltage information. Combined with signals from the resonant current acquisition module 6 and the voltage acquisition module 7, it dynamically adjusts the switching frequency of the half-bridge drive unit, ensuring the LLC resonant circuit always operates at its optimal resonant point and guaranteeing stable low-voltage DC output. In the isolated voltage feedback circuit, optocouplers provide electrical isolation between the high and low voltage sides, preventing interference from the 400V high-voltage side from being conducted to the low-voltage feedback loop, while also ensuring accurate transmission of the feedback signal. The programmable precision reference voltage source compares the output voltage acquired by the voltage divider resistors R35 / R38 / R43 with its own 2.5V reference, generating a precise error signal that is input to the LLC resonant controller.

[0020] The beneficial effects of this invention through the above technical solution are as follows: Addressing the high power requirements of the ceiling track system, this invention achieves efficient energy conversion through a three-stage architecture: a mains EMI filter circuit, a rectification and PFC power factor correction module, and an inverter LLC resonant rectifier circuit. The surge protection and EMI filtering design in the mains EMI filter circuit effectively suppresses lightning surges and high-frequency interference from the power grid. The stable high-voltage DC output from the rectification and PFC module provides optimal input conditions for the subsequent LLC resonant rectifier circuit, improving the overall stability of the power supply system. The low-voltage DC output from the inverter LLC resonant rectifier circuit can precisely match the voltage requirements of the ceiling track equipment's motor and control unit. Compared to traditional battery-powered DC-DC conversion, this reduces voltage fluctuations, preventing the ceiling track equipment from experiencing stuttering or speed abnormalities during motor start-up / stop or sudden load changes, ensuring patient transport safety and the smoothness of rehabilitation training. The overall circuit eliminates reliance on battery power, eliminating the need for frequent charging and battery replacement, reducing hospital equipment maintenance costs, meeting the stringent power efficiency requirements of medical scenarios, and overcoming the battery life issues of traditional battery power, ensuring the continuous and stable operation of the ceiling track equipment 24 hours a day, and meeting the continuous work needs of multi-patient rotation training, ICU emergency transfer, etc. Attached Figure Description

[0021] Figure 1 is a schematic diagram of a high-power PFC switching power supply circuit for a skyrail system according to the present invention; Figure 2 is one of the circuit diagrams of a high-power PFC switching power supply circuit for a skyrail system according to the present invention; Figure 3 is another circuit diagram of a high-power PFC switching power supply circuit for a skyrail system according to the present invention; Figure 4 is a third circuit diagram of a high-power PFC switching power supply circuit for a skyrail system according to the present invention; Figure 5 is a fourth circuit diagram of a high-power PFC switching power supply circuit for a skyrail system according to the present invention.

[0022] Reference numerals: 1 is the mains EMI filter circuit, 2 is the rectification and PFC power factor correction module, 3 is the inverter LLC resonant rectifier circuit, 101 is the surge protection unit, 102 is the RC buffer unit, 103 is the first-stage LC filter unit, 104 is the second-stage LC filter unit, 201 is the controller, 202 is the boost circuit, 203 is the sampling module, 204 is the rectifier bridge, 301 is the half-bridge drive unit, 302 is the LLC resonant circuit, 303 is the LLC resonant controller, 304 is the synchronous rectifier circuit, 305 is the rectifier, 4 is the auxiliary power supply circuit, 5 is the high-frequency filter capacitor, 6 is the resonant current acquisition module, 7 is the voltage acquisition module, 8 is the isolation voltage feedback circuit, 801 is the optocoupler, and 802 is the programmable precision reference voltage source. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and specific embodiments: Examples

[0024] As shown in Figures 1-5, a high-power PFC switching power supply circuit for a ceiling track system includes a power supply, characterized in that it further includes a mains EMI filter circuit 1, a rectification and PFC power factor correction module 2, and an inverter LLC resonant rectifier circuit 3 connected in sequence. The mains EMI filter circuit 1 includes a surge protection circuit and an EMI filter circuit. One side of the surge protection circuit is connected to the mains power, and the other end is connected to the rectification and PFC power factor correction module 2 via the EMI filter circuit. The rectification and PFC power factor correction module 2 includes a rectification module, a PFC circuit, and a sampling module. The rectification module is connected to the input terminal of the PFC circuit, and the output terminal of the PFC circuit is equipped with a sampling module. The sampling module is connected to the PFC circuit, and the PFC circuit outputs high-voltage DC power. The high-voltage DC power is output as low-voltage DC power through the inverter LLC resonant rectifier circuit 3.

[0025] The surge protection circuit includes a fuse and a surge protection unit. The fuse is connected in series with the live wire, and a surge protection unit 101 is installed between the live wire and the neutral wire. The surge protection unit 101 includes a parallel varistor D1, a gas discharge tube GDT1, and a series NTC thermistor connected in sequence. The EMI filter circuit includes an RC buffer unit 102, a first-stage LC filter unit 103, and a second-stage LC filter unit 104. The RC buffer unit 102 includes a capacitor C3 and resistors R1, R3, and R4 connected in parallel with the capacitor C3. 4 are connected in series and connected to the first-stage LC filter unit 103. The first-stage LC filter unit 103 includes an inductor L1 and a capacitor C4, a capacitor C1 and a capacitor C6 arranged in sequence. The capacitors C1 and C6 are connected in series and in parallel with the capacitor C4. The other ends of the capacitors C1 and C6 are connected to the second-stage LC filter unit 104. The second-stage LC filter unit 104 includes an inductor L2, a capacitor C5, a capacitor C2 and a capacitor C7 arranged in sequence. The other end of the inductor L2 is connected to the capacitors C2 and C7 via the capacitor C5. The capacitors C2 and C7 are connected in series. The EMI filter circuit outputs AC power.

[0026] A discharge resistor R2 is provided between the surge protection circuit and the EMI filter circuit. The discharge resistor R2 and the capacitor C3 are connected in parallel to form a resistor-capacitor parallel network.

[0027] The rectifier module includes a rectifier bridge 204. The output terminal of the rectifier bridge 204 is connected to an auxiliary power supply circuit 4 and a PFC circuit via a filter capacitor C17. The PFC circuit includes a controller 201 (U1 in Figure 2 uses a UCC29070 chip) and a boost circuit 202. The boost circuit 202 includes inductors L6 and L8, MOSFETs Q9 and Q14, and freewheeling diodes D5 and D6. The boost circuit 202 has an interleaved symmetrical structure. The inductors L6 and L8 are connected to the drains of MOSFETs Q9 and Q14 respectively. The gates of MOSFETs Q9 and Q14 are connected to controller 201 (pins are labeled GDA and GDB in Figure 2). The anodes of the freewheeling diodes D5 and D6 are connected to the connection points between the drains of MOSFETs Q9 and Q14 and inductors L6 and L8. The cathodes of the freewheeling diodes D5 and D6 are connected to the inverter LLC resonant rectifier circuit 3.

[0028] The sampling module 203 includes current sampling resistors R10 and R13, and voltage sampling divider resistors R11 and R14. The sources of MOSFETs Q9 and Q14 are connected to current sampling resistors R10 and R13 respectively. Current sampling resistors R10 and R13 are connected to controller 201 (pins labeled CSA and CSB in Figure 2). Voltage sampling divider resistors R11 and R14 are connected in series to the cathodes of freewheeling diodes D5 and D6 respectively. Voltage sampling divider resistors R11 and R14 are connected to controller 201 (pins labeled VSENSE in Figure 2). The auxiliary power supply circuit 4 supplies power to controller 201.

[0029] The inverter LLC resonant rectifier circuit 3 includes a half-bridge drive unit 301, an LLC resonant circuit 302, an LLC resonant controller 303 (UCC256404DDBR in Figure 3), a high-frequency transformer T1, and a synchronous rectifier circuit 304. The half-bridge drive unit 301 includes an upper arm switch Q1, a lower arm switch Q3, and a gate drive circuit composed of diodes D3 and D4 and pull-down resistors. Diodes D3 and D4 are connected to the gates of the upper arm switch Q1 and the lower arm switch Q3, respectively. The half-bridge drive unit 301 is connected to the LLC resonant circuit 302. 302 includes an LLC resonant network composed of inductor L3 and capacitor U4. Capacitor U4 is connected to high-frequency filter capacitors 5 (capacitors C30 and C31 in Figure 3). The other side of inductor L3 and capacitor U4 is connected to the primary side of high-frequency transformer T1. A synchronous rectifier circuit 304 is set on the secondary side of high-frequency transformer T1. The synchronous rectifier circuit 304 includes MOSFETs Q2 and Q4. The drains of MOSFETs Q2 and Q4 are connected to the secondary side of high-frequency transformer T1, and the gates of MOSFETs Q2 and Q4 are connected to the output terminal of rectifier 305 (UCC24624DR in Figure 3).

[0030] The output of the LLC resonant controller 303 (HO and LO in Figures 3 and 4) is connected to the gate drive circuit. The LLC resonant controller 303 is connected to the output of the PFC power factor correction module. The LLC resonant controller 303 is equipped with a resonant current acquisition module 6 (R38 connected to ISNS in Figure 4) and a voltage acquisition module 7 (R39 connected to FZ in Figure 4). The feedback terminal of the LLC resonant controller 303 (FB in Figure 4) is connected to an isolation voltage feedback circuit 8. The isolation voltage feedback circuit 8 includes an optocoupler 801 (EL1018T in Figure 4). The output of the optocoupler 801 is connected to the LLC resonant controller 303. The input of the optocoupler 801 is connected to a programmable precision reference voltage source 802 (TL431 in Figure 4). The other side of the programmable precision reference voltage source 802 is connected to the output of the synchronous rectifier circuit 304 via series voltage divider resistors R35, R38 and R43.

[0031] During operation, the 220V mains power is first connected to the surge protection circuit. The fuse connected in series with the live wire serves as primary overcurrent protection, quickly melting and cutting off the circuit when a short circuit or overload occurs. The surge protection unit 101 between the live wire and the neutral wire forms a triple surge protection. When encountering surge signals such as lightning strikes or grid overvoltage, the varistor D1 first quickly clamps the excessive voltage, initially dissipating the surge energy. The remaining energy is further dissipated by the gas discharge tube GDT1 to prevent high voltage from damaging subsequent components. The NTC thermistor connected in series suppresses the surge current at the moment of power-on, preventing large current surges from damaging components such as capacitors and inductors.

[0032] The surge-protected AC power enters the EMI filter circuit, first passing through the RC buffer unit 102 to absorb high-frequency spike noise generated by the mains and subsequent circuits. It then enters the first-stage LC filter unit 103, where inductor L1 impedes differential-mode interference, and capacitors C4, C1, and C6 form a common-mode / differential-mode filter network to further filter out low-frequency interference. Finally, it undergoes deep purification by the second-stage LC filter unit 104, significantly reducing the output AC ripple to meet medical-grade EMC standards.

[0033] The discharge resistor R2 between the surge protection circuit and the EMI filter circuit, together with capacitor C3, forms a parallel RC network, which can quickly discharge the residual charge stored on C3 after the power is turned off.

[0034] The clean AC power, after EMI filtering, is connected to the rectifier bridge 204 of the rectifier module. The rectifier bridge 204 converts the sinusoidal AC power into pulsating DC power through the unidirectional conductivity of four diodes. Then, the pulsating component is filtered out by the filter capacitor C17 to output a stable DC power.

[0035] After the controller 201 starts, it outputs two PWM drive signals with a 180° phase difference, which control the on / off state of MOSFETs Q9 and Q14 in the boost circuit 202, respectively. When MOSFET Q9 is on, inductor L6 stores energy; when Q9 is off, L6 releases energy, which is output through freewheeling diode D5. Similarly, MOSFET Q14, inductor L8, and freewheeling diode D6 form another boost branch, and the two branches work alternately. This staggered symmetrical structure can significantly cancel the input current ripple, improve current continuity, and reduce the current stress on individual components. The controller 201 collects the current signals of the sources of Q9 and Q14 in real time through the current sampling resistors R10 and R13 of the sampling module 203, ensuring that the input current waveform follows the mains voltage waveform, significantly reducing grid harmonic pollution and improving energy utilization efficiency. The controller 201 dynamically adjusts the duty cycle of the PWM drive signal according to the feedback signal, enabling the PFC circuit to stably output 400V high-voltage DC power. The sampling module 203 monitors the current and voltage signals in real time. When abnormalities such as overcurrent or overvoltage occur, the controller 201 immediately shuts off the drive signals of MOSFETs Q9 and Q14, stops the PFC circuit from working, protects the core components from damage, and feeds back the fault signal to the main controller of the overhead rail system.

[0036] After the LLC resonant controller 303 starts up, it first obtains the initial operating state of the LLC resonant circuit 302 through the resonant current acquisition module 6 and the voltage acquisition module 7, and then outputs a PWM drive signal to the gate drive circuit of the half-bridge drive unit 301. Diodes D3 and D4 in the gate drive circuit provide freewheeling protection for the gates of the upper arm switch Q1 and the lower arm switch Q3, respectively, and pull-down resistors ensure that the MOSFETs are reliably turned off when there is no drive signal. Under the drive of the LLC resonant controller 303, Q1 and Q3 alternately conduct (avoiding common-mode conduction), converting the 400V high-voltage DC power into high-frequency square wave AC power, which is then input to the LLC resonant circuit 302. In the LLC resonant circuit 302, the inductor L3 and capacitor U4 form a resonant network, which resonates under high-frequency square wave excitation, making the impedance of the resonant network purely resistive, realizing zero-voltage turn-on (ZVS) and zero-current turn-off (ZCS) of the switching transistor, and significantly reducing switching losses. At the same time, the resonant network efficiently transmits high-frequency AC power to the primary side of the high-frequency transformer T1, while the high-frequency filter capacitor 5 filters out high-frequency noise during the resonance process, ensuring stable energy transmission.

[0037] The high-frequency low-voltage AC power output from the secondary side of the high-frequency transformer T1 is connected to the synchronous rectifier circuit 304. The rectifier 305 outputs a synchronous drive signal to control the switching on and off of MOSFETs Q2 and Q4. The switching timing of Q2 and Q4 is precisely matched with the phase of the secondary AC power, and outputs 48V DC power to supply the ceiling track system.

[0038] The low-voltage DC (48V) output from the synchronous rectifier circuit 304 is precisely divided by a series voltage divider resistors R35, R38, and R43, and the divided voltage signal is input to the programmable precision reference voltage source 802 (TL431). The programmable precision reference voltage source 802 compares the sampled divided voltage signal with its internal 2.5V reference voltage to generate an error current signal, which controls the conduction level of the optocoupler 801. The optocoupler 801 achieves high- and low-voltage side isolation through photoelectric conversion and transmits the error signal to the feedback terminal of the LLC resonant controller 303. Based on the feedback error signal, the LLC resonant controller 303 dynamically adjusts the frequency of the PWM drive signal output to the half-bridge drive unit 301, changing the resonant state of the LLC resonant circuit 302. When the load of the sky track system increases, causing the output voltage to drop, the LLC resonant controller 303 reduces the drive frequency and increases the gain of the LLC resonant network, causing the output voltage to recover. When the load decreases and the voltage rises, the LLC resonant controller 303 increases the drive frequency and decreases the gain, causing the voltage to drop back down. Ultimately, the output voltage fluctuation rate is controlled within ±2%, ensuring that the ceiling track motor can still operate smoothly under dynamic loads such as start-up, shutdown, and sudden load changes.

[0039] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Therefore, all equivalent changes or modifications made to the structure, features and principles described in the claims of the present invention should be included within the scope of the present invention.

Claims

1. A high-power PFC switching power supply circuit for a skyrail system, comprising a power supply, characterized in that, It also includes a mains EMI filter circuit (1), a rectifier and PFC power factor correction module (2) and an inverter LLC resonant rectifier circuit (3) connected in sequence. The mains EMI filter circuit (1) includes a surge protection circuit and an EMI filter circuit. One side of the surge protection circuit is connected to the mains power, and the other end is connected to the rectifier and PFC power factor correction module (2) through the EMI filter circuit. The rectifier and PFC power factor correction module (2) includes a rectifier module, a PFC circuit and a sampling module. The rectifier module is connected to the input end of the PFC circuit, and the output end of the PFC circuit is equipped with a sampling module. The sampling module is connected to the PFC circuit. The PFC circuit outputs high voltage DC power, and the high voltage DC power is output as low voltage DC power through the inverter LLC resonant rectifier circuit (3).

2. The high-power PFC switching power supply circuit for a skyrail system according to claim 1, characterized in that, The surge protection circuit includes a fuse and a surge protection unit. The fuse is connected in series with the live wire, and a surge protection unit (101) is provided between the live wire and the neutral wire. The surge protection unit (101) includes a parallel varistor D1, a gas discharge tube GDT1, and a series NTC thermistor connected in sequence. The EMI filter circuit includes an RC buffer unit (102), a first-stage LC filter unit (103), and a second-stage LC filter unit (104). The RC buffer unit (102) includes a capacitor C3 and resistors R1, R3, and R4 connected in parallel with the capacitor C3. Resistor R4 is connected in series and connected to the first-stage LC filter unit (103). The first-stage LC filter unit (103) includes an inductor L1 and a capacitor C4, a capacitor C1 and a capacitor C6 arranged in sequence. The capacitors C1 and C6 are connected in series and in parallel with the capacitor C4. The other end of the capacitors C1 and C6 is connected to the second-stage LC filter unit (104). The second-stage LC filter unit (104) includes an inductor L2, a capacitor C5, a capacitor C2 and a capacitor C7 arranged in sequence. The other end of the inductor L2 is connected to the capacitors C2 and C7 via the capacitor C5. The capacitors C2 and C7 are connected in series. The EMI filter circuit outputs AC power.

3. A high-power PFC switching power supply circuit for a skyrail system according to claim 2, characterized in that, A discharge resistor R2 is provided between the surge protection circuit and the EMI filter circuit. The discharge resistor R2 and the capacitor C3 are connected in parallel to form a resistor-capacitor parallel network.

4. A high-power PFC switching power supply circuit for a skyrail system according to claim 1, characterized in that, The rectifier module includes a rectifier bridge (204). The output terminal of the rectifier bridge (204) is connected to an auxiliary power supply circuit (4) and a PFC circuit via a filter capacitor C17. The PFC circuit includes a controller (201) and a boost circuit (202). The boost circuit (202) includes inductors L6 and L8, MOSFETs Q9 and Q14, and freewheeling diodes D5 and D6. The boost circuit (202) has an interleaved symmetrical structure. Inductors L6 and L8 are connected to the drains of MOSFETs Q9 and Q14 respectively. The gates of MOSFETs Q9 and Q14 are connected to the controller (201). The anodes of freewheeling diodes D5 and D6 are connected to the connection points between the drains of MOSFETs Q9 and Q14 and inductors L6 and L8 respectively. The cathodes of freewheeling diodes D5 and D6 are connected to the inverter LLC resonant rectifier circuit (3).

5. A high-power PFC switching power supply circuit for a skyrail system according to claim 4, characterized in that, The sampling module (203) includes current sampling resistors R10 and R13, voltage sampling divider resistors R11 and R14; the sources of MOS transistors Q9 and Q14 are connected to current sampling resistors R10 and R13 respectively, and current sampling resistors R10 and R13 are connected to the controller (201) respectively; the voltage sampling divider resistors R11 and R14 are connected in series to the cathodes of freewheeling diodes D5 and D6 respectively, and the voltage sampling divider resistors R11 and R14 are connected to the controller (201); the auxiliary power supply circuit (4) supplies power to the controller (201).

6. A high-power PFC switching power supply circuit for a skyrail system according to claim 1, characterized in that, The inverter LLC resonant rectifier circuit (3) includes a half-bridge drive unit (301), an LLC resonant circuit (302), an LLC resonant controller (303), a high-frequency transformer T1, and a synchronous rectifier circuit (304); the half-bridge drive unit (301) includes an upper arm switch Q1, a lower arm switch Q3, and a gate drive circuit composed of diodes D3 and D4 and pull-down resistors. Diodes D3 and D4 are connected to the gates of the upper arm switch Q1 and the lower arm switch Q3, respectively. The half-bridge drive unit (301) is connected to the LLC resonant circuit (302). The LLC resonant circuit (302) includes an LLC resonant network composed of an inductor L3 and a capacitor U4. The capacitor U4 is connected to a high-frequency filter capacitor (5). The other side of the inductor L3 and the capacitor U4 is connected to the primary side of the high-frequency transformer T1. A synchronous rectifier circuit (304) is set on the secondary side of the high-frequency transformer T1. The synchronous rectifier circuit (304) includes a MOSFET Q2 and a MOSFET Q4. The drains of the MOSFETs Q2 and Q4 are connected to the secondary side of the high-frequency transformer T1, and the gates of the MOSFETs Q2 and Q4 are connected to the output terminal of the rectifier (305).

7. A high-power PFC switching power supply circuit for a skyrail system according to claim 6, characterized in that, The output terminal of the LLC resonant controller (303) is connected to the gate drive circuit, and the LLC resonant controller (303) is connected to the output terminal of the PFC power factor correction module. The LLC resonant controller (303) is provided with a resonant current acquisition module (6) and a voltage acquisition module (7). The feedback terminal of the LLC resonant controller (303) is connected to an isolation voltage feedback circuit (8). The isolation voltage feedback circuit (8) includes an optocoupler element (801). The output terminal of the optocoupler element (801) is connected to the LLC resonant controller (303). The input terminal of the optocoupler element (801) is connected to a programmable precision reference voltage source (802). The other side of the programmable precision reference voltage source (802) is connected to the output terminal of the synchronous rectifier circuit (304) through series voltage divider resistors R35, R38 and R43.

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