Totem pole PFC system control method, apparatus and device, and storage medium

Abstract

The invention discloses a totem-pole PFC system control method, device and equipment and a storage medium, and the method determines a spread spectrum pulse width modulation switching frequency function based on the operation index of a totem-pole PFC system. And according to the switching frequency function and the power grid voltage angle at the current moment, determining a time sequence control parameter of spread spectrum pulse width modulation at the next moment. According to the time sequence control parameter of spread spectrum pulse width modulation at the next moment and the power grid voltage angle at the next moment, a modulation wave of a spread spectrum pulse width modulation signal is compensated and generated, and a switching device of the totem-pole PFC system is controlled, so that spread spectrum pulse width modulation of the totem-pole PFC system is realized; according to the control method, the frequency at each moment is determined based on the operation index of the system, and the frequency is controllable and highly meets the performance requirements of the system in all aspects. And on the other hand, the electromagnetic radiation emission value in the totem pole PFC system can be suppressed through a spread spectrum pulse width modulation mode, and the electromagnetic compatibility friendliness of the system is improved.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and in particular to a control method, device, equipment and storage medium of a totem pole PFC system. Background Art

[0002] With the widespread application of power electronic equipment, improving power factor has become an important research direction. Totem pole power factor correction (PFC) technology can solve the problem of low power factor of traditional rectifier circuits by controlling the waveform of input current to track the waveform of input voltage, so that the power factor is close to 1. This is of great significance for improving the energy utilization efficiency of the power grid and reducing the burden on the power grid.

[0003] The switching action of power electronic devices will produce instantaneous changes in voltage (also called dv / dt) and current (also called di / dt), which will in turn generate energy emitted to the outside, known as electromagnetic interference (EMI). In an environment where electronic equipment is increasingly dense, electromagnetic compatibility (EMC) has become an increasingly important consideration in PFC system design. The traditional totem pole PFC system uses a fixed-cycle control software phase-locked loop for angle compensation, and the system has poor electromagnetic compatibility, resulting in system stability that is increasingly unable to meet user needs. Summary of the invention

[0004] The present invention provides a control method, device, equipment and storage medium of a totem pole PFC system to suppress the radiation emission value in the totem pole PFC system and improve the electromagnetic compatibility friendliness of the system.

[0005] According to one aspect of the present invention, a control method for a totem pole PFC system is provided, the method comprising:

[0006] Determining a switching frequency function of spread spectrum pulse width modulation based on the operating index of the totem pole PFC system;

[0007] Determine the timing control parameters of the spread spectrum pulse width modulation at the next moment according to the switching frequency function and the grid voltage angle at the current moment;

[0008] According to the timing control parameters of the spread spectrum pulse width modulation at the next moment and the grid voltage angle at the next moment, the modulation wave of the spread spectrum pulse width modulation signal is compensated and generated, and the switch device of the totem pole PFC system is controlled.

[0009] Optionally, the operating indicators of the totem pole PFC system include basic characteristics of the switching device, system thermal efficiency requirements, system stability requirements, electromagnetic interference requirements, grid ripple requirements and grid harmonic standards;

[0010] The step of determining a switching frequency function of spread spectrum pulse width modulation based on an operating indicator of the totem pole PFC system includes:

[0011] Determining an upper limit value of the switching frequency of spread spectrum pulse width modulation according to the basic characteristics of the switching device and / or system thermal efficiency requirements;

[0012] Determine a lower limit value of the switching frequency of spread spectrum pulse width modulation according to at least one of the system stability requirement, the electromagnetic interference requirement, the grid ripple requirement and the grid harmonic standard;

[0013] Determine a probability density distribution function of a switching frequency of spread spectrum pulse width modulation according to the switching frequency upper limit value and the switching frequency lower limit value;

[0014] The switching frequency function of spread spectrum pulse width modulation is determined in combination with the switching frequency probability density distribution function, the switching frequency upper limit value and the switching frequency lower limit value.

[0015] Optionally, the determining the switching frequency function of spread spectrum pulse width modulation by combining the switching frequency probability density distribution function, the switching frequency upper limit value and the switching frequency lower limit value includes:

[0016] Determine the switching frequency function of spread spectrum pulse width modulation in a quarter of the power frequency period interval in combination with the switching frequency probability density distribution function, the switching frequency upper limit value and the switching frequency lower limit value;

[0017] According to the symmetry of the sine wave, the switching frequency function of the spread spectrum pulse width modulation in the interval of one quarter of the power frequency cycle is extended to the entire power frequency cycle.

[0018] Optionally, the timing control parameters include a maximum count value and a control period;

[0019] The step of determining the timing control parameters of the spread spectrum pulse width modulation at the next moment according to the switching frequency function and the grid voltage angle at the current moment includes:

[0020] Calculate the switching frequency of the spread spectrum pulse width modulation at the next moment according to the switching frequency function combined with the grid voltage angle at the current moment;

[0021] The maximum count value and the control period of the spread spectrum pulse width modulation at the next moment are determined according to the switching frequency of the spread spectrum pulse width modulation at the next moment.

[0022] Optionally, before calculating the switching frequency of spread spectrum pulse width modulation at a next moment according to the switching frequency function combined with the grid voltage angle at a current moment, the method further includes:

[0023] The switching frequency function is optimized using an engineering discretization method.

[0024] Optionally, generating a modulation wave of the spread spectrum pulse width modulation signal and controlling a switch device of the totem pole PFC system according to a timing control parameter of the spread spectrum pulse width modulation at the next moment includes:

[0025] Determining the total delay of the totem pole PFC system at the next moment according to the timing control parameters of the spread spectrum pulse width modulation at the next moment;

[0026] The total delay of the totem pole PFC system at the next moment is converted into a corresponding compensation angle by using a phase-locked loop;

[0027] The compensation angle is added to the calculated value of the grid voltage angle at the next moment to determine the target grid voltage angle at the next moment;

[0028] Generate a modulation wave of spread spectrum pulse width modulation according to a joint calculation result of the target grid voltage angle and an output signal of a control loop in the totem pole PFC system;

[0029] The switching device of the totem pole PFC system is controlled according to the modulation wave and the maximum count value.

[0030] Optionally, controlling a switch device of the totem pole PFC system according to the modulation wave and the maximum count value includes:

[0031] At the time of updating the maximum count value, writing the maximum count value into the carrier counter;

[0032] After a single write, the carrier counter is controlled to perform a count-down operation according to the system main frequency;

[0033] When the carrier counter counts to 0, the current moment ends and enters the next moment;

[0034] rewriting the maximum count value updated at this time into the carrier counter;

[0035] When the instantaneous value of the modulation wave is greater than the count value of the carrier counter, controlling the fourth switch device in the totem pole PFC system to be turned off and the third switch device to be turned on;

[0036] When the instantaneous value of the modulation wave is less than the count value of the carrier counter, the fourth switching device in the totem pole PFC system is controlled to be turned on and the third switching device is controlled to be turned off.

[0037] According to another aspect of the present invention, a control device for a totem pole PFC system is provided, the device comprising:

[0038] A switching frequency function determination module, used to determine a switching frequency function of spread spectrum pulse width modulation based on an operating index of the totem pole PFC system;

[0039] A timing control parameter determination module, used to determine the timing control parameters of the spread spectrum pulse width modulation at the next moment according to the switching frequency function and the grid voltage angle at the current moment;

[0040] The modulation module is used to generate a modulation wave of the spread spectrum pulse width modulation signal and control the switch device of the totem pole PFC system according to the timing control parameters of the spread spectrum pulse width modulation at the next moment.

[0041] According to another aspect of the present invention, an electronic device is provided, the electronic device comprising:

[0042] at least one processor; and

[0043] a memory communicatively connected to the at least one processor; wherein,

[0044] The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the totem pole PFC control method described in any embodiment of the present invention.

[0045] According to another aspect of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the totem pole PFC control method described in any embodiment of the present invention when executed.

[0046] The control method, device, equipment and storage medium of the totem pole PFC system provided in this embodiment determine the switching frequency function of the spread spectrum pulse width modulation based on the operating index of the totem pole PFC system. According to the switching frequency function and the grid voltage angle at the current moment, the timing control parameters of the spread spectrum pulse width modulation at the next moment are determined. According to the timing control parameters of the spread spectrum pulse width modulation at the next moment and the grid voltage angle at the next moment, the modulation wave of the spread spectrum pulse width modulation signal is compensated and generated, and the switch device of the totem pole PFC system is controlled, so as to realize the spread spectrum pulse width modulation of the totem pole PFC system. On the one hand, the frequency at each moment in the control method is determined based on the operating index of the system, and the frequency is controllable and highly consistent with the various performance requirements of the system. On the other hand, by means of spread spectrum pulse width modulation, the electromagnetic radiation emission value in the totem pole PFC system can be suppressed, and the electromagnetic compatibility friendliness of the system can be improved.

[0047] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0049] Figure 1 A circuit diagram of a totem pole PFC system provided by an embodiment of the present invention;

[0050] Figure 2 A schematic flow chart of a control method of a totem pole PFC system provided by an embodiment of the present invention;

[0051] Figure 3 A schematic flow chart of another control method of a totem pole PFC system proposed in an embodiment of the present invention;

[0052] Figure 4 A schematic diagram of waveforms of switching frequency and grid voltage in a totem pole PFC system provided by an embodiment of the present invention;

[0053] Figure 5 A schematic diagram of the control system composition of a totem pole PFC system provided by an embodiment of the present invention;

[0054] Figure 6 A method for generating a modulation wave and controlling a switch device provided in an embodiment of the present invention;

[0055] Figure 7 A schematic diagram of the composition of a control device of a totem pole PFC system provided by an embodiment of the present invention;

[0056] Figure 8 A schematic diagram of the structure of an electronic device that can be used to implement an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0057] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0058] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0059] In order to solve the problem mentioned in the background technology, an embodiment of the present invention provides a control method of a totem pole PFC system. Figure 1 A circuit diagram of a totem pole PFC system provided by an embodiment of the present invention, Figure 2 A flow chart of a control method of a totem pole PFC system provided by an embodiment of the present invention, combined with Figure 1 and Figure 2 , a control method of a totem pole PFC system, comprising:

[0060] S201. Determine a switching frequency function of spread spectrum pulse width modulation based on an operating index of a totem pole PFC system.

[0061] Specifically, the operating index of the totem pole PFC system refers to the basic parameters of the devices related to the operating state of the totem PFC system and the indexes that the system needs to achieve in various aspects of performance. For example, the operating index of the totem pole PFC system may include the characteristics of the switching devices of the system, the thermal efficiency requirements of the system, the stability requirements of the system, the EMI requirements of the system, the ripple requirements of the corresponding power grid of the system, and the harmonic requirements of the corresponding power grid of the system. The right branch 101 in the totem pole PFC system is also called the slow bridge arm. The slow bridge arm adopts a half-bridge configuration, and the first switch device S1 and the second switch device S2 thereon are controlled to switch at the power grid frequency to provide line rectification for the AC signal. The left branch 102 is a fast bridge arm, and the third switch device S3 and the fourth switch device S4 thereon are controlled to switch at a high frequency to increase the voltage and adjust the input current.

[0062] In traditional pulse width modulation control, the switching frequency of the switching device is fixed. Unlike the traditional pulse width modulation control with a fixed switching frequency, the spread spectrum pulse width modulation technology in the control method of the totem pole PFC system mentioned in the present application disperses the energy originally concentrated at the fixed frequency into a wider frequency range by making the switching frequency of the pulse width modulation signal change within a certain range, thereby reducing the electromagnetic interference in the totem pole PFC system to improve the system performance. In other words, the switching frequency of the spread spectrum pulse width modulation is not a constant, but dynamically changes according to a specific functional relationship within a certain frequency range. This functional relationship is also the switching frequency function, which can describe the changing law of the switching frequency of the pulse width modulation signal. Exemplarily, the switching frequency function can be a relationship function of the switching frequency of the pulse width modulation signal changing with time or the grid voltage angle. In the totem pole PFC system, spread spectrum pulse width modulation control can be introduced to at least the third switching device and the fourth switching device in the fast bridge arm.

[0063] According to the operating indicators of the totem pole PFC system, the reliable distribution range of the switching frequency in the spread spectrum pulse width modulation can be determined, that is, the distribution range of the switching frequency allowed by the system and the power grid. Furthermore, according to the distribution range, the switching frequency function of the spread spectrum pulse width modulation can be determined by formula fitting and other methods.

[0064] S202: Determine the timing control parameters of the spread spectrum pulse width modulation at the next moment according to the switching frequency function and the grid voltage angle at the current moment.

[0065] Specifically, the timing control parameters refer to parameters related to timing control such as pulse counting and cycle switching in spread spectrum pulse width modulation. For example, the timing control parameters include the maximum count value and the control cycle. According to the switching frequency function and the grid voltage angle at the current moment, the switching frequency of the spread spectrum pulse width modulation at the next moment can be determined. Based on the switching frequency of the spread spectrum pulse width modulation at the next moment, the timing control parameters of the spread spectrum pulse width modulation at the next moment can be determined. If the switching frequency is different, the interval lengths of adjacent moments are different.

[0066] S203, according to the timing control parameters of the spread spectrum pulse width modulation at the next moment and the grid voltage angle at the next moment, compensate and generate the modulation wave of the spread spectrum pulse width modulation and control the switch devices of the totem pole PFC system.

[0067] Specifically, based on the timing control parameters of the spread spectrum pulse width modulation at the next moment, the total system delay at the next moment can be determined. Using the software phase-locked loop in the totem pole PFC system, the total system delay at the next moment can be converted into a corresponding delay angle (or compensation angle). According to the delay angle and the grid voltage angle determined by the software phase-locked loop, the target voltage angle of the control process at the next moment can be determined, that is, the grid voltage angle that the control process at the next moment needs to achieve. According to the grid voltage angle, the modulation wave at the next moment can be generated accordingly, thereby controlling the switching devices in the totem pole PFC.

[0068] The control method of the totem pole PFC system provided in this embodiment determines the switching frequency function of the spread spectrum pulse width modulation based on the operating index of the totem pole PFC system. According to the switching frequency function and the grid voltage angle at the current moment, the timing control parameters of the spread spectrum pulse width modulation at the next moment are determined. According to the timing control parameters of the spread spectrum pulse width modulation at the next moment, the modulation wave of the spread spectrum pulse width modulation signal is generated and the switch device of the totem pole PFC system is controlled, so as to realize the spread spectrum pulse width modulation of the switch device in the totem pole PFC. On the one hand, the frequency at each moment in the control method is determined based on the operating index of the system, and the frequency is controllable and highly consistent with the various performance requirements of the system. On the other hand, by means of spread spectrum pulse width modulation, the electromagnetic radiation emission value in the totem pole PFC system can be suppressed, and the electromagnetic compatibility friendliness of the system can be improved.

[0069] Figure 3 This is a flow chart of another control method of a totem pole PFC system proposed in an embodiment of the present invention, referring to Figure 3 , a control method of a totem pole PFC system, comprising:

[0070] S301. Determine a probability density distribution function of a switching frequency of spread spectrum pulse width modulation based on an operating index of a totem pole PFC system.

[0071] Specifically, the operating indicators of the totem pole PFC system include basic characteristics of switching devices, system thermal efficiency requirements, system stability requirements, electromagnetic interference requirements, grid ripple requirements and grid harmonic standards.

[0072] Determine the probability density distribution function of the switching frequency of the spread spectrum pulse width modulation. On the one hand, it is necessary to determine the upper limit value f of the switching frequency of the spread spectrum pulse width modulation according to the basic characteristics of the switching device and / or the system thermal efficiency requirements. max. Exemplarily, the basic characteristics of the switching device may include characteristic parameters such as the on-resistance, switching speed, maximum rated voltage, maximum rated current, parasitic capacitance and parasitic inductance of the switching device that may affect the switching loss and conduction loss of the switching device; the system thermal efficiency requirement is a preset percentage, which can be set accordingly according to the system application requirements. For example, the system thermal efficiency requirement may be 95%. To determine the upper limit of the switching frequency, the switching loss and conduction loss of the switching device may be calculated based on the characteristics of the switching device. The total power loss range may be determined based on the total loss allowed by the system and the thermal efficiency requirements of the system. By adjusting the switching frequency and balancing the switching loss and conduction loss, the switching frequency range that meets the thermal efficiency requirements of the system is determined, and then the base switching frequency value f of the spread spectrum pulse width modulation is determined. base , which is the upper limit of the switching frequency f max .

[0073] On the other hand, the switching frequency lower limit value f of the spread spectrum pulse width modulation can be determined according to at least one of the system stability requirement, the electromagnetic interference requirement, the grid ripple requirement and the grid harmonic standard. min, for example: 1. In terms of system stability, on the one hand, analyze the loop characteristics of the system, which include the bandwidth and phase margin of the control loop. A higher switching frequency helps to improve the response speed of the system, but too high a switching frequency may cause system instability. On the other hand, analyze the impact of the switching frequency on the position of the poles and zeros of the system. A lower switching frequency may make the low-frequency poles and zeros of the system closer to the imaginary axis, affecting the stability of the system. For example, by establishing a small signal model of the system, control theory (such as Bode plot analysis and root locus analysis) can be used to evaluate the stability of the system at different switching frequencies, and finally determine the lower limit of the switching frequency corresponding to the system stability requirements. 2. In terms of electromagnetic interference, a lower switching frequency may lead to stronger low-frequency electromagnetic interference, because the switching frequency and its harmonics are more likely to fall in the low-frequency band, and low-frequency electromagnetic interference is more difficult to eliminate by filtering means. Then, when determining the lower limit of the switching frequency, it should be ensured that the low-frequency part after spectrum expansion will not cause the electromagnetic interference to exceed the limit specified by the standard. For example, the electromagnetic interference spectrum distribution under different switching frequencies can be analyzed by electromagnetic interference simulation software or actual measurement equipment; and then ensure that the minimum operating frequency of the totem pole PFC system after spectrum expansion meets the limit of electromagnetic interference related standards (such as CISPR 22), and determine the lower limit of the switching frequency corresponding to the system electromagnetic interference requirements. 3. In terms of grid ripple, the switching frequency will affect the frequency and amplitude of the output ripple. A higher switching frequency will increase the ripple frequency, and the ripple amplitude will decrease under the same output capacitance. Then, according to the grid voltage formula, the required minimum switching frequency can be calculated, that is, the lower limit of the switching frequency corresponding to the grid ripple requirements. 4. In terms of grid harmonics, the switching frequency affects the harmonic characteristics of the input current. A lower switching frequency may cause the input current to contain more low-frequency harmonic components, affecting the power factor and grid quality. Therefore, by referring to relevant grid standards (such as IEEE 519), the allowable harmonic content can be determined, and the lower limit of the switching frequency corresponding to the grid harmonic standard can be determined based on this. In summary, in order to meet multiple requirements at the same time, this application can take the maximum value of the lower limits corresponding to multiple requirements as the lower limit of the switching frequency of spread spectrum pulse width modulation.

[0074] Combining the two aspects, according to the upper limit value of the switching frequency and the lower limit value of the switching frequency, the probability density distribution function of the switching frequency of the spread spectrum pulse width modulation can be determined. The probability density distribution function of the switching frequency describes the probability density of the switching frequency near different values. For example, if the value of the probability density distribution function at a certain frequency is large, it means that in the actual system, the probability of the switching frequency of the spread spectrum pulse width modulation being close to this frequency is relatively high; and if the probability density is zero in a certain frequency interval, it means that the switching frequency is almost impossible to appear in this interval. Exemplarily, the probability density distribution function of the switching frequency of the spread spectrum pulse width modulation can be expressed as the first formula in, is the switching frequency function of the spread spectrum pulse width modulation, which varies with the grid voltage angle change.

[0075] S302 , determining a switching frequency function of spread spectrum pulse width modulation in combination with a switching frequency probability density distribution function, a switching frequency upper limit value, and a switching frequency lower limit value.

[0076] Specifically, once the upper limit value of the switching frequency of the spread spectrum pulse width modulation is max and the switching frequency lower limit f min The probability density distribution function of its switching frequency is fixed. According to the switching frequency distribution density function of the spread spectrum pulse width modulation, the upper limit value of the switching frequency of the spread spectrum pulse width modulation, the lower limit value of the switching frequency and the grid voltage angle, the switching frequency function of the spread spectrum pulse width modulation in the quarter power frequency period interval can be determined. The analytical expression can be expressed as the second formula Here, ln represents the logarithmic calculation with the base being the natural constant e. Figure 4 A waveform diagram of a switching frequency and a grid voltage in a totem pole PFC system provided by an embodiment of the present invention, referring to Figure 4 , the boundary condition in the quarter power frequency period interval [0, π / 2] in the second formula can be expressed by the third formula as According to the symmetry of the sine wave, the switching frequency function of the spread spectrum pulse width modulation in the quarter power frequency period interval is extended to the entire power frequency period [0, 2π], and the fourth formula is obtained:

[0077] S303: Optimize the switching frequency function using an engineering discretization method.

[0078] Specifically, in order to facilitate the implementation of the totem pole PFC control method proposed in this application in engineering software, the right side of the second formula can be expanded and the high-order terms can be ignored to determine the fifth formula: Among them, the higher-order terms may include second-order or higher-order terms.

[0079] In addition, if you want to further save the computing power resources of the chip, you can also calculate the logarithmic terms in the fifth formula offline and solidify them into the storage unit as constants, thereby simplifying the fifth formula to the sixth formula: in, B=1+ln(f max ), both are fixed parameters of offline calculation; k represents the current moment, k+1 represents the next moment, is the grid voltage angle at the current moment, is the switching frequency of the spread spectrum pulse width modulation at the next moment.

[0080] S304: Determine the maximum count value and control period of the spread spectrum pulse width modulation at the next moment according to the switching frequency function and the grid voltage angle at the current moment.

[0081] Specifically, the switching frequency of the spread spectrum pulse width modulation at the next moment is calculated based on the switching frequency function combined with the grid voltage angle at the current moment. For example, the switching frequency of the spread spectrum pulse width modulation at the next moment can be determined by substituting the grid voltage angle at the current moment into the switching frequency function.

[0082] According to the switching frequency of the spread spectrum pulse width modulation at the next moment, the maximum count value and control period of the spread spectrum pulse width modulation at the next moment are determined. Exemplarily, the relationship between the maximum count value of the spread spectrum pulse width modulation at the next moment and the switching frequency of the spread spectrum pulse width modulation at the next moment can be expressed as the seventh formula: Among them, S1(k+1) represents the maximum count value of the spread spectrum pulse width modulation at the next moment, f(k+1) represents the output switching frequency of the spread spectrum pulse width modulation at the next moment, and K represents the main crystal oscillator frequency of the counter of the spread spectrum pulse width modulation in the system. It should be particularly noted that in the process of pulse width modulation of the switch device of the totem pole PFC system, at the beginning of each moment, the maximum count value S1(k) of the spread spectrum pulse width modulation updated at the current moment is written into the carrier counter, and the carrier counter is controlled by the timer to perform a count-down operation. The timer of the spread spectrum pulse width modulation subsystem (or spread spectrum pulse width modulation module) in the totem pole PFC system counts 1 time according to the main crystal oscillator frequency, and the carrier counter is reduced by 1. When the count value of the carrier counter reaches 0, the flag bit of the carrier counter of the spread spectrum pulse width modulation is triggered to flip. When the flag bit of the carrier counter of the spread spectrum pulse width modulation flips, the spread spectrum pulse width modulation updates the maximum count value S1(k+1) of the spread spectrum pulse width modulation at the next moment and assigns it to the carrier counter.

[0083] According to the switching frequency of the spread spectrum pulse width modulation at the next moment, the control period of the spread spectrum pulse width modulation at the next moment is determined. Exemplarily, the relationship between the control period at the next moment and the switching frequency of the spread spectrum pulse width modulation at the next moment can be expressed as the eighth formula: Among them, T ctr (k+1) represents the control period of the spread spectrum pulse width modulation at the next moment.

[0084] S305: Determine the target grid voltage angle at the next moment according to the control period of the spread spectrum pulse width modulation at the next moment.

[0085] Specifically, Figure 5 A schematic diagram of the control system composition of a totem pole PFC system provided by an embodiment of the present invention, referring to Figure 5The control system of the totem pole PFC system includes not only the spread spectrum pulse width modulation subsystem, but also the software phase-locked loop compensation subsystem (also called the software phase-locked loop compensation module). The target voltage angle refers to the grid voltage angle that the software phase-locked loop compensation module aims to achieve, and is also the grid voltage angle after compensation by the software phase-locked loop compensation module.

[0086] According to the timing control parameters of the spread spectrum pulse width modulation at the next moment, the total delay of the totem pole PFC system at the next moment can be determined. For example, according to the control period of the spread spectrum pulse width modulation at the next moment, combined with the ninth formula, the total delay of the control system at the next moment can be determined. The ninth formula can be expressed as T d (k+1)=T zoh (k+1)+T ctr (k+1)=0.5T sample (k+1)+T ctr (k+1), where T zoh (k+1) is the sampling delay time of the next moment, which can be equal to half of the sampling period; T ctr (k+1) is the control period at the next moment, T d (k+1) is the total delay from the sampling moment to the moment when the duty cycle is calculated and sent based on the sampling value at the next moment; T sample (k+1) is the sampling period of the next moment; control period T ctr (k+1) and sampling period T sample (k+1) has a constant proportional relationship, which depends on the number of sampling times in a single control cycle.

[0087] By using a phase-locked loop, the total delay of the totem pole PFC system at the next moment can be converted into a corresponding compensation angle. For example, the total delay of the control system at the next moment is calculated according to the control cycle of the spread spectrum pulse width modulation output at the next moment. Through the software phase-locked loop compensation module, the total delay of the control system at the next moment can be converted into a corresponding delay angle (or compensation angle) by using the tenth formula. The tenth formula can be expressed as in, is the compensation angle of the software phase-locked loop compensation module at the next moment, f c is the fundamental frequency of the totem pole PFC system.

[0088] The compensation angle is added to the calculated value of the grid voltage angle at the next moment to determine the target grid voltage angle at the next moment. For example, based on the eleventh formula, the compensation angle is superimposed on the grid voltage angle calculated by the software phase-locked loop compensation module. The eleventh formula can be expressed as in, is the target grid voltage angle of the software phase-locked loop compensation module at the next moment, It is the grid voltage angle calculated by the software phase-locked loop compensation module at the next moment.

[0089] S306 . Generate a modulation wave of spread spectrum pulse width modulation according to the target grid voltage angle and control the switch devices of the totem pole PFC system.

[0090] Specifically, a modulation wave of spread spectrum pulse width modulation is generated according to a joint calculation result of a target grid voltage angle and an output signal of a control loop in a totem pole PFC system.

[0091] According to the modulation wave and carrier count value, the switching devices of the totem pole PFC system are controlled. Figure 6 A method for generating a modulation wave and controlling a switch device provided in an embodiment of the present invention, combined with Figure 1 and Figure 6 , a modulation wave of spread spectrum pulse width modulation is generated according to the joint calculation result of the target grid voltage angle and the output signal of the control loop in the totem pole PFC system. The instantaneous value of the modulation wave of spread spectrum pulse width modulation is compared with the carrier count value of the carrier counter. When the instantaneous value of the modulation wave is greater than the carrier count value of the carrier counter, the third switch device S3 in the totem pole PFC system is controlled to be turned on and the fourth switch device S4 is turned off. When the instantaneous value of the modulation wave is less than the carrier count value of the carrier counter, the third switch device S3 in the totem pole PFC system is controlled to be turned off and the fourth switch device S4 is turned on.

[0092] Exemplarily, at the moment of updating the maximum count value, the maximum count value is written into the carrier counter; after a single write, the carrier counter is controlled to perform a count-down operation according to the system main frequency; when the carrier counter counts to 0, the current moment ends and enters the next moment. The updated maximum count value is rewritten into the carrier counter. When the instantaneous value of the modulation wave is greater than the carrier count value of the carrier counter, the fourth switch device in the totem pole PFC system is controlled to be turned off and the third switch device is turned on. When the instantaneous value of the modulation wave is less than the carrier count value of the carrier counter, the fourth switch device in the totem pole PFC system is controlled to be turned on and the third switch device is turned off. The relevant contents of generating the modulation wave of spread spectrum pulse width modulation and controlling the switch device in the totem pole PFC system have been described in detail in the inventor's prior patent (publication number CN117254681A), and will not be repeated here.

[0093] In the control method of the totem pole PFC system provided in this embodiment, the upper limit value of the switching frequency of the spread spectrum pulse width modulation is determined according to the basic characteristics of the switching device and / or the system thermal efficiency requirements. The lower limit value of the switching frequency of the spread spectrum pulse width modulation is determined according to at least one of the system stability requirements, the electromagnetic interference requirements, the grid ripple requirements and the grid harmonic standards. The probability density distribution function of the switching frequency of the spread spectrum pulse width modulation is determined according to the upper limit value of the switching frequency and the lower limit value of the switching frequency. The switching frequency function of the spread spectrum pulse width modulation is determined by combining the probability density distribution function of the switching frequency, the upper limit value of the switching frequency and the lower limit value of the switching frequency, so that the determination of the switching frequency function by multiple system operation indicators is realized. Such a setting method can make the frequency range of the spread spectrum pulse width modulation adapt to the various requirements of the system, and on the basis of ensuring other performance requirements of the system, the electromagnetic radiation emission value of the system is suppressed, and the electromagnetic compatibility friendliness of the system is improved.

[0094] An embodiment of the present invention further provides a control device for a totem pole PFC system. Figure 7 A schematic diagram of a control device for a totem pole PFC system provided by an embodiment of the present invention, referring to Figure 7 The control device 700 of the totem pole PFC system includes a switching frequency function determination module 701, a timing control parameter determination module 702 and a modulation module. The switching frequency function determination module 701 is used to determine the switching frequency function of the spread spectrum pulse width modulation based on the operation index of the totem pole PFC system. The timing control parameter determination module 702 is used to determine the timing control parameters of the spread spectrum pulse width modulation at the next moment according to the switching frequency function and the grid voltage angle at the current moment. The modulation module 703 is used to compensate and generate the modulation wave of the spread spectrum pulse width modulation signal and control the switch device of the totem pole PFC system according to the timing control parameters of the spread spectrum pulse width modulation at the next moment and the grid voltage angle at the next moment.

[0095] The control device of the totem pole PFC system provided in the embodiment of the present invention can execute the control method of the totem pole PFC system provided in any embodiment of the present invention, and has the functional modules and beneficial effects corresponding to the execution method.

[0096] Figure 8 A schematic diagram of an electronic device that can be used to implement an embodiment of the present invention is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device may also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices (such as helmets, glasses, watches, etc.) and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present invention described and / or required herein.

[0097] like Figure 8 As shown, the electronic device 10 includes at least one processor 11, and a memory connected to the at least one processor 11, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc., wherein the memory stores a computer program that can be executed by at least one processor, and the processor 11 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 12 or the computer program loaded from the storage unit 18 to the random access memory (RAM) 13. In the RAM 13, various programs and data required for the operation of the electronic device 10 can also be stored. The processor 11, the ROM 12, and the RAM 13 are connected to each other through a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0098] A number of components in the electronic device 10 are connected to the I / O interface 15, including: an input unit 16, such as a keyboard, a mouse, etc.; an output unit 17, such as various types of displays, speakers, etc.; a storage unit 18, such as a disk, an optical disk, etc.; and a communication unit 19, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 19 allows the electronic device 10 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0099] The processor 11 may be a variety of general and / or dedicated processing components with processing and computing capabilities. Some examples of the processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any appropriate processor, controller, microcontroller, etc. The processor 11 executes the various methods and processes described above, such as the control method of the totem pole PFC system.

[0100] In some embodiments, the control method of the totem pole PFC system may be implemented as a computer program, which is tangibly contained in a computer-readable storage medium, such as a storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or installed on the electronic device 10 via the ROM 12 and / or the communication unit 19. When the computer program is loaded into the RAM 13 and executed by the processor 11, one or more steps of the control method of the totem pole PFC system described above may be performed. Alternatively, in other embodiments, the processor 11 may be configured to execute the control method of the totem pole PFC system in any other appropriate manner (e.g., by means of firmware).

[0101] Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0102] Computer programs for implementing the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that when the computer program is executed by the processor, the functions / operations specified in the flow chart and / or block diagram are implemented. The computer program may be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.

[0103] In the context of the present invention, a computer-readable storage medium may be a tangible medium that may contain or store a computer program for use by or in combination with an instruction execution system, device or equipment. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or equipment, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0104] To provide interaction with a user, the systems and techniques described herein may be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and a pointing device (e.g., a mouse or trackball) through which the user can provide input to the electronic device. Other types of devices may also be used to provide interaction with the user; for example, the feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form (including acoustic input, voice input, or tactile input).

[0105] The systems and techniques described herein may be implemented in a computing system that includes backend components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes frontend components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0106] A computing system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The client and server relationship is generated by computer programs running on the corresponding computers and having a client-server relationship with each other. The server may be a cloud server, also known as a cloud computing server or cloud host, which is a host product in the cloud computing service system to solve the defects of difficult management and weak business scalability in traditional physical hosts and VPS services.

[0107] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0108] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A control method for a totem pole PFC system, characterized in that: include: Determining a switching frequency function of spread spectrum pulse width modulation based on the operating index of the totem pole PFC system; Determine the timing control parameters of the spread spectrum pulse width modulation at the next moment according to the switching frequency function and the grid voltage angle at the current moment; According to the timing control parameters of the spread spectrum pulse width modulation at the next moment and the grid voltage angle at the next moment, the modulation wave of the spread spectrum pulse width modulation signal is compensated and generated, and the switch device of the totem pole PFC system is controlled.

2. The method according to claim 1, characterized in that The operating indicators of the totem pole PFC system include the basic characteristics of the switching device, system thermal efficiency requirements, system stability requirements, electromagnetic interference requirements, grid ripple requirements and grid harmonic standards; The step of determining a switching frequency function of spread spectrum pulse width modulation based on an operating indicator of the totem pole PFC system includes: Determining an upper limit value of the switching frequency of spread spectrum pulse width modulation according to the basic characteristics of the switching device and / or system thermal efficiency requirements; Determine a lower limit value of the switching frequency of spread spectrum pulse width modulation according to at least one of the system stability requirement, the electromagnetic interference requirement, the grid ripple requirement and the grid harmonic standard; Determine a probability density distribution function of a switching frequency of spread spectrum pulse width modulation according to the switching frequency upper limit value and the switching frequency lower limit value; The switching frequency function of spread spectrum pulse width modulation is determined in combination with the switching frequency probability density distribution function, the switching frequency upper limit value and the switching frequency lower limit value.

3. The method according to claim 2, characterized in that The step of combining the switching frequency probability density distribution function, the switching frequency upper limit value, and the switching frequency lower limit value to determine the switching frequency function of spread spectrum pulse width modulation includes: Determine the switching frequency function of spread spectrum pulse width modulation in a quarter of the power frequency period interval in combination with the switching frequency probability density distribution function, the switching frequency upper limit value and the switching frequency lower limit value; According to the symmetry of the sine wave, the switching frequency function of the spread spectrum pulse width modulation in the interval of one quarter of the power frequency cycle is extended to the entire power frequency cycle.

4. The method according to claim 1, characterized in that: The timing control parameters include a maximum count value and a control period; The step of determining the timing control parameters of the spread spectrum pulse width modulation at the next moment according to the switching frequency function and the grid voltage angle at the current moment includes: Calculate the switching frequency of the spread spectrum pulse width modulation at the next moment according to the switching frequency function combined with the grid voltage angle at the current moment; The maximum count value and the control period of the spread spectrum pulse width modulation at the next moment are determined according to the switching frequency of the spread spectrum pulse width modulation at the next moment.

5. The method according to claim 4, characterized in that Before calculating the switching frequency of the spread spectrum pulse width modulation at the next moment according to the switching frequency function combined with the grid voltage angle at the current moment, the method further includes: The switching frequency function is optimized using an engineering discretization method.

6. The method according to claim 1, characterized in that The method of compensating and generating a modulation wave of the spread spectrum pulse width modulation signal and controlling the switch device of the totem pole PFC system according to the timing control parameters of the spread spectrum pulse width modulation at the next moment and the grid voltage angle at the next moment includes: Determining the total delay of the totem pole PFC system at the next moment according to the timing control parameters of the spread spectrum pulse width modulation at the next moment; The total delay of the totem pole PFC system at the next moment is converted into a corresponding compensation angle by using a phase-locked loop; The compensation angle is added to the calculated value of the grid voltage angle at the next moment to determine the target grid voltage angle at the next moment; Generate a modulation wave of spread spectrum pulse width modulation according to a joint calculation result of the target grid voltage angle and an output signal of a control loop in the totem pole PFC system; The switching device of the totem pole PFC system is controlled according to the modulation wave and the maximum count value.

7. The method according to claim 6, characterized in that The method of controlling the switch device of the totem pole PFC system according to the modulation wave and the maximum count value comprises: At the time of updating the maximum count value, writing the maximum count value into the carrier counter; After a single write, the carrier counter is controlled to perform a count-down operation according to the system main frequency; When the carrier counter counts to 0, the current moment ends and enters the next moment; rewriting the updated maximum count value into the carrier counter; When the instantaneous value of the modulation wave is greater than the count value of the carrier counter, controlling the fourth switch device in the totem pole PFC system to be turned off and the third switch device to be turned on; When the instantaneous value of the modulation wave is less than the count value of the carrier counter, the fourth switching device in the totem pole PFC system is controlled to be turned on and the third switching device is controlled to be turned off.

8. A control device for a totem pole PFC system, characterized in that: include: A switching frequency function determination module, used to determine a switching frequency function of spread spectrum pulse width modulation based on an operating index of the totem pole PFC system; A timing control parameter determination module, used to determine the timing control parameters of the spread spectrum pulse width modulation at the next moment according to the switching frequency function and the grid voltage angle at the current moment; The modulation module is used to generate a modulation wave of the spread spectrum pulse width modulation signal and control the switch device of the totem pole PFC system according to the timing control parameters of the spread spectrum pulse width modulation at the next moment.

9. An electronic device, characterized in that: The electronic device comprises: at least one processor; and a memory communicatively connected to the at least one processor; wherein, The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can perform the control method of the totem pole PFC system according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the control method of the totem pole PFC system according to any one of claims 1 to 7 when executed.

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