Discrete current type control method and device for totem-pole bridgeless PFC

Abstract

The invention discloses a discrete current type control method and device for totem-pole bridgeless PFC, and is suitable for the field of electric energy conversion and control and the field of switching converter control and modulation. According to the device, the unity power factor of the input side of the converter and the fast transient response control target can be achieved; according to the control method provided by the invention, a proportional-integral controller, an error amplifier and a compensation network thereof are not needed in a voltage control loop, the controller is simple in design and low in software cost, and a fast transient response control target can be realized; besides, according to the control method provided by the invention, the input current reference of the current control loop is obtained by an input current reference calculation module and is not interfered by double power frequency ripples of the output voltage, and decoupling of the voltage loop and the current loop is realized, so that a low input current distortion control target can be realized, and the control method has certain academic and engineering application values.

Description

Technical Field

[0001] This invention belongs to the fields of power conversion and control, power electronic switching converters, and PWM rectifier control and modulation, and in particular relates to a discrete current-type control method and device for totem pole bridgeless PFC. Background Technology

[0002] With the rapid development of power electronics technology, various electronic devices are placing increasingly stringent demands on the efficiency and power density of AC-DC converters. Power factor correction (PFC) technology, as the front-end circuit of AC-DC converters, is crucial for suppressing grid current harmonics, improving energy utilization, and enhancing the grid-side power factor. Traditional PFC schemes often employ a boost topology with a diode rectifier bridge at its input; however, this rectifier bridge introduces conduction losses from at least two diodes during any half-cycle, severely limiting the overall efficiency improvement.

[0003] Totem-pole bridgeless PFC achieves synchronous rectification by replacing the slow diodes in traditional Boost PFC circuits with controllable, low-conduction-loss switching transistors (such as MOSFETs), eliminating the need for a diode rectifier bridge. Through a clever control strategy, it ensures that the converter current flows through the path of lowest on-resistance in both the positive and negative AC half-cycles, theoretically minimizing conduction losses. Therefore, due to its simple topology, high power density, and high efficiency, totem-pole bridgeless PFC is widely used in high-end applications with stringent efficiency and power density requirements, such as server and data center power supplies, 5G communication base stations, industrial power supplies, DC fast charging stations for new energy vehicles, and high-end consumer electronics devices. It is a key component in building green and efficient energy systems.

[0004] However, the dynamic performance of totem-pole bridgeless PFC, namely its transient response capability, has become a key technical bottleneck restricting its reliability and application scope. Totem-pole bridgeless PFC typically employs the traditional Average Current Mode (ACM) control method, namely dual closed-loop control (outer loop for output voltage and inner loop for input current). The outer voltage loop is responsible for maintaining the stability of the DC bus voltage, and its bandwidth is strictly limited by twice the power frequency ripple (100Hz / 120Hz). If the bandwidth is set too high, the control system will attempt to suppress this power frequency ripple, leading to severe distortion of the input current and a reduction in the power factor; if the bandwidth is set too low, the system's response to load changes or input voltage drops will become sluggish. When the load undergoes a step change (e.g., a server CPU suddenly enters full-load computing from an idle state), the slow voltage loop response can cause a large overshoot or undershoot in the DC bus voltage: overshoot may damage capacitors and even power devices in downstream circuits; while undershoot may cause system malfunctions or even a restart.

[0005] The existing methods for optimizing the transient response performance of totem pole bridgeless PFC are as follows:

[0006] ① Introduce load feedforward in the control loop: By detecting changes in load current, the load current is directly fed forward to the control signal to quickly compensate for power deficits or surpluses. This method is effective, but it increases the complexity and cost of the detection circuit, and the accuracy of the feedforward quantity is sensitive to the compensation effect, making it difficult to achieve optimal calibration in practical applications.

[0007] ② Using nonlinear control methods: Based on the totem pole bridgeless PFC topology, mathematical modeling is performed, and sliding mode control, model predictive control and other schemes are studied; however, the above nonlinear control schemes have problems such as large computational load, need for accurate modeling of the converter and high software cost, which limit engineering applications.

[0008] ③ Use of notch filters and filters: Use a digital notch filter to filter out the double power frequency ripple in the output voltage and set a high-bandwidth voltage outer loop controller to improve transient response speed; however, this method requires the use of a digital notch filter, and its parameter design and software programming increase the difficulty of digital implementation of the method.

[0009] ④ Use adaptive control methods: Adaptive control (such as neural network control, fuzzy proportional-integral control) is adopted. The controller parameters can be automatically adjusted online according to the system operating status (such as load size, input voltage) to keep the system operating under the best dynamic performance. Although adaptive control methods can cope with a wide range of operating point changes, the algorithms are complex, and the stability analysis and implementation are difficult, which limits engineering applications.

[0010] In summary, developing a bridgeless PFC control method for totem poles that can achieve fast transient response performance is an academic and engineering problem that urgently needs to be solved by researchers in this field. Summary of the Invention

[0011] The purpose of this invention is to provide a discrete current-type control method and device for a fast transient response totem-pole bridgeless PFC. When the output load changes, this device can achieve unity power factor and fast transient response control objectives on the converter input side. The control method provided by this invention eliminates the need for a proportional-integral controller, error amplifier, and its compensation network in the voltage control loop. This results in a simple controller design, low software cost, and the achievement of fast transient response control objectives. Furthermore, the input current reference for the current control loop is obtained from the input current reference calculation module, avoiding interference from twice the power frequency ripple of the output voltage. This decoupling of the voltage and current loops enables low input current distortion control, thus possessing significant academic and engineering application value.

[0012] To address the problems of voltage-current loop coupling, input current distortion rate being easily affected by twice the power frequency ripple of the output voltage, and slow transient response in traditional totem-pole bridgeless PFC average current control methods, this invention provides a discrete current control method for fast transient response totem-pole bridgeless PFC. The technical solution of this invention is as follows:

[0013] A discrete current-mode control method for fast transient response totem-pole bridgeless PFC includes the following steps:

[0014] S1. At each sampling period, collect the instantaneous values ​​of the input voltage, input current, output voltage, and output current of the totem pole bridgeless PFC.

[0015] S2. Determine the zero-crossing time and amplitude of the input voltage based on the instantaneous value of the input voltage;

[0016] S3. Based on the input voltage amplitude, the instantaneous input voltage value, the instantaneous output current value, and the output voltage reference value, determine the input current reference signal to achieve unity power factor on the input side of the totem pole bridgeless PFC;

[0017] S4. Determine the high and low input current coefficients based on the maximum and minimum average output voltage allowed by the totem pole bridgeless PFC.

[0018] S5. Determine the high and low input current references based on the input current reference signal and high and low input current coefficients that achieve unity power factor on the input side of the bridgeless PFC of the totem pole.

[0019] S6. Set voltage loop: When the input voltage crosses zero, sample the output voltage and compare it with the output voltage reference value. Based on the comparison result, select the valid input current reference signal from the high and low input current reference signals as the given value of the current loop.

[0020] S7. Set up the current loop: At each sampling period, subtract the absolute value of the input current from the effective input current reference signal, and obtain the effective duty cycle of the totem pole bridgeless PFC through the proportional-integral (PI) controller.

[0021] S8. Based on the effective duty cycle, the control signal of the switching device of the totem pole bridgeless PFC is obtained through the driving circuit, and the totem pole bridgeless PFC is controlled to achieve the input-side unity power factor and fast transient response control target.

[0022] Preferably, the input current reference signal for achieving unity power factor on the input side of the totem pole bridgeless PFC includes:

[0023] The input current reference signal is obtained based on the input voltage amplitude, instantaneous input voltage value, instantaneous output current value, and output voltage reference value of the totem pole bridgeless PFC.

[0024] Preferably, the high and low input current coefficients include:

[0025] The high and low input current coefficients are obtained based on the maximum and minimum average output voltages allowed by the totem pole bridgeless PFC.

[0026] Preferably, the high and low input current references include:

[0027] Based on the input current reference signal that achieves unity power factor on the input side of the totem pole bridgeless PFC and the high and low input current coefficients, the high and low input current references are obtained.

[0028] Preferably, the effective input current reference signal output by the voltage loop, i.e., the current loop setpoint, includes:

[0029] Based on the comparison between the output voltage and the output voltage reference value, a valid input current reference signal is selected from the high and low input current reference signals: when the output voltage is less than the output voltage reference value, the high input current reference signal is selected as the valid input current reference signal; otherwise, the low input current reference signal is selected as the valid input current reference signal.

[0030] Preferably, the effective duty cycle of the current loop output includes:

[0031] The effective duty cycle of the current loop output is obtained by subtracting the absolute value of the input current from the effective input current reference signal and passing it through a proportional-integral (PI) controller.

[0032] Preferably, the switching device control signal of the totem pole bridgeless PFC includes:

[0033] Based on the effective duty cycle, the effective duty cycle of the totem pole bridgeless PFC is obtained through the driving circuit.

[0034] This invention proposes a discrete current-mode control method for fast transient response totem-pole bridgeless PFC, as detailed below:

[0035] Based on the instantaneous value of the input voltage, determine the zero-crossing time and amplitude of the input voltage; based on the input voltage amplitude, instantaneous value of the input voltage, instantaneous value of the output current, and reference value of the output voltage, determine the input current reference signal for achieving unity power factor on the input side of the totem-pole bridgeless PFC; based on the maximum and minimum allowable average output voltage of the totem-pole bridgeless PFC, determine the high and low input current coefficients; based on the input current reference signal for achieving unity power factor on the input side of the converter and the high and low input current coefficients, determine the high and low input current references; set up a voltage loop: when the input voltage crosses zero... At each sampling period, the sampled output voltage is compared with the output voltage reference value. Based on the comparison result, a valid input current reference signal is selected from the high and low input current reference signals as the setpoint for the current loop. The current loop is set up by subtracting the absolute value of the input current from the valid input current reference signal at each sampling period and obtaining the effective duty cycle of the converter through a proportional-integral (PI) controller. Based on the effective duty cycle, the switching device control signal of the totem-pole bridgeless PFC is obtained through the drive circuit, controlling the totem-pole bridgeless PFC to achieve the input-side unity power factor and fast transient response control objectives. This control method eliminates the need for a proportional-integral controller, error amplifier, and its compensation network in the voltage control loop, resulting in a simple controller design, low software cost, and the ability to achieve fast transient response control. Furthermore, the input current reference of the current control loop provided by this invention is obtained by the input current reference calculation module and is not affected by the output voltage's double power frequency ripple interference, achieving decoupling between the voltage loop and the current loop. Therefore, it can achieve the low input current distortion control objective and has certain academic and engineering application value.

[0036] In addition, the present invention also provides a discrete current-type control device for fast transient response totem pole bridgeless PFC, which has the same beneficial effects as the aforementioned discrete current-type control method for fast transient response totem pole bridgeless PFC. Attached Figure Description

[0037] To more clearly illustrate the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the following drawings are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram of the structure of a discrete current-type control device for a fast transient response totem pole bridgeless PFC provided in an embodiment of the present invention;

[0039] Figure 2 This is a voltage loop control flowchart of a discrete current-type control method for a fast transient response totem pole bridgeless PFC provided in an embodiment of the present invention;

[0040] Figure 3 This is an embodiment of the present invention providing an operating condition (input voltage RMS value U). in =110V, input voltage frequency 50Hz, output voltage U o =400V, output power P o =300W) instantaneous output voltage U o Steady-state time-domain simulation waveforms;

[0041] Figure 4 This is an embodiment of the present invention providing an operating condition (input voltage RMS value U). in =110V, input voltage frequency 50Hz, output voltage U o =400V, output power P o Steady-state time-domain simulation waveform of voltage loop control flag bit (300W);

[0042] Figure 5 This is an embodiment of the present invention providing an operating condition (input voltage RMS value U). in =110V, input voltage frequency 50Hz, output voltage U o =400V, output power P o =300W) effective input current reference i inrefe Time-domain simulation waveform;

[0043] Figure 6 This is an embodiment of the present invention providing an operating condition (input voltage RMS value U). in =110V, input voltage frequency 50Hz, output voltage U o =400V, output power P o =300W) instantaneous absolute value of input current |i in |Time-domain simulation waveform;

[0044] Figure 7 This is an embodiment of the present invention providing an operating condition (input voltage RMS value U). in =110V, input voltage frequency 50Hz, output voltage U o =400V, output power P oThe instantaneous value of the input current i (e.g., 300W) in Time-domain simulation waveform;

[0045] Figure 8 This is an embodiment of the present invention providing an operating condition (input voltage RMS value U). in =110V, input voltage frequency 50Hz, output voltage U o =400V, output power P o The instantaneous input voltage value u of (300W) in Time-domain simulation waveform;

[0046] Figure 9 This is an embodiment of the present invention providing a load switching condition (input voltage RMS value U) in =110V, input voltage frequency 50Hz, output voltage U o =400V, output power P o The instantaneous output voltage U (from 150W to 300W) o Time-domain simulation waveform;

[0047] Figure 10 This is an embodiment of the present invention providing a load switching condition (input voltage RMS value U) in =110V, input voltage frequency 50Hz, output voltage U o =400V, output power P o The instantaneous value of the input current i (from 150W to 300W) in Time-domain simulation waveform;

[0048] Figure 11 This is an embodiment of the present invention providing a load switching condition (input voltage RMS value U) in =110V, input voltage frequency 50Hz, output voltage U o =400V, output power P o The instantaneous input voltage u (from 150W to 300W) in Time-domain simulation waveform;

[0049] Figure 12 When using the traditional Average Current Mode (ACM) control method, under a load switching condition (input voltage RMS value U), in =110V, input voltage frequency 50Hz, output voltage U o =400V, output power P o The instantaneous output voltage U (from 150W to 300W) o Time-domain simulation waveform;

[0050] Figure 13 When using the traditional Average Current Mode (ACM) control method, under a load switching condition (input voltage RMS value U), in =110V, input voltage frequency 50Hz, output voltage U o =400V, output power P o The instantaneous value of the input current i (from 150W to 300W) in Time-domain simulation waveform;

[0051] Figure 14 When using the traditional Average Current Mode (ACM) control method, under a load switching condition (input voltage RMS value U), in =110V, input voltage frequency 50Hz, output voltage U o =400V, output power P o The instantaneous input voltage u (from 150W to 300W) in Time-domain simulation waveform. Detailed Implementation

[0052] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present invention.

[0053] The core of this invention is to provide a discrete current-type control method for a totem-pole bridgeless power distribution (PFC) with fast transient response. When the output load of the totem-pole bridgeless PFC changes rapidly, it can respond quickly and suppress the output voltage overshoot or undershoot. This control method eliminates the need for a proportional-integral controller, error amplifier, and compensation network in the voltage control loop, resulting in a simple controller design, low software cost, and the ability to achieve fast transient response control. Furthermore, the input current reference for the current control loop is obtained from an input current reference calculation module, avoiding interference from twice the power frequency ripple of the output voltage. This decouples the voltage and current loops, thus achieving low input current distortion control and possessing significant academic and engineering application value.

[0054] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0055] The output voltage and input current control targets of a totem-pole bridgeless PFC are typically achieved through Average Current Mode (ACM) control, i.e., a dual-loop control method (output voltage outer loop and input current inner loop). However, the double-frequency ripple in the output voltage is coupled to the input current loop through the controller of the output voltage outer loop, causing input current distortion. To reduce the degree of input current distortion, the controller of the output voltage outer loop needs to be set to a lower bandwidth, resulting in a slow transient response of the converter.

[0056] To optimize the transient response performance of totem-pole bridgeless PFC and reduce input current distortion, the following control methods can typically be used:

[0057] ① Introducing load feedforward in the control loop: By detecting changes in the load current of a totem-pole bridgeless PFC, the load is directly fed forward to the control signal to quickly compensate for power deficits or surpluses. This control method is highly effective, but it increases the complexity of the detection circuit and hardware costs. Furthermore, the accuracy of the feedforward quantity is sensitive to the compensation effect, making it difficult to achieve optimal calibration in practical engineering applications.

[0058] ② Using nonlinear control methods: Based on the totem pole bridgeless PFC topology, mathematical modeling is performed, and sliding mode control, model predictive control and other schemes are studied; however, the above nonlinear control schemes have problems such as large computational load, need for accurate modeling of the converter and high software cost, which limit practical engineering applications.

[0059] ③ Use of notch filters and filters: Use a notch filter to filter out the double power frequency ripple in the output voltage of the totem pole bridgeless PFC, and set a high-bandwidth voltage outer loop controller to improve transient response performance; however, this method requires the use of a digital notch filter, and its parameter design and software programming increase the difficulty of implementation.

[0060] ④ Use adaptive control methods: Adaptive control (such as neural network control, fuzzy proportional-integral control) is adopted. The controller parameters can be automatically adjusted online according to the system operating status (such as load size, input voltage) to keep the system operating under the best dynamic performance. Although adaptive control methods can cope with a wide range of operating point changes, the control algorithm is complex, and the stability analysis and implementation are difficult, which limits engineering applications.

[0061] Based on the above-mentioned research status, the embodiments of the present invention mainly provide a discrete current-type control method and device for fast transient response totem pole bridgeless PFC.

[0062] Figure 1 This is a schematic diagram of a discrete current-type control device for a fast transient response totem-pole bridgeless PFC provided in an embodiment of the present invention; as shown. Figure 1As shown, in addition to the totem-pole bridgeless PFC, the device also requires a discrete current controller: The discrete current controller includes the input voltage u in Zero crossing detection and amplitude U m Calculation module, voltage and current sampling and analog-to-digital conversion module, input current reference signal i inref Calculation module, high and low input current coefficient K IH K IL Calculation module, high and low input current reference i inrefH i inrefL The system comprises a calculation module, a voltage loop module, a current loop module, and a drive circuit module; the voltage loop module includes a comparator module and an effective input current reference signal i. inrefe The generation module; the current loop module includes a subtractor and a PI controller.

[0063] Figure 2 A voltage loop control flowchart for a discrete current-type control method of a fast transient response totem-pole bridgeless PFC provided in an embodiment of the present invention is shown below. Figure 2 As shown, the process is as follows:

[0064] Step 1: At each sampling period, acquire the instantaneous input voltage value u of the totem-pole bridgeless PFC. in Instantaneous value of input current i in Instantaneous output voltage U o and instantaneous value of output current I o ;

[0065] Step 2: Based on the instantaneous value of the input voltage u in Determine the zero-crossing time of the input voltage and the amplitude U of the input voltage. m ;

[0066] Step 3: Based on the input voltage amplitude U m Input voltage instantaneous value u in Instantaneous value of output current I o Output voltage reference value U oref Determine the input current reference signal i for achieving unity power factor on the input side of the totem pole bridgeless PFC. inref ,as follows:

[0067]

[0068] Step 4: Based on the maximum allowable average output voltage U of the totem pole bridgeless PFC. omax and minimum average output voltage U omin Determine the high and low input current coefficients K IH K IL ,as follows:

[0069]

[0070] Step 5: Based on the input current reference signal i that achieves unity power factor on the converter input side. inref and high and low input current coefficients K IH K IL Determine the high and low input current references i inrefH i inrefL ,as follows:

[0071]

[0072] Step Six: Set up the voltage loop: At the input voltage u in At the zero crossing time, the sampled output voltage U o With output voltage reference value U oref Compare the high and low input current reference signals i based on the comparison results. inrefH i inrefL Select the valid input current reference signal i inrefe As a given value for the current loop, it is as follows:

[0073]

[0074] like Figure 1 As shown in the figure, the implementation steps of the current loop of the discrete current-type control method of fast transient response totem pole bridgeless PFC provided by the embodiment of the present invention are as follows:

[0075] Step 7: Set up the current loop: At each sampling period, input the effective current reference signal i inrefe With input current |i in The absolute values ​​are subtracted, and the effective duty cycle of the converter is obtained through a proportional-integral (PI) controller;

[0076] Step 8: Based on the effective duty cycle, obtain the switching device control signal v of the totem pole bridgeless PFC through the drive circuit. g1 ~v g4 The switching devices S1~S4 of the totem pole bridgeless PFC are controlled to achieve the control objectives of unity power factor and fast transient response on the input side.

[0077] For an introduction to the discrete current-type control device of fast transient response totem pole bridgeless PFC provided by the present invention, please refer to the above method embodiments. The present invention will not be described in detail again, but has the same beneficial effects as the discrete current-type control method of fast transient response totem pole bridgeless PFC described above.

[0078] Figures 3-8 This is a steady-state operating condition (input voltage RMS value U) provided in an embodiment of the present invention. in=110V, input voltage frequency 50Hz, output voltage U o =400V, output power P o =300W), simulation results of a discrete current-mode control method for a fast transient response totem pole bridgeless PFC.

[0079] Figures 3-8 In the simulation shown, the parameters of the totem pole bridgeless PFC circuit include: the effective value of the input AC voltage U. in =110V, output voltage U o =110V, output power P o =300W, switching frequency 50kHz, input filter inductor L=2mH, output filter capacitor C=220uF; the control parameters of the discrete current type control method include: K IH =1.02, K IL =0.98.

[0080] Figure 3 This is an embodiment of the present invention providing an operating condition (input voltage RMS value U). in =110V, input voltage frequency 50Hz, output voltage U o =400V, output power P o =300W) instantaneous output voltage U o Steady-state time-domain simulation waveforms. Figure 3 It can be seen that, using the discrete current-type control method of the present invention, the output voltage U o For the output voltage reference U oref The follow-up situation is good.

[0081] Figure 4 This is an embodiment of the present invention providing an operating condition (input voltage RMS value U). in =110V, input voltage frequency 50Hz, output voltage U o =400V, output power P o The steady-state time-domain simulation waveform of the voltage loop control flag bit (300W). Figures 3-4 It can be seen that at the moment when the input voltage crosses zero, when the output voltage U o Less than the output voltage reference U oref When the voltage loop control flag is set to 1, the flag is set to 0.

[0082] Figure 5 This is an embodiment of the present invention providing an operating condition (input voltage RMS value U). in =110V, input voltage frequency 50Hz, output voltage U o =400V, output power P o =300W) effective input current reference i inrefeTime-domain simulation waveform. (From...) Figures 4-5 It can be seen that when the voltage loop control flag is 1, the low input current reference signal i is selected. inrefL i, as the effective current reference signal inrefe Otherwise, select a high-current reference signal i. inrefH .

[0083] Figure 6 This is an embodiment of the present invention providing an operating condition (input voltage RMS value U). in =110V, input voltage frequency 50Hz, output voltage U o =400V, output power P o =300W) instantaneous absolute value of input current |i in |Time-domain simulation waveform diagram. (From...) Figures 5-6 It can be seen that the absolute value of the input current |i in |Can follow the effective current reference signal i well inrefe .

[0084] Figure 7 This is an embodiment of the present invention providing an operating condition (input voltage RMS value U). in =110V, input voltage frequency 50Hz, output voltage U o =400V, output power P o The instantaneous value of the input current i (e.g., 300W) in Time-domain simulation waveform. (From...) Figure 7 It can be seen that, using the discrete current-type control method of the present invention, the input current i in The waveform has a high degree of sinusoidalization and a low degree of waveform distortion.

[0085] Figure 8 This is an embodiment of the present invention providing an operating condition (input voltage RMS value U). in =110V, input voltage frequency 50Hz, output voltage U o =400V, output power P o The instantaneous input voltage value u of (300W) in Time-domain simulation waveform. (From...) Figures 7-8 It can be seen that, using the discrete current-type control method of the present invention, the input current i in With input voltage u in By ensuring phase consistency, the unity power factor control target on the input side of the converter can be achieved.

[0086] Figures 9-11 This invention provides an embodiment of a load transient condition (input voltage RMS value U) in =110V, input voltage frequency 50Hz, output voltage U o =400V, output power Po Transient simulation results of a discrete current-mode control method for a fast transient response totem pole bridgeless PFC (from 150W to 300W).

[0087] Figures 9-11 In the simulation shown, the parameters of the totem pole bridgeless PFC circuit are... Figures 3-8 The parameters shown in the simulation are the same; the control parameters of the discrete current-mode control method include: K IH =1.02, K IL =0.98.

[0088] Figure 9 This is an embodiment of the present invention providing a load switching condition (input voltage RMS value U) in =110V, input voltage frequency 50Hz, output voltage U o =400V, output power P o The instantaneous output voltage U (from 150W to 300W) o Time-domain simulation waveform. (From...) Figure 9 It can be seen that when the output power P o When the power output changes from 150W to 300W, the discrete current control method of this invention is used to output the voltage U. o The load transient response time is 80ms, indicating a fast transient response speed; the output voltage U o There was no obvious downward pressure.

[0089] Figure 10 This is an embodiment of the present invention providing a load switching condition (input voltage RMS value U) in =110V, input voltage frequency 50Hz, output voltage U o =400V, output power P o The instantaneous value of the input current i (from 150W to 300W) in Time-domain simulation waveform. (From...) Figure 10 It can be seen that the output power P o When the power output changes from 150W to 300W, the input current i in The amplitude changed from 2.2A to 4.4A.

[0090] Figure 11 This is an embodiment of the present invention providing a load switching condition (input voltage RMS value U) in =110V, input voltage frequency 50Hz, output voltage U o =400V, output power P o The instantaneous input voltage u (from 150W to 300W) in Time-domain simulation waveform.

[0091] Figures 12-14When using the traditional Average Current Mode (ACM) control method, under a load switching condition (input voltage RMS value U), in =110V, input voltage frequency 50Hz, output voltage U o =400V, output power P o Transient simulation results (from 150W to 300W);

[0092] Figures 12-14 In the simulation shown, the parameters of the totem pole bridgeless PFC circuit are... Figures 3-8 The parameters are the same in the simulation shown; the control parameters of the traditional average current mode control include: the proportional coefficient of the voltage loop PI controller is 0.0005, and the integral coefficient is 0.005.

[0093] Figure 12 When using the traditional Average Current Mode (ACM) control method, under a load switching condition (input voltage RMS value U), in =110V, input voltage frequency 50Hz, output voltage U o =400V, output power P o The instantaneous output voltage U (from 150W to 300W) o Time-domain simulation waveform. (From...) Figure 12 It can be seen that when the output power P o When switching from 150W to 300W, using the traditional average current analog-to-digital control method, the output voltage U o The load transient response time is 500ms, which is slow; the output voltage U o There is a significant undershoot phenomenon, with a minimum undershoot value of U. o =380V.

[0094] Figure 13 When using the traditional Average Current Mode (ACM) control method, under a load switching condition (input voltage RMS value U), in =110V, input voltage frequency 50Hz, output voltage U o =400V, output power P o The instantaneous value of the input current i (from 150W to 300W) in Time-domain simulation waveform. (From...) Figure 13 It can be seen that the output power P o When the power output changes from 150W to 300W, the input current i in The amplitude changed from 2.2A to 4.4A.

[0095] Figure 14 When using the traditional Average Current Mode (ACM) control method, under a load switching condition (input voltage RMS value U), in =110V, input voltage frequency 50Hz, output voltage U o =400V, output power P o The instantaneous input voltage u (from 150W to 300W) in Time-domain simulation waveform.

[0096] Figure 9 and Figure 12 The simulation results shown indicate that at the output power P o When transient transitions occur, the discrete current-type control method of totem-pole bridgeless PFC proposed in this invention can improve the transient response speed (output voltage U) during such transitions. o The transient response time is reduced from 500ms to 80ms, and the output voltage U caused by sudden load is reduced. o Undershoot (output voltage U) o The minimum down-thrust value has been increased from 380V to 393V, which effectively improves the transient response performance of the totem pole bridgeless PFC.

[0097] The above verification process demonstrates the effectiveness and feasibility of the discrete current-type control method for a fast transient response totem pole bridgeless PFC provided in this embodiment.

[0098] The foregoing has provided a detailed description of the discrete current-type control method and apparatus for a fast transient response totem-pole bridgeless PFC provided by the present invention. The various embodiments in the specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A discrete current-mode control method for totem-pole bridgeless PFC, characterized in that, The method comprises the following steps: S1, at each sampling cycle time, collect the input voltage instantaneous value u of the totem column bridgeless PFC in , input current instantaneous value i in , output voltage instantaneous value U o And output current instantaneous value I o , and define the output voltage reference value U oref ; S2, determining the input voltage zero-crossing time and the input voltage amplitude U in based on the input voltage instantaneous value u m ; S3, according to the input voltage amplitude U m , input voltage instantaneous value u in , output current instantaneous value I o , output voltage reference value U oref , determine the input current reference signal i inref : ， S4, the maximum average output voltage U allowed by the Totem Pole Bridgeless PFC omax and the minimum average output voltage U omin , determine the high, low input current coefficient K IH , K IL : ， S5、According to the input current reference signal i inref and high, low input current coefficient K IH , K IL , determine high, low input current reference i inrefH , i inrefL : ， S6, setting voltage loop: at input voltage u in Zero-crossing time, the sampling output voltage U o With the output voltage reference value U oref Comparison, according to the comparison result, from high, low input current reference signal i inrefH , i inrefL The effective input current reference signal i inrefe , as the given value of the current loop: ， S7, set current loop: at each sampling period, the effective input current reference signal i inrefe is subtracted from the input current absolute value |i in , and the effective duty cycle D of the totem-pole bridgeless PFC is obtained through a proportional-integral (PI) controller e ; S8. Based on the effective duty cycle D e The control signals v of the switching devices S1~S4 of the totem pole bridgeless PFC are obtained through the driving circuit. g1 ~v g4 The bridgeless PFC with totem pole control achieves the input-side unity power factor and fast transient response control objectives.

2. A discrete current-mode control apparatus for fast transient response totem-pole bridgeless PFC, for the discrete current-mode control method of totem-pole bridgeless PFC of claim 1, characterized by, The method comprises the following steps: The method comprises the following steps: voltage current sampling and analog-digital conversion module, input voltage zero-crossing detection and amplitude calculation module, input current reference signal module, high and low input current coefficient calculation module, high and low input current reference calculation module, voltage loop control module, current loop control module, and driving circuit module. The voltage and current sampling and analog-digital conversion module is used for collecting input voltage instantaneous value u of the totem pole bridgeless PFC in , input current instantaneous value i in , output voltage instantaneous value U o , and output current instantaneous value I o ; The input voltage zero-crossing detection and amplitude calculation module is configured to detect the input voltage u in The zero-crossing moment of the input voltage u in The amplitude U m ; The input current reference signal module is configured to calculate an input current reference signal ; The high and low input current coefficient calculation module is configured to calculate high and low input current coefficients ; The high-low input current reference calculation module is configured to calculate high and low input current references i inrefH 、 inrefL : ; The voltage loop control module is used to input high and low current reference signals i inrefH i inrefL Select the valid input current reference signal i inrefe , as a given value for the current loop: ; The current loop control module is configured to, at each sampling period, subtract the absolute value of the input current |i inrefe from the effective input current reference signal i in and obtain the effective duty ratio of the totem-pole bridgeless PFC through a proportional-integral (PI) controller. The drive circuit module is used for obtaining control signals v of switching devices S1-S4 of the totem-pole bridgeless PFC g1 ~v g4 , and controlling the totem-pole bridgeless PFC.

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