Pwm modulation method and pwm modulation apparatus

Abstract

The embodiment of the present application discloses a PWM modulation method and a PWM modulation device, which are used for PWM modulation in the case of reducing the possibility of abnormality of a PWM modulated signal. The method comprises: if a condition of triggering a target parameter being assigned a target parameter value is met, determining whether a current count value is in a preset unassignable region corresponding to a current mode, wherein the preset unassignable region is a count value near a preset loading point corresponding to the current mode; if the current count value is in the preset unassignable region, taking a count value after the current count value is extended for a preset count duration as a target assignment point, wherein the target assignment point is outside the preset unassignable region; assigning the target parameter to the target parameter value at the target assignment point, so that the target parameter value of the target parameter is obtained at the preset loading point, and a new PWM signal is generated based on the target parameter value of the target parameter.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the field of PWM modulation, and more particularly, to a PWM modulation method and a PWM modulation device. BACKGROUND

[0002] With the development of PWM modulation technology, PWM modulation devices are needed in many fields to perform fast frequency conversion or duty cycle operation. For example, a PWM modulation device can control the on and off operation of a circuit switching device by adjusting the frequency and duty cycle.

[0003] The existing PWM modulation method is that if a condition of assigning a target parameter to a target parameter value is triggered, the assignment can be performed at a fixed time point other than a preset loading point to assign the target parameter of a register to the target parameter value, and then the target parameter value of the target parameter is obtained from the register at the preset loading point, and a new PWM signal is generated based on the target parameter value of the target parameter.

[0004] However, this method only implements the assignment operation and does not consider the possibility of unreasonable time points of assignment, so the probability of missing the carrier zero-crossing point of the current cycle is large, and the possibility of abnormal waveform of the PWM modulated signal is large. SUMMARY

[0005] Embodiments of the present application provide a PWM modulation method and a PWM modulation device for performing PWM modulation while reducing the possibility of abnormality of the PWM modulated signal.

[0006] In a first aspect, embodiments of the present application provide a PWM modulation method, comprising:

[0007] If a condition of assigning a target parameter to a target parameter value is triggered, it is determined whether a current count value is within a preset non-assignable region corresponding to a current mode; wherein the preset non-assignable region is a count value near a preset loading point corresponding to the current mode;

[0008] If the current count value is within the preset non-assignable region, a count value after the current count value is extended by a preset count duration is taken as a target assignment point; wherein the target assignment point is outside the preset non-assignable region;

[0009] At the target assignment point, the target parameter is assigned to the target parameter value, so that the target parameter value of the target parameter is obtained at the preset loading point, and a new PWM signal is generated based on the target parameter value of the target parameter.

[0010] Optionally, before the current count value is assigned as the target assignment point after the current count value is prolonged for a preset count duration, the method further comprises:

[0011] predicting a first count duration consumed for performing the step of determining whether the current count value is in a preset unassignable region corresponding to the current mode;

[0012] predicting a second count duration consumed for performing the step of assigning the target parameter to the target parameter value at the target assignment point;

[0013] determining the preset count duration based on the first count duration and the second count duration.

[0014] Optionally, before the preset count duration is determined based on the first count duration and the second count duration, the method further comprises:

[0015] determining an adjustment count duration;

[0016] the preset count duration is determined based on the first count duration, the second count duration and the adjustment count duration.

[0017]

[0018] Optionally, the preset unassignable region is a count value range in a preset count duration range of the preset loading point; the current mode comprises a current loading mode and a current carrier mode; and the current carrier mode is an increasing-decreasing mode; and the preset loading point is a zero-crossing point of the carrier.

[0019] before the step of determining whether the current count value is in a preset unassignable region corresponding to the current mode, the method further comprises:

[0020] if the current loading mode is a shadow mode, for each falling edge of the carrier, a count value range between a target count value of the falling edge and the zero-crossing point is taken as the preset unassignable region; wherein the shadow mode represents loading at the preset loading point; and a count value difference between the target count value corresponding to the falling edge and the zero-crossing point is the preset count duration.

[0021] Optionally, the step of determining whether the current count value is in a preset unassignable region corresponding to the current mode comprises:

[0022] if the current count value is a count value of a falling edge of the carrier, and the current count value is included in a count value range corresponding to the preset unassignable region, it is determined that the current count value is in a preset unassignable region corresponding to the current mode. ​

[0023] Optionally, the preset non-assignable region is a counting value in a preset design time length range of the preset loading point; the current mode includes a current loading mode and a current carrier mode; and the current carrier mode is an increase / decrease mode.

[0024] Before the determining whether the current counting value is in the preset non-assignable region corresponding to the current mode, the method further includes:

[0025] If the current loading mode is an immediate mode, it is determined that the preset loading point corresponding to the current mode is a target loading point corresponding to the immediate mode; wherein the immediate mode represents that a current assignment point is taken as the target loading point, and loading is performed immediately at the target loading point; the current assignment point is any one counting value.

[0026] For a rising edge of a carrier, a counting value range between a first counting value of the rising edge and the target loading point is taken as a preset non-assignable region of the rising edge; wherein a counting value difference between the first counting value corresponding to the rising edge and the target loading point is the preset design time length.

[0027] For a falling edge of the carrier, a counting value range between a second counting value of the falling edge and the target loading point is taken as a preset non-assignable region of the falling edge; wherein a counting value difference between the second counting value corresponding to the falling edge and the target loading point is the preset design time length.

[0028] Optionally, the if the current counting value is in the preset non-assignable region includes at least one of the following conditions:

[0029] If the current counting value is a counting value of a rising edge of the carrier, and the current counting value is included in a counting value range corresponding to a preset non-assignable region of the rising edge, it is determined that the current counting value is in the preset non-assignable region.

[0030] If the current counting value is a counting value of a falling edge of the carrier, and the current counting value is included in a counting value range corresponding to a preset non-assignable region of the falling edge, it is determined that the current counting value is in the preset non-assignable region.

[0031] Optionally, after the determining whether the current counting value is in the preset non-assignable region corresponding to the current mode, before the assigning the target parameter to the target parameter value at the target assignment point, the method further includes:

[0032] If the current counting value is not in the preset non-assignable region, the current counting value is taken as the target assignment point.

[0033] In a second aspect, the embodiments of the present application provide a PWM modulation device, comprising:

[0034] A determination unit is configured to determine whether the current count value is in a preset non-assignable region corresponding to the current mode if a condition of triggering the target parameter to be assigned to the target parameter value is met, wherein the preset non-assignable region is a count value near a preset loading point corresponding to the current mode.

[0035] The determination unit is further configured to take a count value after the current count value is extended for a preset count duration as a target assignment point if the current count value is in the preset non-assignable region, wherein the target assignment point is outside the preset non-assignable region.

[0036] An assignment unit is configured to assign the target parameter to the target parameter value at the target assignment point, so that the target parameter value of the target parameter is obtained at the preset loading point, and a new PWM signal is generated based on the target parameter value of the target parameter.

[0037] In a third aspect, the embodiments of the present application provide a PWM modulation device, comprising:

[0038] A central processing unit, a memory, an input and output interface, and a power supply;

[0039] The memory is a transitory storage memory or a persistent storage memory;

[0040] The central processing unit is configured to communicate with the memory and execute instruction operations in the memory to perform the PWM modulation method.

[0041] In a fourth aspect, the embodiments of the present application provide a computer program product containing instructions, which, when the computer program product is run on a computer, causes the computer to execute the PWM modulation method.

[0042] From the above technical solution can be seen, the present application embodiment has the following advantages: can if trigger the target parameter is assigned to the target parameter value condition, determine whether the current count value is in the current mode corresponding to the preset non-assignable region, wherein the preset non-assignable region is in the current mode corresponding to the preset load point near the count value, if the current count value is in the preset non-assignable region, the count value after the current count value is extended by a preset count duration is used as the target assignment point, wherein the target assignment point is outside the preset non-assignable region, the target parameter is assigned to the target parameter value at the target assignment point, so that the target parameter value of the target parameter is obtained at the preset load point, and a new PWM signal is generated based on the target parameter value of the target parameter. It can be determined whether in the preset non-assignable region to determine a more reasonable assignment point to bypass the load point, the probability of missing the carrier zero crossing point of the current period is smaller, and the possibility of abnormal signal of PWM modulation is lower. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 A flowchart of a PWM modulation method disclosed by the embodiment of the present application;

[0044] Figure 2 A schematic diagram of a preset non-assignable region corresponding to a current carrier mode being an increase-decrease mode and a current load mode being a shadow mode disclosed by the embodiment of the present application;

[0045] Figure 3 A schematic diagram of a preset non-assignable region corresponding to a current carrier mode being an increase-decrease mode and a current load mode being an immediate mode disclosed by the embodiment of the present application;

[0046] Figure 4 A schematic diagram of a plurality of working condition waveforms of a corresponding comparison value changing before a period value disclosed by the embodiment of the present application;

[0047] Figure 5 A schematic diagram of an abnormal situation when a comparison value is assigned at a load point disclosed by the embodiment of the present application;

[0048] Figure 6 A structural schematic diagram of a PWM modulation device disclosed by the embodiment of the present application;

[0049] Figure 7 A structural schematic diagram of another PWM modulation device disclosed by the embodiment of the present application;

[0050] Figure 8 A structural schematic diagram of still another PWM modulation device disclosed by the embodiment of the present application. DETAILED DESCRIPTION

[0051] The embodiment of the present application provides a PWM modulation method and a PWM modulation device, which are used for PWM modulation in the case of reducing the possibility of abnormality of a PWM modulated signal.

[0052] Please refer to Figure 1 , Figure 1 A flowchart of a PWM modulation method disclosed by the embodiment of the present application is shown in FIG. 1. The method comprises the following steps.

[0053] 101. If a condition of assigning a target parameter to a target parameter value is triggered, it is determined whether a current count value is in a preset unassignable region corresponding to a current mode; wherein the preset unassignable region is a count value near a preset loading point corresponding to the current mode.

[0054] In the embodiment, when PWM modulation is performed, if a condition of assigning a target parameter to a target parameter value is triggered, it is determined whether a current count value is in a preset unassignable region corresponding to a current mode; wherein the preset unassignable region is a count value near a preset loading point corresponding to the current mode.

[0055] 102. If the current count value is in the preset unassignable region, a count value after the current count value is extended for a preset count duration is taken as a target assignment point; wherein the target assignment point is outside the preset unassignable region.

[0056] After it is determined whether the current count value is in the preset unassignable region corresponding to the current mode, if the current count value is in the preset unassignable region, a count value after the current count value is extended for a preset count duration is taken as a target assignment point; wherein the target assignment point is outside the preset unassignable region.

[0057] Before the count value after the current count value is extended for the preset count duration is taken as the target assignment point, the preset count duration can be determined. The method of determining the preset count duration can be that, first, a first count duration consumed for performing the step of determining whether the current count value is in the preset unassignable region corresponding to the current mode is predicted, then a second count duration consumed for performing the step of assigning the target parameter to the target parameter value at the target assignment point is predicted, and finally the preset count duration is determined based on the first count duration and the second count duration. It can be understood that, in addition to the above-described method of determining the preset count duration, other reasonable methods can also be used, which are not limited here.

[0058] 103. The target parameter is assigned to the target parameter value at the target assignment point, so that the target parameter value of the target parameter is obtained at the preset loading point, and a new PWM signal is generated based on the target parameter value of the target parameter.

[0059] After the count value after the current count value is extended for the preset count duration is determined as the target assignment point, the target parameter can be assigned the target parameter value at the target assignment point, so that the target parameter value of the target parameter is obtained at the preset loading point, and a new PWM signal is generated based on the target parameter value of the target parameter.

[0060] In the embodiments of the present application, if the condition of assigning the target parameter to the target parameter value is triggered, it is determined whether the current count value is in a preset non-assignment region corresponding to the current mode, wherein the preset non-assignment region is a count value near the preset loading point corresponding to the current mode. If the current count value is in the preset non-assignment region, the count value after the current count value is extended for the preset count duration is determined as the target assignment point, wherein the target assignment point is outside the preset non-assignment region. The target parameter is assigned the target parameter value at the target assignment point, so that the target parameter value of the target parameter is obtained at the preset loading point, and a new PWM signal is generated based on the target parameter value of the target parameter. By determining whether it is in the preset non-assignment region, a more reasonable assignment point can be determined to bypass the loading point, the probability of missing the carrier zero-crossing point of the current period is small, and the possibility of abnormal signal of PWM modulation is low.

[0061] In the embodiments of the present application, before the count value after the current count value is extended for the preset count duration is determined as the target assignment point, the preset count duration can be determined. The method of determining the preset count duration can be various, based on Figure 1 The PWM modulation method shown in FIG. 1 is described below.

[0062] In the embodiments of the present application, when PWM modulation is performed, it can be determined whether the condition of assigning the target parameter to the target parameter value is triggered. If the condition of assigning the target parameter to the target parameter value is triggered, it is determined whether the current count value is in a preset non-assignment region corresponding to the current mode, wherein the preset non-assignment region is a count value near the preset loading point corresponding to the current mode.

[0063] Specifically, the target parameter can include a period parameter and / or a comparison value parameter, the method of triggering the condition of assigning the target parameter to the target parameter value can be based on an instruction, the instruction can represent assigning the period parameter of the load register to the target period value, and / or assigning the comparison value parameter of the comparison register to the target comparison value. It should be understood that the modulation of the PWM signal (i.e., the modulation of the duty cycle) can determine the frequency through the load register, and can determine the specific duty cycle through the comparison register, wherein the load register is used to store the target period value corresponding to the period parameter, which determines the period of the PWM signal, and the comparison register is used to store the target comparison value corresponding to the comparison value parameter, which determines the high / low level time of the PWM signal, i.e., determines the size of the duty cycle. It can be understood that the target parameter can also be other reasonable parameters, which are not limited here, and the method of triggering the condition of assigning the target parameter to the target parameter value can also be other reasonable methods, which are not limited here.

[0064] Wherein, before determining whether the current count value is in the preset unassignable region corresponding to the current mode, the preset unassignable regions corresponding to various modes can be determined.

[0065] Wherein, the method of determining the preset unassignable regions corresponding to various modes can be, if the current load mode is a shadow mode (shadow register mode), for each falling edge of the carrier, the count value range between the target count value of the falling edge and the zero-crossing point is taken as the preset unassignable region, wherein the shadow mode represents loading at the preset loading point; and the count value difference between the target count value corresponding to the falling edge and the zero-crossing point is a preset count duration, the preset unassignable region is the count value in the preset count duration range at the preset loading point. In other embodiments, the preset loading point is the period value of the carrier, at this time, the unassignable region is located on the rising edge of the carrier, and the count value range between the target count value of the rising edge and the period value is taken as the preset unassignable region.

[0066] And wherein, if the current count value is in the preset unassignable region can be, if the current count value is the count value of the falling edge of the carrier, and the current count value is included in the count value range corresponding to the preset unassignable region, it is determined that the current count value is in the preset unassignable region corresponding to the current mode.

[0067] Specifically, please refer to Figure 2 , Figure 2 A schematic diagram of the preset unassignable region corresponding to the current carrier mode being the increasing / decreasing mode and the current load mode being the shadow mode disclosed by the embodiments of the present application is shown in Figure 2 It can be known that Figure 2The non-assignable region includes a carrier, a time axis, and a period and a CMP value, wherein the non-assignable region of the period and the CMP value is Figure 2 The gray region corresponds to a count value region of the time axis, and the length of the non-assignable region can be a preset count time length. For example, the preset count time length is 25, the preset loading point is the zero-crossing point of the carrier, the target parameters can be the period parameter and the comparison value parameter, the preset loading points of the period parameter and the comparison value parameter can be configured as the zero-crossing point, when the current count value is 23, it can be determined whether the current count value 23 is the count value of the falling edge of the carrier, if yes, it can be determined that the current count value 23 is included in the count value range (25, 0) corresponding to the preset non-assignable region, that is, the count value 25 to the count value 0, and it can be determined that the current count value is in the preset non-assignable region corresponding to the current mode.

[0068] The preset non-assignable region corresponding to the current carrier mode and the current loading mode can be determined as follows: if the current loading mode is an immediate mode (immediate register mode), the preset loading point corresponding to the current mode is determined as the target loading point corresponding to the immediate mode, wherein the immediate mode represents that the current assignment point is taken as the target loading point, and loading is performed immediately at the target loading point, and the current assignment point is any count value. For the rising edge of the carrier, the count value range between the first count value of the rising edge and the target loading point is taken as the preset non-assignable region of the rising edge, wherein the count value difference between the first count value corresponding to the rising edge and the target loading point is the preset count time length; for the falling edge of the carrier, the count value range between the second count value of the falling edge and the target loading point is taken as the preset non-assignable region of the falling edge, wherein the count value difference between the second count value corresponding to the falling edge and the target loading point is the preset count time length, wherein the preset non-assignable region is the count value in the preset count time length range of the preset loading point, the current mode includes the current loading mode and the current carrier mode, and the current carrier mode is the increment-decrement mode.

[0069] And wherein the case that the current count value is in the preset non-assignable region can include at least one of the following cases: if the current count value is the count value of the rising edge of the carrier, and the current count value is included in the count value range corresponding to the preset non-assignable region of the rising edge, it is determined that the current count value is in the preset non-assignable region; if the current count value is the count value of the falling edge of the carrier, and the current count value is included in the count value range corresponding to the preset non-assignable region of the falling edge, it is determined that the current count value is in the preset non-assignable region.

[0070] Specifically, please refer to Figure 3 , Figure 3 The schematic diagram of the preset non-assignable region corresponding to the current carrier mode and the current loading mode is shown in FIG. 1, wherein the current carrier mode is the increment-decrement mode, and the current loading mode is the immediate mode. Figure 3It can be seen that, Figure 3 The non-assignable area includes a carrier, a time axis, and a period and a CMP value, wherein the non-assignable area of the period and the CMP value is Figure 3 The gray area in the formula (1) corresponds to a count value area on the time axis, and the length of the non-assignable area can be a preset count duration. For example, the preset count duration is 25, and the target loading point of the immediate mode is 70. It can be determined that the preset non-assignable area corresponding to the immediate mode is (45, 70) of the rising edge of the carrier and (95, 70) of the falling edge of the carrier. If the current count value is 50, it can be determined whether the current count value 50 is a count value of the falling edge of the carrier or a count value of the rising edge. If it is a count value of the rising edge, it can be determined that the current count value 50 is included in the count value range corresponding to the preset non-assignable area, that is, the count value 45 to the count value 70. It can be determined that the current count value is in the preset non-assignable area corresponding to the current mode. If it is a count value of the falling edge, it can be determined that the current count value 50 is not included in the count value range corresponding to the preset non-assignable area, that is, the count value 95 to the count value 70. It can be determined that the current count value is not in the preset non-assignable area corresponding to the current mode.

[0071] It is worth mentioning that for the immediate loading mode, the non-assignable area corresponding to each target loading point (current assignment point) can be determined in advance. Specifically, as the target loading point moves and changes, the non-assignable area also moves and changes.

[0072] It can be understood that the current carrier mode can be an increase mode, a decrease mode, etc. in addition to the increase and decrease modes, and the specific mode is not limited here.

[0073] The method for determining the preset non-assignable area corresponding to various modes can also be that for the current carrier mode being an increase mode, if the current loading mode is an immediate mode, the preset loading point corresponding to the current mode is determined as the target loading point of the immediate mode. The immediate mode represents that the current assignment point is taken as the target loading point, and the loading is performed immediately at the target loading point. Then, for the rising edge of the carrier, the count value range between the first count value of the rising edge and the target loading point is taken as the preset non-assignable area of the rising edge. The count value difference between the first count value corresponding to the rising edge and the target loading point is a preset count duration.

[0074] The method for determining the preset non-assignable region corresponding to each mode can also be, for the current carrier mode being a minus mode, if the current loading mode is an immediate mode, determining that the preset loading point corresponding to the current mode is a target loading point corresponding to the immediate mode, wherein the immediate mode represents taking the current assignment point as the target loading point and loading immediately at the target loading point, and then for a falling edge of the carrier, taking a count value range between a second count value of the falling edge and the target loading point as a preset non-assignable region of the falling edge; wherein a count value difference between the second count value corresponding to the falling edge and the target loading point is a preset count duration.

[0075] The method for determining the preset non-assignable region corresponding to each mode can also be, for the current carrier mode being a minus mode, if the current loading mode is a shadow mode, for each falling edge of the carrier, taking a count value range between a target count value of the falling edge and a zero-crossing point as a preset non-assignable region; wherein the shadow mode represents loading at a preset loading point; and a count value difference between the target count value corresponding to the falling edge and the zero-crossing point is a preset count duration.

[0076] It can be understood that, in addition to the above-described method for determining the preset non-assignable region corresponding to each mode, other reasonable methods for determining the preset non-assignable region corresponding to each mode can also be used, which are not limited here.

[0077] After determining whether the current count value is in the preset non-assignable region corresponding to the current mode, it can be determined whether the current count value is in the preset non-assignable region, and if the current count value is in the preset non-assignable region, taking a count value after extending the current count value by a preset count duration as a target assignment point; wherein the target assignment point is outside the preset non-assignable region.

[0078] Before taking the count value after extending the current count value by the preset count duration as the target assignment point, the preset count duration can be determined. The method for determining the preset count duration can be, first predicting a first count duration consumed by the step of determining whether the current count value is in the preset non-assignable region corresponding to the current mode, then predicting a second count duration consumed by the step of assigning the target parameter to the target parameter value at the target assignment point, and finally determining the preset count duration based on the first count duration and the second count duration.

[0079] Before determining the preset count duration based on the first count duration and the second count duration, an adjustment count duration can be determined. The method for determining the preset count duration based on the first count duration and the second count duration can be, determining the preset count duration based on the first count duration, the second count duration, and the adjustment count duration.

[0080] Specifically, when PWM modulation is performed, attention needs to be paid to adjusting the actual PWM period, the execution time of the delay statement, the period and the assignment time of the comparison value, that is, the delay time should be greater than (the period & the assignment execution time of the duty cycle value + the judgment execution time of the delay). In actual application, the assignment execution time of the period and the comparison value (duty cycle) can be calculated as t1, the judgment execution time of the delay should be t2, and the delay time T>(t1+t2). For example, T=25>(t1+t2)=12+5, and 8 clock cycle margins are reserved, wherein the delay time is a pre-designed time length, the period & the assignment execution time of the duty cycle value is a second counting time length, the judgment execution time of the delay is a first counting time length, and the reserved clock cycle margin is an adjustment counting time length.

[0081] After the current count value is extended by the pre-designed time length, the count value after the extension can be used as a target assignment point, and the target parameter can be assigned to the target parameter value at the target assignment point, so that the target parameter value of the target parameter is obtained at the pre-set loading point, and a new PWM signal is generated based on the target parameter value of the target parameter.

[0082] After it is determined whether the current count value is in the pre-set unassignable region corresponding to the current mode, before the target parameter is assigned to the target parameter value at the target assignment point, if the current count value is not in the pre-set unassignable region, the current count value can be used as the target assignment point.

[0083] Specifically, please continue to refer to Figure 2 For example, the pre-designed time length is 25, and the pre-set loading point is the zero-crossing point of the carrier. When the current count value is 50, it can be determined whether the current count value 50 is the count value of the falling edge of the carrier. If so, it can be determined that the current count value 50 is not included in the count value range (count value 25 to count value 0) corresponding to the pre-set unassignable region, and it can be determined that the current count value is not in the pre-set unassignable region corresponding to the current mode.

[0084] It is worth mentioning that for the scheme of the current loading mode of the embodiment of the application being a shadow mode, the loading point of the period is generally the zero-crossing point, and the loading point of the comparison value is generally the zero-crossing point and / or the period value. For PWM driving control of DCDC, whether the PWM duty cycle is adjusted or not, the PWM period and the comparison value need to be changed synchronously when the driving period is changed, so the period and the comparison value can be configured to be loaded at the zero-crossing point. Specifically, the method of determining the pre-set loading point as the zero-crossing point of the carrier can be determined by experimental derivation, and the following is based on the description of the experimental derivation process.

[0085] For example, for the 5G outdoor integrated DC power supply project, the TMS320F28069 chip can be used as the control system in the 5G outdoor integrated DC power supply project. When the PWM is configured as a shadow mode (shadow register mode), the PWM period loading is loaded at the carrier zero crossing point by default and cannot be changed. For details, please refer to the description in the TMS320F28069 chip manual.

[0086] For configuration one: the comparison value is loaded at the carrier zero crossing and the period.

[0087] The PWM carrier mode is configured as an increase / decrease mode, and the loading mode is configured as a shadow register mode. In order to ensure that the comparison value can be updated quickly, the PWM comparison value update mode is updated when the carrier count reaches the zero crossing and the period value. The frequency mutation test of the PWM drive is carried out, and the following problems occur in the actual test process:

[0088] (1) When the PWM frequency suddenly changes from 200KHz to 60KHz:

[0089] The PWM frequency suddenly changes from 200KHz to 60KHz (the duty cycle is fixed at 45%). The waveform of PWMA is configured as a rising edge high level and a falling edge low level; the waveform of PWMB is configured as a rising edge low level and a falling edge high level (hereinafter referred to as PWMB). As can be seen from the waveform, whether it is PWMA or PWMB, when the frequency suddenly drops, there are high / low levels that are inconsistent with the frequency before and after switching. Specifically, the comparison value corresponding to 60KHz, 45% duty cycle is greater than the carrier period of 200KHz. If the PWM compares the comparison value at the period value at this time, it will miss the comparison value update point corresponding to the carrier falling edge of the period of 200KHz, and thus the PWM drive needs to wait until the carrier falling edge of the next period is adjusted to 60KHz before it can normally update the drive.

[0090] (2) PWM frequency suddenly changes from 60KHz to 200KHz:

[0091] The PWM frequency suddenly changes from 60KHz to 200KHz (the duty cycle is fixed at 45%). The waveform of PWMA is configured as a rising edge high level and a falling edge low level; the waveform of PWMB is configured as a rising edge low level and a falling edge high level. As can be seen from the waveform, whether it is PWMA or PWMB, when the frequency suddenly increases, there are high / low levels that are inconsistent with the frequency before and after switching. Specifically, because the comparison value corresponding to 200KHz, 45% duty cycle is less than the carrier period of 60KHz, the trigger condition for abnormal drive caused by frequency sudden increase is when the PWM compares the comparison value at the carrier period. If the PWM drive frequency is raised and the comparison value is updated and loaded in advance at the period, an abnormal waveform will occur.

[0092] The reason analysis of the problems appearing in the experimental processes corresponding to the above-mentioned "PWM frequency suddenly changes from 200KHz to 60KHz" and "PWM frequency suddenly changes from 60KHz to 200KHz" is as follows: for the waveforms of various working conditions in which the comparison value changes before the period value, please refer to Figure 4 , Figure 4 The schematic diagram of the waveforms of various working conditions in which the comparison value changes before the period value disclosed by the embodiment of the present application is shown in Figure 4 It can be seen that:

[0093] ①When the frequency is unchanged, the duty cycle increases or decreases, the first waveform of the comparison value after loading is the transition waveform before and after the change, and the actual duty cycle of the waveform is 0.5*(duty cycle before change+duty cycle after change). Under this configuration, the fixed frequency changes the duty cycle, and the transition waveform is a normal phenomenon.

[0094] ②For the PWM port in which the rising edge of the carrier outputs high level and the falling edge outputs low level (i.e. the corresponding PWM drive in Figure 4 ), if the duty cycle of the drive is not 0, it will be high level when loaded at the period; similarly, for the PWM port in which the rising edge of the carrier outputs low level and the falling edge outputs high level, if the duty cycle of the drive is not 0, it will be low level when loaded at the period.

[0095] ③The comparison value is configured to be loaded at the carrier period and zero crossing point. This configuration faces the application scenario in which the PWM period needs to be changed. Whether the duty cycle changes or not, the comparison value of the PWM will be adjusted synchronously according to the period, so the period and the comparison value need to be updated and loaded. When the comparison value is loaded before the period, i.e. the comparison value is loaded at the carrier period and the period is loaded at the next carrier zero crossing point, whether the PWM drive is high level or low level, the actual duty cycle will inevitably be inconsistent with the trend of the theoretical duty cycle.

[0096] After the reason analysis, it is known that the configuration of loading at the carrier period and zero crossing point can ensure that the PWM comparison value can be updated quickly, but this configuration is not suitable for the working condition in which the period and the comparison value need to be loaded repeatedly. If the application working condition does not have high requirements on the PWM duty cycle change accuracy, the measure of limiting the change difference of the PWM frequency before and after loading can avoid the situation that the comparison value is greater than the current carrier period, and thus the actual drive is greatly different from the ideal drive; or the PWM A is loaded at the carrier zero crossing point and the PWM B is loaded at the carrier period point, which can ensure that the PWM A and the PWM B are loaded at the low level period. For the PWM A, the consistency with the period loading can be ensured, but for the PWM B, the comparison value loading will be offset from the period loading point, and when the frequency suddenly drops and the comparison value loading is later than the period loading, the drive signal will be longer than the ideal high level time.

[0097] In summary, the above measures cannot solve the inconsistency between the actual duty ratio and the theoretical duty ratio from the root. Therefore, after weighing the pros and cons of the comparison value being loaded in advance, the comparison value update point of PWMA and PWMB can be adjusted to be consistent with the cycle loading point, that is, the cycle and the comparison value are loaded uniformly at the carrier zero-crossing point.

[0098] It is worth mentioning that after determining that the cycle and the comparison value are loaded uniformly at the carrier zero-crossing point, the PWM modulation abnormal waveform may still occur. For details, see the description of configuration two below.

[0099] For configuration two: the comparison value is loaded only at the carrier zero-crossing point.

[0100] When the PWM count mode is configured as the increment / decrement mode, it is clearly pointed out in the TMS320x2806x manual that in some cases, the loading of the CMPA / CMPB comparison value of the PWM may be delayed for a period of time, so that the comparison value may not be loaded at the loading point in this case when the comparison value is assigned to 0 at the carrier zero-crossing point, or the comparison value is assigned to the carrier period value at the carrier period.

[0101] For configuration two, that is, the cycle and the CMP value (comparison value) are loaded at the carrier zero-crossing point. When TBCTR=0, that is, the carrier count reaches the zero-crossing point, assigning the CMP value to 0 will cause loading abnormality (assigning the CMP value to TBPRT when TBCTR=TBPRT (period value) will also cause loading abnormality). For details, see Figure 5 , Figure 5 is an abnormal situation diagram of the comparison value when the value is assigned at the loading point disclosed in the embodiment of the application, from Figure 5 It can be known that, for example, the CMP value is assigned to 0 at the carrier zero-crossing point, at which time the CMP value can be normally loaded and loaded, but the DSP will miss the rising edge to determine the high / low level, thereby causing the drive to be abnormal for one period. When the drive is triggered to be abnormal, the drive that should normally output the high / low level in a short time will continuously output the reverse level for more than or equal to one period. It needs to be understood that in actual application, the influence caused by such abnormal drive is much worse than that of the lag control. Therefore, the configuration needs to be adopted and the drive needs to be configured as full-on / full-off, and therefore, the problem of carrier zero-crossing drive abnormality needs to be solved.

[0102] It is worth mentioning that existing solutions for resolving carrier zero-crossing drive anomalies can be categorized into two types. The first is to adjust the C phase of the three-phase PWM to the carrier period point for loading. Since the PWM duty cycle cannot reach the period value through limiting, no drive anomalies will occur. The second is to configure the three-phase PWM as in-phase, ensuring that the shadow register update time and the software update value time never overlap under a strong interrupt-PWM drive linkage configuration. However, the solution in this application's embodiment avoids the zero-crossing point when assigning the period and comparison value, thus resolving the carrier zero-crossing drive anomaly problem. For example, regarding the solution in this application's embodiment where the current loading mode is shadow mode, please refer to the following... Figure 2 ,Depend on Figure 2 As can be seen, by adding logic to bypass the zero-crossing / period value based on configuration 2, when preparing to assign the PWM period and comparison value, it can be determined whether the TBCTR carrier count value is close to the carrier zero-crossing / period value. If the count is close to the zero-crossing / period value at this time, it is considered that the PWM period and comparison value cannot be assigned at this time, and the system actively delays for a period of time to bypass the zero-crossing / period value before assigning the value.

[0103] By comparison, it can be seen that, compared with existing solutions for resolving carrier zero-crossing drive anomalies, the current loading mode of this application embodiment, which is a shadow mode, can effectively solve abnormal waveforms caused by sudden changes in frequency or duty cycle due to different PWM loading times, in drive configurations with repeated frequency and duty cycle changes and where control and loading times often overlap. By changing the PWM configuration, it can effectively avoid the abnormal waveforms caused by assigning the loading value to the comparison value at the loading point, as warned in the manual. It can also achieve the effect of not causing abnormal drive even if the PWM duty cycle is assigned a full duty cycle or 0. Furthermore, it can be understood that existing solutions for resolving carrier zero-crossing drive anomalies can only assign values ​​at a fixed time point other than the zero-crossing point, which leads to a higher probability of missing the carrier zero-crossing point of the current cycle. However, this application embodiment determines a more reasonable assignment point by judging whether it is within a preset unassignable area, thus reducing the probability of missing the carrier zero-crossing point of the current cycle.

[0104] It is understandable that, in addition to the methods described above for determining the preset counting duration; in addition to the methods described above for determining the preset counting duration based on the first counting duration and the second counting duration; in addition to the methods described above for determining the preset unassignable region corresponding to the current mode; in addition to the methods described above for determining that the current count value is within the preset unassignable region; other reasonable methods may also be used, and specific methods are not limited here.

[0105] In the embodiment, if a condition of assigning the target parameter to the target parameter value is triggered, it is determined whether the current count value is in a preset non-assignable region corresponding to the current mode, wherein the preset non-assignable region is a count value near a preset loading point corresponding to the current mode. If the current count value is in the preset non-assignable region, a count value after the current count value is extended for a preset count duration is taken as a target assignment point, wherein the target assignment point is outside the preset non-assignable region. The target parameter is assigned to the target parameter value at the target assignment point, so that the target parameter value of the target parameter is obtained at the preset loading point, and a new PWM signal is generated based on the target parameter value of the target parameter. By determining whether the current count value is in the preset non-assignable region, a more reasonable assignment point can be determined to bypass the loading point, and the probability of missing the carrier zero-crossing point of the current period is small. In addition, for a driving configuration condition of repeated frequency conversion and duty cycle variation, by changing the PWM configuration and the bypass loading point assignment scheme, the abnormal waveform of the PWM driving can be effectively avoided when the dynamic frequency conversion and duty cycle variation occur. Secondly, a first count duration consumed in the step of determining whether the current count value is in the preset non-assignable region corresponding to the current mode is predicted, and a second count duration consumed in the step of assigning the target parameter to the target parameter value at the target assignment point is predicted. The preset count duration is determined based on the first count duration and the second count duration, which improves the rationality of determining the preset count duration, thereby reducing the probability of missing the carrier zero-crossing point of the current period and improving the possibility of abnormal waveform of the PWM modulation signal. Finally, the count duration is adjusted, and the preset count duration is determined based on the first count duration, the second count duration and the adjusted count duration, which improves the accuracy of determining the preset count duration.

[0106] The PWM modulation method in the embodiments of the application is described above, and the PWM modulation device in the embodiments of the application is described below. Please refer to Figure 6 The PWM modulation device in the embodiments of the application includes one embodiment:

[0107] The determination unit 601 is configured to determine whether a current count value is in a preset non-assignable region corresponding to a current mode if a condition of assigning a target parameter to a target parameter value is triggered, wherein the preset non-assignable region is a count value near a preset loading point corresponding to the current mode.

[0108] The determination unit 601 is further configured to take a count value after the current count value is extended for a preset count duration as a target assignment point if the current count value is in the preset non-assignable region, wherein the target assignment point is outside the preset non-assignable region.

[0109] The assignment unit 602 is configured to assign the target parameter to the target parameter value at the target assignment point, so that the target parameter value of the target parameter is obtained at the preset loading point, and a new PWM signal is generated based on the target parameter value of the target parameter.

[0110] In the embodiment of the present application, if the condition of assigning the target parameter to the target parameter value is triggered, it is determined whether the current count value is in a preset unassignable region corresponding to the current mode, wherein the preset unassignable region is a count value near the preset loading point corresponding to the current mode. If the current count value is in the preset unassignable region, the count value after the current count value is extended by a preset count duration is taken as a target assignment point, wherein the target assignment point is outside the preset unassignable region. The target parameter is assigned to the target parameter value at the target assignment point, so that the target parameter value of the target parameter is obtained at the preset loading point, and a new PWM signal is generated based on the target parameter value of the target parameter. By determining whether it is in the preset unassignable region, a more reasonable assignment point can be determined to bypass the loading point, and the probability of missing the carrier zero-crossing point of the current period is small, and the possibility of abnormal signal of PWM modulation is low.

[0111] The PWM modulation device in the embodiment of the present application is described in detail below. Please refer to Figure 7 The PWM modulation device in the embodiment of the present application includes another embodiment:

[0112] The determination unit 701 is configured to determine whether the current count value is in a preset unassignable region corresponding to the current mode if the condition of assigning the target parameter to the target parameter value is triggered, wherein the preset unassignable region is a count value near the preset loading point corresponding to the current mode.

[0113] The determination unit 701 is further configured to take the count value after the current count value is extended by a preset count duration as a target assignment point if the current count value is in the preset unassignable region, wherein the target assignment point is outside the preset unassignable region.

[0114] The assignment unit 702 is configured to assign the target parameter to the target parameter value at the target assignment point, so that the target parameter value of the target parameter is obtained at the preset loading point, and a new PWM signal is generated based on the target parameter value of the target parameter.

[0115] The PWM modulation device further includes:

[0116] The prediction unit 703 is configured to predict a first count duration consumed for performing the step of determining whether the current count value is in a preset unassignable region corresponding to the current mode.

[0117] The prediction unit 703 is further configured to predict a second count duration consumed by performing the step of assigning the target parameter to the target parameter value at the target assignment point.

[0118] The determination unit 701 is further configured to determine the preset count duration based on the first count duration and the second count duration.

[0119] The determination unit 701 is further configured to determine an adjusted count duration.

[0120] The determination unit 701 is specifically configured to determine the preset count duration based on the first count duration, the second count duration and the adjusted count duration.

[0121] The determination unit 701 is further configured to determine, if the current loading mode is a shadow mode, a count value range between a target count value of each falling edge of the carrier and a zero-crossing point as a preset unassignable region of the falling edge, wherein the shadow mode represents loading at a preset loading point, a count value difference between the target count value of the falling edge and the zero-crossing point is the preset count duration, the preset unassignable region is a count value in a preset count duration range of the preset loading point, the current mode includes a current loading mode and a current carrier mode, the current carrier mode is an increase-decrease mode, and the preset loading point is a zero-crossing point of the carrier.

[0122] The determination unit 701 is specifically configured to determine, if the current count value is a count value of a falling edge of the carrier and the current count value is included in a count value range corresponding to the preset unassignable region, that the current count value is in the preset unassignable region corresponding to the current mode.

[0123] The determination unit 701 is further configured to determine, if the current loading mode is an immediate mode, that the preset loading point corresponding to the current mode is a target loading point corresponding to the immediate mode, wherein the immediate mode represents taking a current assignment point as the target loading point and loading immediately at the target loading point, and the current assignment point is any count value.

[0124] The determination unit 701 is further configured to determine, for a rising edge of the carrier, a count value range between a first count value of the rising edge and the target loading point as a preset unassignable region of the rising edge, wherein a count value difference between the first count value of the rising edge and the target loading point is the preset count duration.

[0125] The determination unit 701 is further configured to determine a falling edge of the carrier, and take a count value range between a second count value of the falling edge and the target loading point as a preset unassignable region of the falling edge, wherein a count value difference between the second count value of the falling edge corresponding to the target loading point and the target loading point is the preset count duration, the preset unassignable region is a count value in a preset count duration range of the target loading point, the current mode includes a current loading mode and a current carrier mode, and the current carrier mode is an increase-decrease mode.

[0126] The determination unit 701 is specifically configured to determine that the current count value is in the preset unassignable region if the current count value is a count value of a rising edge of the carrier and the current count value is included in a count value range corresponding to a preset unassignable region of the rising edge, and determine that the current count value is in the preset unassignable region if the current count value is a count value of a falling edge of the carrier and the current count value is included in a count value range corresponding to a preset unassignable region of the falling edge.

[0127] The determination unit 701 is further configured to take the current count value as the target assignment point if the current count value is not in the preset unassignable region.

[0128] In the embodiment, each unit in the PWM modulation device performs the operation of the PWM modulation device in the foregoing Figure 1 embodiment, and details are not described herein again.

[0129] Please refer to Figure 8 , another embodiment of the PWM modulation device 800 in the embodiment of the application includes:

[0130] The central processor 801, the memory 804, the input and output interface 803, and the power supply 802;

[0131] The memory 804 is a transitory storage memory or a persistent storage memory.

[0132] The central processor 801 is configured to communicate with the memory 804, and perform instruction operation in the memory 804 to perform the method in the foregoing Figure 1 embodiment.

[0133] The embodiment of the application further provides a computer readable storage medium, the computer readable storage medium includes instructions, when the instructions run on the computer, make the computer perform the method in the foregoing Figure 1 embodiment.

[0134] The embodiment of the present application further provides a computer program product containing instructions, which, when the computer program product is executed on a computer, causes the computer to execute the aforementioned method. Figure 1 The method in the embodiment shown.

[0135] It should be understood that, although each step in the flowchart involved in each embodiment as described above is shown in sequence according to the arrow, these steps are not necessarily executed in sequence according to the arrow. Unless explicitly stated herein, the execution of these steps is not strictly limited in sequence, and these steps can be executed in other sequences. Moreover, at least part of the steps in the flowchart involved in each embodiment as described above can include multiple steps or stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution sequence of these steps or stages is not necessarily sequential, but can be executed alternately or alternately with at least part of other steps or steps or stages in other steps.

[0136] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the system, device and unit described above can refer to the corresponding process in the foregoing method embodiment, which will not be described here.

[0137] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of the units is only a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interface, device or unit, and can be electrical, mechanical or other forms.

[0138] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, that is, they can be located in one place, or can be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0139] In addition, each functional unit in each embodiment of the present application can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of software functional unit.

[0140] The integrated unit, if implemented in the form of a software function unit and sold or used as an independent product, can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application essentially or the part that contributes to the prior art or the whole or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, read-only memory), a random access memory (RAM, random access memory), a magnetic disk or an optical disk, and various media that can store program codes.

Claims

1. A PWM modulation method, characterized by, The method comprises: If a condition of assigning a target parameter to a target parameter value is triggered, determining whether a current count value is in a preset unassignable region corresponding to a current mode; wherein the preset unassignable region is a count value near a preset loading point corresponding to the current mode; If the current count value is in the preset unassignable region, a count value after the current count value is extended for a preset count duration is taken as a target assignment point; wherein the target assignment point is outside the preset unassignable region; At the target assignment point, the target parameter is assigned to the target parameter value, so that the target parameter value of the target parameter is obtained at the preset loading point, and a new PWM signal is generated based on the target parameter value of the target parameter.

2. The method of claim 1, wherein, Before the count value after the current count value is extended for the preset count duration is taken as the target assignment point, the method further comprises: predicting a first count duration consumed for performing the step of determining whether the current count value is in the preset unassignable region corresponding to the current mode; predicting a second count duration consumed for performing the step of assigning the target parameter to the target parameter value at the target assignment point; determining the preset count duration based on the first count duration and the second count duration.

3. The method of claim 2, wherein, Before the preset count duration is determined based on the first count duration and the second count duration, the method further comprises: determining an adjustment count duration; determining the preset count duration based on the first count duration, the second count duration and the adjustment count duration. The preset unassignable region is a count value in a preset count duration range of the preset loading point; the current mode comprises a current loading mode and a current carrier mode; and the current carrier mode is an increase-decrease mode; the preset loading point is a zero-crossing point of a carrier; 4. The method of claim 1, wherein, Before the step of determining whether the current count value is in the preset unassignable region corresponding to the current mode, the method further comprises: If the current loading mode is a shadow mode, for each falling edge of the carrier, a count value range between a target count value of the falling edge and the zero-crossing point is taken as the preset unassignable region; wherein the shadow mode represents loading at the preset loading point; and a count value difference between the target count value corresponding to the falling edge and the zero-crossing point is the preset count duration. The step of determining whether the current count value is in the preset unassignable region corresponding to the current mode, comprises:

5. The method of claim 4, wherein, If the current count value is a count value of a falling edge of the carrier, and the current count value is included in a count value range corresponding to the preset unassignable region, it is determined that the current count value is in the preset unassignable region corresponding to the current mode. The preset unassignable region is a count value in a preset count duration range of the preset loading point; the current mode comprises a current loading mode and a current carrier mode; 6. The method of claim 1, wherein, and the current carrier mode is an increase-decrease mode. ​ Before the determining whether the current count value is in the preset unassignable region corresponding to the current mode, the method further comprises: If the current loading mode is an immediate mode, determining that the preset loading point corresponding to the current mode is a target loading point corresponding to the immediate mode; wherein the immediate mode represents that a current assignment point is taken as the target loading point, and loading is performed immediately at the target loading point; the current assignment point is any one count value; For a rising edge of a carrier, a count value range between a first count value of the rising edge and the target loading point is taken as a preset unassignable region of the rising edge; wherein a count value difference between the first count value corresponding to the rising edge and the target loading point is the preset count duration; For a falling edge of the carrier, a count value range between a second count value of the falling edge and the target loading point is taken as a preset unassignable region of the falling edge; wherein a count value difference between the second count value corresponding to the falling edge and the target loading point is the preset count duration.

7. The method of claim 6, wherein, The determining whether the current count value is in the preset unassignable region corresponding to the current mode comprises at least one of the following: If the current count value is a count value of a rising edge of the carrier, and the current count value is included in a count value range corresponding to a preset unassignable region of the rising edge, it is determined that the current count value is in the preset unassignable region; If the current count value is a count value of a falling edge of the carrier, and the current count value is included in a count value range corresponding to a preset unassignable region of the falling edge, it is determined that the current count value is in the preset unassignable region.

8. The method of claim 1, wherein, After the determining whether the current count value is in the preset unassignable region corresponding to the current mode, before the assigning the target parameter with the target parameter value at the target assignment point, the method further comprises: If the current count value is not in the preset unassignable region, taking the current count value as the target assignment point.

9. A PWM modulation device, characterized by, Comprise: A determining unit is configured to determine whether a current count value is in a preset unassignable region corresponding to a current mode if a condition of assigning a target parameter with a target parameter value is triggered; wherein the preset unassignable region is a count value near a preset loading point corresponding to the current mode; The determining unit is further configured to take a count value after the current count value is extended by a preset count duration as a target assignment point if the current count value is in the preset unassignable region; wherein the target assignment point is outside the preset unassignable region; An assigning unit is configured to assign the target parameter with the target parameter value at the target assignment point, so that the target parameter value of the target parameter is obtained at the preset loading point, and a new PWM signal is generated based on the target parameter value of the target parameter.

10. A PWM modulation device, characterized by, Comprise: A central processing unit and a memory; The memory is a transitory storage memory or a persistent storage memory; The central processing unit is configured to communicate with the memory and execute instruction operations in the memory to perform the method of any one of claims 1-8.

Images