Current sampling method of totem PFC circuit and electronic equipment thereof

Abstract

The embodiment of the invention discloses a current sampling method of a totem PFC (Power Factor Correction) circuit and electronic equipment thereof. The method comprises the following steps: setting an initial zero current reference value; in the non-PWM driving stage of the totem PFC circuit, sampling the output voltage of the Hall sensor through an analog-to-digital converter to obtain a sampling value; adjusting a zero current reference value based on the sampling value; in the PWM driving stage of the totem PFC circuit, sampling the output voltage of the Hall sensor through an analog-to-digital converter to obtain a working sampling value; and obtaining a current conditioning signal based on the working sampling value and the zero current reference value according to a polarity signal of the input voltage of the totem PFC circuit. By means of the mode, under the condition that the Hall sensor without zero current reference is adopted, the accurate zero current reference value can be obtained in an indirect mode, current sampling is achieved, the number of used analog-to-digital converters is reduced, and the circuit cost and the design difficulty are reduced.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of electronic technology, and in particular to a current sampling method for a totem PFC circuit and an electronic device thereof. Background Technology

[0002] Totem PFC (Power Factor Correction) circuits are increasingly widely used in the power supply field due to their high efficiency. Because of their unique operating principle, Totem PFC typically uses Hall effect sensors for current sampling. By sampling the current flowing through the inductor using the Hall effect sensor, closed-loop control of the system can be achieved.

[0003] During the positive half-cycle of the input voltage, the inductor current flows into the Hall sensor's IP+ terminal and out through the IP- terminal; during the negative half-cycle of the input voltage, the inductor current flows into the Hall sensor's IP- terminal and out through the IP+ terminal.

[0004] In traditional Hall effect sampling, Hall effect devices with a zero-current reference are typically used. These devices have a dedicated zero-current reference output terminal VZCR. The relationship between their output voltage VOUT and the zero-current reference voltage VZCR and sampling current iL is: VOUT = VZCR + k×iL, where k is the Hall current-to-voltage conversion ratio. Thus, a current signal with positive and negative variations, after passing through the Hall sensor, can be transformed into a voltage signal superimposed with the bias voltage VZCR, which is then transmitted to the analog-to-digital converter (ADC) for sampling.

[0005] The Totem PFC control system samples VOUT and VZCR using an ADC, obtaining Isample and Izero, which are then sent to the current conditioning module. The current conditioning module processes Isample and Izero according to the polarity signal POL of the input voltage: when the input voltage is positive, the current conditioning signal Iadjust = Isample - Izero; when the input voltage is negative, Iadjust = Izero - Isample. In this way, Iadjust represents the absolute value of the inductor current iL, used for closed-loop control of the system.

[0006] While Hall sensors with zero-current references offer greater control convenience, Hall sensors without zero-current references have a more significant price advantage, reducing overall system cost and design complexity. Hall sensors without zero-current references no longer have a dedicated zero-current reference signal VZCR output.

[0007] However, for the Totem PFC system which uses a Hall sensor without a zero-current reference, the traditional current sampling strategy with a Hall sensor with a zero-current reference cannot be applied because the zero-current reference information cannot be obtained directly. The system cannot obtain the true absolute value of the inductor current, thus affecting the closed-loop control performance of the system. Summary of the Invention

[0008] The main technical problem solved by the embodiments of the present invention is to provide a current sampling method for a totem PFC circuit and an electronic device thereof, which can solve at least some of the defects existing in the existing totem PFC circuit.

[0009] In a first aspect, embodiments of the present invention provide a current sampling method for a totem PFC circuit, the totem PFC circuit including an analog-to-digital converter and a Hall sensor, comprising: setting an initial zero-current reference value; during the non-PWM drive phase of the totem PFC circuit, sampling the output voltage of the Hall sensor through the analog-to-digital converter to obtain a sampled value; adjusting the zero-current reference value based on the sampled value; during the PWM drive phase of the totem PFC circuit, sampling the output voltage of the Hall sensor through the analog-to-digital converter to obtain a working sampled value; and obtaining a current conditioning signal based on the polarity signal of the input voltage of the totem PFC circuit, the working sampled value, and the zero-current reference value.

[0010] Optionally, the initial zero-current reference value is set according to the power supply voltage of the Hall sensor; the initial zero-current reference value corresponds to the digital value of the output voltage of the Hall sensor in the zero-current state after being sampled by the analog-to-digital converter.

[0011] Optionally, the non-PWM drive phase includes a startup detection phase and / or a zero-crossing commutation phase of the totem PFC circuit; in the startup detection phase, when the output voltage of the totem PFC circuit is greater than the input voltage, the output voltage of the Hall sensor is sampled by the analog-to-digital converter; in the zero-crossing commutation phase, when it is determined that the totem PFC circuit is in the zero-crossing commutation range of the input voltage, the output voltage of the Hall sensor is sampled by the analog-to-digital converter.

[0012] Optionally, adjusting the zero-current reference value based on the sampled value includes: setting a zero-current reference filter value, a first filter coefficient k1, and a second filter coefficient k2, where k2 = 1 - k1; updating the zero-current reference filter value according to the formula: zero-current reference filter value = k1 × zero-current reference filter value + k2 × sampled value; and setting the zero-current reference value as the zero-current reference filter value.

[0013] Optionally, obtaining the current conditioning signal based on the working sample value and the zero-current reference value according to the polarity signal of the input voltage of the totem PFC circuit includes: when the polarity signal indicates that the input voltage is positive, the current conditioning signal is equal to the working sample value minus the zero-current reference value; when the polarity signal indicates that the input voltage is negative, the current conditioning signal is equal to the zero-current reference value minus the working sample value.

[0014] Optionally, the aspect further includes limiting the zero-current reference filter value, comprising the following steps: setting a maximum correction amount; when the zero-current reference filter value is greater than the sum of the initial zero-current reference value and the maximum correction amount, limiting the zero-current reference filter value to the sum of the initial zero-current reference value and the maximum correction amount; when the zero-current reference filter value is less than the difference between the initial zero-current reference value and the maximum correction amount, limiting the zero-current reference filter value to the difference between the initial zero-current reference value and the maximum correction amount.

[0015] Optionally, when the limiting process is triggered, a protection operation is performed on the totem PFC circuit, the protection operation including stopping the PWM drive and / or shutting down the system.

[0016] Optionally, the Hall sensor is a Hall sensor without a zero-current reference.

[0017] In a second aspect, embodiments of the present invention provide an electronic device, comprising: at least one processor; at least one network interface communicatively connected to a corresponding processor; and a memory communicatively connected to the at least one processor; wherein the network interface is used to establish a communication connection between the processor and other external devices; the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform a current sampling method for a totem PFC circuit as described in the first aspect.

[0018] Thirdly, embodiments of the present invention provide a non-volatile computer storage medium storing computer-executable instructions, which are executed by one or more processors to enable the one or more processors to perform the current sampling method of the totem PFC circuit as described in the first aspect.

[0019] The beneficial effects of the embodiments of the present invention are as follows: Unlike the prior art, the embodiments of the present invention obtain an accurate zero current reference value indirectly when using a Hall sensor without a zero current reference, thereby achieving current sampling, reducing the number of analog-to-digital converters used, reducing circuit costs and design difficulty. Attached Figure Description

[0020] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0021] Figure 1 This is a topology diagram of a Totem PFC circuit using Hall sampling; Figure 2 The diagram shows the inductor current flow of the PFC circuit during the positive half-cycle of the input voltage. Figure 3 The diagram shows the inductor current flow of the totem PFC circuit during the negative half-cycle of the input voltage. Figure 4 This is a schematic diagram of a Hall element with a zero-current reference; Figure 5 This is a schematic diagram of current sampling using a Totem PFC circuit with a zero-current reference Hall sensor. Figure 6 This is a block diagram of the sampling and conditioning of the current signal in the Totem PFC control system; Figure 7 The relationship between input voltage and polarity signal is shown; Figure 8 This is a schematic diagram of a Hall element without a zero-current reference; Figure 9 It is a sampling and conditioning framework for current signals using a Hall sensor without a zero-current reference; Figure 10 This is a flowchart illustrating a current sampling method for a totem PFC circuit provided in an embodiment of the present invention. Figure 11 This shows the working status of the totem PFC circuit during the startup phase; Figure 12 The zero-crossing commutation interval of the totem PFC circuit is shown; Figure 13 This is a schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. Detailed Implementation

[0022] To facilitate understanding of this application, a more detailed description is provided below with reference to the accompanying drawings and specific embodiments. It should be noted that when an element is described as being "fixed to" another element, it can be directly on the other element, or one or more intermediate elements may exist between them. When an element is described as being "connected" to another element, it can be directly connected to the other element, or one or more intermediate elements may exist between them. The terms "upper," "lower," "inner," "outer," "bottom," etc., used in this specification indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0024] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0025] The technical solutions in this application will be described below with reference to the accompanying drawings.

[0026] In some embodiments of this application, such as Figure 1 The Totem PFC circuit topology using Hall effect sampling shown includes an EMI filter, switching transistors Q1 and Q2, synchronous rectifier diodes SR1 and SR2, inductor L, output capacitor Cout, and a Hall effect sensor. The Totem PFC circuit samples the current flowing through inductor L using the Hall effect sensor to achieve closed-loop control of the system. Closed-loop control refers to a control method that adjusts the circuit's operating state to maintain stable output by detecting the circuit's output parameters and comparing them with desired values.

[0027] Specifically, the Hall sensor has a current inflow port IP+ and a current outflow port IP-. As an example, and not a limitation, at an input voltage V... AC The positive half-cycle, such as Figure 2 As shown, the inductor current i flowing through inductor L L The water flows into the Hall sensor from the IP+ terminal and flows out of the Hall sensor from the IP- terminal. In some embodiments of this application, when the input voltage V... ACThe negative half-cycle, such as Figure 3 As shown, the inductor current i L The direction of flow changes, and the inductor current i L The water flows into the Hall sensor from the IP- terminal and flows out of the Hall sensor from the IP+ terminal.

[0028] Traditional Hall sampling methods use Hall devices with zero-current references, such as... Figure 4 As shown, the Hall element with zero current reference includes a current sampling positive terminal IP+, a current sampling negative terminal IP-, a ground terminal GND, a zero current reference voltage output terminal VZCR, a sampling output signal terminal VOUT, and a chip power supply terminal VCC.

[0029] In some embodiments of this application, such as Figure 5 As shown, in the current sampling principle of the Totem PFC circuit with a zero-current reference Hall sensor, the output voltage VOUT of the Hall sensor is related to the zero-current reference voltage VZCR and the inductor current i. L The relationship between them is: VOUT = VZCR + k×i L , where k is the current-to-voltage conversion ratio of the Hall sensor. As an example and not a limitation, an inductor current signal with positive and negative changes is converted into a voltage signal VOUT superimposed with a bias voltage VZCR after passing through the Hall sensor, and then passed to an analog-to-digital converter (ADC) for sampling, where the ADC is used to convert the analog voltage signal into a digital signal for processing by the control system.

[0030] like Figure 6 As shown, the Totem PFC control system's sampling and conditioning of the current signal includes an analog-to-digital converter (ADC), a current conditioning module, and a control system. Specifically, when the inductor current flows through the Hall sensor, the Hall sensor converts the current signal into a voltage signal VOUT, and simultaneously outputs a reference signal VZCR representing zero current. In some embodiments of this application, the Totem PFC control system samples VOUT and VZCR respectively through the ADC to obtain the sampled value I. sample and zero current reference value I zero The sampled value is then sent to the current conditioning module.

[0031] As an example, and not a limitation, the current conditioning module adjusts according to the input voltage V. AC The polarity signal POL to I sample and I zero The signal is processed to obtain the current conditioning signal I. adjust Closed-loop control for a totem PFC circuit system, wherein the polarity signal POL is used to indicate the positive or negative polarity of the input voltage, and the current conditioning signal I... adjustUsed to characterize the actual magnitude of the inductor current. For example... Figure 7 As shown, the polarity signal POL is related to the input voltage V. AC The relationship is: when the input voltage V AC When positive, the POL signal is 1; when the input voltage V... AC When the value is negative, the POL signal is 0.

[0032] Specifically, when the polarity signal POL is 1, that is, when the input voltage is positive, the current conditioning signal I... adjust equals I sample Subtract I zero When the polarity signal POL is 0, i.e., the input voltage is negative, the current conditioning signal I... adjust equals I zero Subtract I sample In some embodiments of this application, the current conditioning signal I is processed in the manner described above. adjust Capable of representing inductor current i L The absolute value of the value is used for power factor correction and output voltage regulation control in the Totem PFC circuit system.

[0033] While Hall sensors with zero-current references offer greater control convenience, Hall sensors without zero-current references have a more significant price advantage. In some embodiments of this application, Hall sensors without zero-current references can reduce the overall system cost, simplify system design, and are more suitable for cost-sensitive applications.

[0034] Specifically, such as Figure 8 As shown, a Hall element without a zero-current reference includes a current sampling positive terminal IP+, a current sampling negative terminal IP-, a ground terminal GND, a sampling output signal terminal VOUT, and a chip power supply terminal VCC. Compared to a Hall element with a zero-current reference, a Hall element without a zero-current reference no longer has a dedicated zero-current reference signal output terminal VZCR; instead, the original VZCR terminal is set to an empty pin NC (No Connection).

[0035] In some embodiments of this application, for Hall sensors without a zero-current reference, the default zero-current reference bias voltage is VCC / 2, where VCC is the power supply voltage of the Hall sensor. It is easy to understand that when no current flows through the Hall sensor, the output voltage VOUT should theoretically be equal to VCC / 2.

[0036] As an example rather than a limitation, such as Figure 9As shown, the current sampling framework using a Hall sensor without a zero-current reference includes an analog-to-digital converter (ADC), a current conditioning module, and a control system. Specifically, when current flows through the Hall sensor, the Hall sensor converts the current signal into a voltage signal VOUT. In some embodiments of this application, the ADC samples VOUT to obtain a sampled value I. sample The current conditioning module adjusts I based on the polarity signal POL. sample The signal is processed to obtain the current conditioning signal I. adjust Closed-loop control for Totem PFC circuit system.

[0037] It's easy to understand that for a Totem PFC system using a Hall sensor without a zero-current reference, the traditional current sampling strategy with a Hall sensor cannot be directly applied because zero-current reference information cannot be obtained. Specifically, the current conditioning module cannot obtain an accurate zero-current reference value, thus affecting the current conditioning signal I. adjust The accuracy of the circuitry affects the control performance of the Totem PFC circuit system.

[0038] In some embodiments of this application, to address the aforementioned technical problems, a novel current sampling method is proposed for the Totem PFC system employing a Hall sensor without a zero-current reference. This method indirectly obtains accurate zero-current reference information, thereby achieving precise current sampling and system control. A flowchart of this method is shown below. Figure 10 As shown, the specific steps include the following: Step S100: Set the initial zero current reference value.

[0039] In some embodiments of this application, for Hall sensors without a zero-current reference, an initial zero-current reference value is set based on the power supply voltage VCC of the Hall sensor. Specifically, the default zero-current reference bias voltage of a Hall sensor without a zero-current reference is VCC / 2. When no current flows through the Hall sensor, its output voltage VOUT is theoretically equal to VCC / 2.

[0040] It is easy to understand that the control system sets an internal initial zero-current reference value Izero_initial based on the aforementioned theoretical value. As an example, and not a limitation, this initial zero-current reference value corresponds to the digital value of the Hall sensor's output voltage in a zero-current state after sampling by an analog-to-digital converter. Specifically, if the resolution of the analog-to-digital converter is N bits and the reference voltage is Vref, then the initial zero-current reference value can be expressed as: Izero_initial = (VCC / 2) × (2^N) / Vref. In some embodiments of this application, the initial zero-current reference value provides a benchmark for subsequent zero-current reference value adjustment, ensuring that the sampling system has a reasonable initial operating point.

[0041] Step S200: During the non-PWM drive phase of the Totem PFC circuit, the output voltage of the Hall sensor is sampled by an analog-to-digital converter to obtain the sampled value.

[0042] By way of example and not limitation, the non-PWM drive phase of the Totem PFC circuit refers to the operating phase in which the Totem PFC circuit does not issue a pulse width modulation drive signal. In some embodiments of this application, the non-PWM drive phase mainly includes the start-up detection phase and the zero-crossing commutation phase, in which the Hall sensor has virtually no current flowing through it or the current is extremely small, and can be approximately considered to be in a zero-current state.

[0043] Specifically, during the startup detection phase, when the input voltage VAC is powered on, the Totem PFC circuit enters the startup detection state. During this period, the Totem PFC circuit will not emit PWM pulse signals. It is easy to understand that when the output voltage VBUS, after uncontrolled rectification, is approximately equal to the peak value of the input voltage VAC, as long as the input voltage VAC is less than the output voltage VBUS, no current will flow through the Hall sensor. In some embodiments of this application, when it is determined that the output voltage VBUS is greater than the input voltage VAC, the analog-to-digital converter is activated to sample the output voltage VOUT of the Hall sensor. The obtained sample value can be approximated as a zero-current reference value.

[0044] As an example and not a limitation, during the zero-crossing commutation phase, when the input voltage VAC approaches zero, the Totem PFC circuit is in the zero-crossing commutation range, and at this time, the Totem PFC circuit will not emit a PWM pulse signal. Specifically, within the zero-crossing commutation range, since the input voltage is close to zero, the current flowing through the inductor is also close to zero, and the Hall sensor has virtually no current flowing through it. In some embodiments of this application, when it is determined that the Totem PFC circuit is in the zero-crossing commutation range, the output voltage of the Hall sensor is sampled by an analog-to-digital converter, and the obtained sampled value can also be used to update the zero-current reference value.

[0045] Step S300: Adjust the zero current reference value based on the sampled value.

[0046] It is easy to understand that due to fluctuations in the power supply voltage VCC of the Hall sensor, as well as the influence of factors such as temperature and aging, the zero point of the Hall sensor may drift. Therefore, it is necessary to dynamically adjust the zero current reference value based on the actual sampled value. In some embodiments of this application, a filtering algorithm is used to update and adjust the zero current reference value in real time.

[0047] Specifically, set the zero-current reference filter value I. zero_filterThe filter coefficients are a first filter coefficient k1 and a second filter coefficient k2, where k2 = 1 - k1. As an example and not a limitation, the value of the filter coefficient k1 is typically between 0.9 and 0.99, used to control the response speed and stability of the filter. In some embodiments of this application, according to the filtering formula: zero current reference filter value I... zero_filter = k1×zero current reference filter value + k2×sampled value, update the zero current reference filter value.

[0048] It is easy to understand that the above filtering algorithm uses low-pass filtering, which can effectively suppress the influence of sampling noise while maintaining the ability to track zero-point drift. Specifically, a larger k1 value makes the filter more resistant to interference, but the response speed is slower; a smaller k1 value makes the filter respond faster, but the resistant to interference is weaker. In some embodiments of this application, the updated zero-current reference filter value is set as the zero-current reference value, i.e., I. zero = I zero_filter This enables dynamic adjustment of the zero current reference value.

[0049] Step S400: In the PWM drive stage of the Totem PFC circuit, the output voltage of the Hall sensor is sampled by an analog-to-digital converter to obtain the working sample value.

[0050] As an example and not a limitation, the PWM drive stage of the Totem PFC circuit refers to the stage in which the Totem PFC circuit operates normally and issues a pulse width modulation drive signal to control the switching transistors to turn on and off. In some embodiments of this application, during the PWM drive stage, switching transistors Q1 and Q2 switch on and off according to the PWM signal, and an alternating inductor current flows through inductor L. The Hall sensor detects the inductor current and converts it into a corresponding voltage signal.

[0051] Specifically, during the PWM drive phase, the magnitude and direction of the inductor current change according to the operating state of the PFC circuit. The output voltage VOUT of the Hall sensor contains current information and zero-current bias information. It is easy to understand that the analog-to-digital converter samples the output voltage VOUT of the Hall sensor in real time, and the obtained working sample value reflects the actual current flowing through the Hall sensor at the current moment. In some embodiments of this application, the sampling timing of the working sample value is typically selected at a specific moment within the PWM cycle, such as the midpoint of the switching transistor's on-time or off-time, to obtain stable and reliable current information.

[0052] As an example, and not a limitation, to improve sampling accuracy, multiple samples can be taken within each PWM cycle and averaged, or synchronous sampling can be used to keep the data synchronized with the PWM signal. Specifically, the magnitude of the working sampled value depends on parameters such as the amplitude of the current flowing through the Hall sensor, the sensitivity of the Hall sensor, and the resolution of the analog-to-digital converter.

[0053] Step S500: Based on the polarity signal of the input voltage of the totem PFC circuit, obtain the current conditioning signal based on the working sample value and the zero current reference value.

[0054] Specifically, because the inductor current flows differently during the positive and negative half-cycles of the input voltage in the totem PFC circuit, the working sample value and the zero-current reference value need to be processed accordingly based on the polarity signal POL of the input voltage. In some embodiments of this application, the polarity signal POL is determined by the control system based on the input voltage V. AC Real-time value generation, when the input voltage V AC When the input voltage VAC is greater than zero, the POL signal is 1; when the input voltage VAC is less than zero, the POL signal is 0.

[0055] When the polarity signal POL indicates that the input voltage is positive, i.e., POL=1, the inductor current flows into the Hall sensor from the IP+ terminal and out from the IP- terminal. At this time, the current conditioning signal is equal to the working sample value minus the zero current reference value, i.e., I0. adjust =I sample - I zero .

[0056] Specifically, when the polarity signal POL indicates that the input voltage is negative, i.e., POL=0, the inductor current flows into the Hall sensor from the IP- terminal and out from the IP+ terminal, with the current direction opposite to the positive half-cycle. At this time, the current conditioning signal is equal to the zero current reference value minus the working sampling value, i.e., I0. adjust = I ze ro - I sample This removes the zero-current bias and, through an inversion operation, obtains a positive signal that reflects the true magnitude of the inductor current.

[0057] Through the above differential operation processing based on polarity signals, the current conditioning signal I... adjust Always positive, accurately representing the inductor current i L The absolute value of the signal eliminates the influence of current direction changes on the control system. Specifically, the current conditioning signal I... adjust It can be directly used for the current loop closed-loop control of the Totem PFC circuit system to achieve precise adjustment of the inductor current, thereby achieving the purpose of power factor correction and output voltage stabilization control.

[0058] In some embodiments of this application, in order to prevent abnormal sampling from causing system malfunctions, a step of limiting the zero-current reference filter value is also included, specifically including the following steps: Step S610: Set the maximum correction amount Specifically, at the initial zero current reference value I zero_initial Based on this, set the maximum correction amount I limit It is easy to understand that the maximum correction amount is used to limit the adjustment range of the zero-current reference value, preventing the zero-current reference value from deviating too much from the normal range due to sampling abnormalities or Hall sensor malfunctions. In some embodiments of this application, the maximum correction amount I... limit The settings need to take into account the normal operating range of the Hall sensor, the fluctuation range of the power supply voltage, and the control accuracy requirements of the system.

[0059] As an example, and not a limitation, the maximum correction amount I limit The maximum correction value is typically set between 5% and 20% of the initial zero-current reference value. The specific value can be adjusted according to the characteristics of the Hall sensor and the system requirements in the actual application. Specifically, if the system requires high zero-point stability, a smaller maximum correction value can be set; if the system needs to adapt to large environmental changes, a larger maximum correction value can be set.

[0060] Step S620: When the zero current reference filter value is greater than the sum of the initial zero current reference value and the maximum correction amount, the zero current reference filter value is limited to the sum of the initial zero current reference value and the maximum correction amount.

[0061] In some embodiments of this application, when the zero-current reference filter value I zero_filter When the value exceeds the preset limit, it is subjected to amplitude limiting. Specifically, when the zero-current reference filter value is greater than the sum of the initial zero-current reference value and the maximum correction amount, i.e., I... zero_filter >I zero_initial + I limit At that time, the zero-current reference filter value is limited to the sum of the initial zero-current reference value and the maximum correction amount, i.e., I. zero_filter = I zero_initial + I limit .

[0062] Step S630: When the zero current reference filter value is less than the difference between the initial zero current reference value and the maximum correction amount, the zero current reference filter value is limited to the difference between the initial zero current reference value and the maximum correction amount.

[0063] In some embodiments of this application, when the zero-current reference filter value is less than the difference between the initial zero-current reference value and the maximum correction amount, i.e., I zero_filter zero_initial - I limit ​At that time, the zero-current reference filter value is limited to the difference between the initial zero-current reference value and the maximum correction amount, i.e., I. zero_filter = I zero_initial - I limit .

[0064] The aforementioned limiting process ensures that the zero-current reference value remains within a reasonable range, preventing system control failures caused by abnormal sampling values. Specifically, the limiting logic can be executed immediately after each zero-current reference filter value update, or it can be executed periodically to ensure the reliability of the zero-current reference value. In some embodiments of this application, the zero-current reference filter value after limiting is used as the final zero-current reference value I. zero Used for subsequent current conditioning calculations.

[0065] It is easy to understand that when the limiting process is triggered, it indicates an abnormal shift in the zero-current reference value. This could be due to factors such as malfunction of the Hall sensor, abnormal fluctuations in the power supply voltage, or a fault in the sampling circuit. In some embodiments of this application, when the triggering of the limiting process is detected, corresponding protection operations are performed on the Totem PFC circuit to prevent further damage or malfunction of the system.

[0066] Specifically, protection operations include stopping the PWM drive and / or system shutdown. By way of example and not limitation, stopping the PWM drive means that the control system stops sending pulse width modulation signals to switching transistors Q1 and Q2, causing the Totem PFC circuit to stop switching and enter a safe state. In some embodiments of this application, system shutdown means that the control system shuts down the entire Totem PFC circuit, cutting off the power supply to the main circuit and ensuring the system is in a completely safe state.

[0067] It is easy to understand that different threshold conditions can be set for triggering the protection operation. Specifically, the protection operation can be set to only be executed when the limiting process is triggered continuously more than a certain number of times within a preset time, in order to avoid false protection caused by occasional anomalies. In some embodiments of this application, the level of protection operation can also be set, for example, only stopping the PWM drive when an anomaly is detected for the first time, and performing a system shutdown operation if the anomaly persists.

[0068] As an example, and not a limitation, the execution of protection operations can also be accompanied by the output of alarm signals, such as sending fault information to external systems via LED indicators, buzzers, or communication interfaces, to facilitate timely fault detection and handling by maintenance personnel. Specifically, after the protection operation is executed, the system can record the time of the fault occurrence, the fault type, and related sampling data, providing a basis for subsequent fault analysis and system optimization.

[0069] Unlike existing technologies, the embodiments of the present invention obtain accurate zero-current reference values ​​indirectly by using a Hall sensor without a zero-current reference, thereby achieving current sampling, reducing the number of analog-to-digital converters used, lowering circuit costs, and reducing design complexity.

[0070] The present invention also provides an electronic device based on the above-described current sampling method for the totem PFC circuit, the schematic diagram of which is shown below. Figure 13 As shown, the electronic device 100 includes: One or more processors 101, a network interface 102, and a memory 103, Figure 13 The example consists of a processor 101, a network interface 102, and a memory 103.

[0071] The network interface 102 is communicatively connected to the corresponding processor 101, and the processor 101 and the memory 103 can be connected via a bus or other means. Figure 13 Taking the example of a connection between China and Israel via a bus.

[0072] The network interface 102 is used to establish communication connections between the processor 101 and other external devices, including the following types: RJ-45 interface, SC fiber optic interface, AUI interface, FDDI interface and Console interface.

[0073] The memory 103, as a non-volatile computer-readable storage medium, can be used to store non-volatile software programs, non-volatile computer-executable programs, and modules. The processor 101 executes various functional applications and data processing of the electronic device by running the non-volatile software programs, instructions, and units stored in the memory 103, thereby implementing the current sampling method of the totem PFC circuit in the above method embodiment.

[0074] The memory 103 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created based on the use of the electronic device. Furthermore, the memory 103 may include high-speed random access memory and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other non-volatile solid-state storage device. In some embodiments, the memory 103 may optionally include memory remotely located relative to the processor 101, and these remote memories can be connected to the electronic device via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0075] The one or more units are stored in the memory 103, and when executed by one or more processors 101, they execute the current sampling method of the totem PFC circuit in any of the above method embodiments.

[0076] The aforementioned electronic device can execute the current sampling method of the totem PFC circuit provided in the embodiments of the present invention, and has the corresponding program modules and beneficial effects for executing the method. Technical details not described in detail in the electronic device embodiments can be found in the current sampling method of the totem PFC circuit provided in the embodiments of the present invention.

[0077] This invention also provides a non-volatile computer-readable storage medium, which may be included in the device described in the above embodiments; or it may exist independently and not assembled into the device. The non-volatile computer-readable storage medium carries one or more programs, which, when executed, implement the current sampling method of the totem PFC circuit according to the embodiments of this disclosure.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them; under the concept of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of this application as described above. For the sake of brevity, they are not provided in detail; although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A current sampling method for a totem PFC circuit, the totem PFC circuit comprising an analog-to-digital converter and a Hall sensor, characterized in that, include: Set the initial zero current reference value; During the non-PWM drive phase of the totem PFC circuit, the output voltage of the Hall sensor is sampled by the analog-to-digital converter to obtain the sampled value; Adjust the zero current reference value based on the sampled value; During the PWM drive phase of the totem PFC circuit, the output voltage of the Hall sensor is sampled by the analog-to-digital converter to obtain the working sample value; Based on the polarity signal of the input voltage of the totem PFC circuit, a current conditioning signal is obtained based on the working sample value and the zero current reference value.

2. The method according to claim 1, characterized in that, The initial zero current reference value is set according to the power supply voltage of the Hall sensor; The initial zero-current reference value corresponds to the digital value of the output voltage of the Hall sensor in the zero-current state after being sampled by the analog-to-digital converter.

3. The method according to claim 1, characterized in that, The non-PWM drive phase includes the startup detection phase and / or zero-crossing commutation phase of the totem PFC circuit. During the startup detection phase, when the output voltage of the totem PFC circuit is greater than the input voltage, the output voltage of the Hall sensor is sampled by the analog-to-digital converter. During the zero-crossing commutation phase, when it is determined that the totem PFC circuit is in the zero-crossing commutation range of the input voltage, the output voltage of the Hall sensor is sampled by the analog-to-digital converter.

4. The method according to claim 1, characterized in that, The adjustment of the zero-current reference value based on the sampled value includes: Set the zero-current reference filter value, the first filter coefficient k1, and the second filter coefficient k2, where k2 = 1 - k1; According to the formula: Zero current reference filter value = k1 × Zero current reference filter value + k2 × Sample value, update the zero current reference filter value; Set the zero current reference value as the zero current reference filter value.

5. The method according to claim 1, characterized in that, The step of obtaining a current conditioning signal based on the polarity signal of the input voltage of the totem PFC circuit, and based on the working sample value and the zero current reference value, includes: When the polarity signal indicates that the input voltage is positive, the current conditioning signal is equal to the working sample value minus the zero current reference value; When the polarity signal indicates that the input voltage is negative, the current conditioning signal is equal to the zero current reference value minus the working sample value.

6. The method according to claim 1, characterized in that, It also includes limiting the zero-current reference filter value, including the following steps: Set the maximum correction amount; When the zero-current reference filter value is greater than the sum of the initial zero-current reference value and the maximum correction amount, the zero-current reference filter value is limited to the sum of the initial zero-current reference value and the maximum correction amount; When the zero-current reference filter value is less than the difference between the initial zero-current reference value and the maximum correction amount, the zero-current reference filter value is limited to the difference between the initial zero-current reference value and the maximum correction amount.

7. The method according to claim 6, characterized in that, When the limiting process is triggered, a protection operation is performed on the totem PFC circuit, which includes stopping the PWM drive and / or shutting down the system.

8. The method according to any one of claims 1-7, characterized in that, The Hall sensor is a Hall sensor without a zero-current reference.

9. An electronic device, characterized in that, include: At least one processor; At least one network interface, which is communicatively connected to a corresponding processor; as well as, A memory communicatively connected to the at least one processor; wherein, The network interface is used to establish communication connections between the processor and other external devices; The memory stores instructions that can be executed by the at least one processor, which, when executed by the at least one processor, enables the at least one processor to perform the current sampling method of the totem PFC circuit as described in any one of claims 1-8.

10. A non-volatile computer storage medium, characterized in that, The computer storage medium stores computer-executable instructions, which are executed by one or more processors to cause the one or more processors to perform the current sampling method of the totem PFC circuit as described in any one of claims 1-8.

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