Front-stage PFC and rear-stage DCDC combined control method
阅读说明：本技术 一种前级pfc与后级dcdc联合控制方法 (Front-stage PFC and rear-stage DCDC combined control method ) 是由 任开春 朱爱玉 于 2021-09-30 设计创作，主要内容包括：本发明涉及电力电子技术领域,公开了一种前级PFC与后级DCDC联合控制方法,能根据后级DC/DC输出电压的实际需求,向前级PFC发送调压信号,PFC根据收到的调压信号动态调节自身的输出电压,使输出电压满足后级DC/DC的需求。本发明解决了前级PFC输出电压在特定范围内动态调节输出电压的技术问题,具有使整个AC/DC变换器工作状态更优的有益效果。(The invention relates to the technical field of power electronics, and discloses a front-stage PFC and rear-stage DCDC combined control method which can send a voltage regulating signal to the front-stage PFC according to the actual requirement of the rear-stage DC/DC output voltage, and the PFC dynamically regulates the output voltage of the PFC according to the received voltage regulating signal so that the output voltage meets the requirement of the rear-stage DC/DC. The invention solves the technical problem that the output voltage of the front-stage PFC is dynamically regulated within a specific range, and has the advantage of ensuring that the working state of the whole AC/DC converter is better.)
1. A front-stage PFC and rear-stage DCDC combined control method is characterized by comprising the following steps:
step S1, setting a voltage regulation range of an output voltage U0 of a front-stage PFC main circuit, an output voltage U01 of a rear-stage DC/DC module, a duty ratio of the rear-stage DC/DC module and an output current I01, and sending the output voltage U01, the duty ratio of the DC/DC module and the output current I01 as feedback information to the front-stage PFC main circuit;
step S2, the front-stage PFC main circuit receives the feedback information, adjusts the output voltage U0 of the front-stage PFC main circuit through a preset voltage-adjusting strategy, and sends the output voltage U0 to a rear-stage DC/DC module after the adjustment is finished; the preset voltage regulation strategy is that,
setting a given voltage U1 of a voltage PI regulator and an adjusting coefficient K of a rear-stage DC/DC module, and calculating a front-end voltage U3 of the voltage PI regulator through the given voltage U1 and the adjusting coefficient K;
acquiring output data of a front-stage PFC main circuit to obtain an output voltage sample U11 and an output current sample I8, and calculating through an output voltage sample U11 and the front-stage voltage U3 to obtain a voltage deviation U2;
sending the voltage deviation U2 to a voltage PI regulator, and regulating the output voltage U5 of the voltage PI regulator according to the voltage deviation U2;
collecting the full-wave voltage to obtain a full-wave sampling voltage U6, and calculating the full-wave sampling voltage U6 and the output voltage U5 to obtain a given current I6 of the current PI regulator;
after a given current I6 and the output current sampling I8 are calculated to obtain a current deviation I7, sending the current deviation I7 to a current PI regulator, and regulating the current deviation I7 by the current PI regulator to obtain an output voltage U7;
the current PI regulator sends the output voltage U7 to a front-stage PFC main circuit, the output voltage U7 regulates the front-stage PFC main circuit according to a preset regulation method to obtain an output voltage U0, and the output voltage U0 is sent to a rear-stage DC/DC module;
and step S3, the post-stage DC/DC module receives the output voltage U0, processes the output voltage U0 according to a preset processing scheme and outputs the processed output voltage U0.
2. The method of claim 1, wherein the pre-stage PFC and the post-stage DCDC are jointly controlled by: the output data includes output voltage U0, output current I0, and other data.
3. The method of claim 1, wherein the pre-stage PFC and the post-stage DCDC are jointly controlled by: the given voltage U1 and the adjusting coefficient K are calculated to obtain the front end voltage U3 of the voltage PI regulator, and the given voltage U1 is multiplied by the adjusting coefficient K to obtain the front end voltage U3 of the voltage PI regulator.
4. The method of claim 1, wherein the pre-stage PFC and the post-stage DCDC are jointly controlled by: the voltage deviation U2 calculated by the output voltage sample U11 and the front end voltage U3 is obtained by subtracting the output voltage sample U11 from the front end voltage U3 to obtain a voltage deviation U2.
5. The method of claim 1, wherein the pre-stage PFC and the post-stage DCDC are jointly controlled by: the given current I6 and the output current sample I8 are calculated to obtain a current deviation I7. the given current I6 is subtracted from the output current sample I8 to obtain a current deviation I7.
6. The method of claim 3, wherein the pre-stage PFC and the post-stage DCDC are jointly controlled by: the adjusting coefficient K is a fraction including a denominator and a numerator; the denominator is a given voltage U1 of the voltage PI regulator, and the numerator is the voltage regulation range.
7. The method of claim 6, wherein the pre-stage PFC and the post-stage DCDC are jointly controlled by: the voltage regulating range is 120V-330V; the given voltage U1 is 3.3V.
8. The method of claim 1, wherein the pre-stage PFC and the post-stage DCDC are jointly controlled by: the preset adjusting method is that the output voltage U7 controls and adjusts the duty ratio of the front-stage PFC main circuit.
9. The method of claim 8, wherein the pre-PFC and post-DCDC joint control method comprises: the front-stage PFC main circuit can realize the power factor correction and rectification functions of alternating-current voltage.
10. The method of claim 1, wherein the pre-stage PFC and the post-stage DCDC are jointly controlled by: the preset processing scheme is that a post-stage DC/DC module carries out electrical isolation and voltage transformation processing on the output voltage U0.
Technical Field
The invention relates to the technical field of power electronics, in particular to a front-stage PFC and rear-stage DCDC combined control method.
Background
With the development of power electronics technology, an AC/DC converter has become a common circuit in various circuits, and the AC/DC converter generally consists of a PFC (power factor correction) front stage and a DC/DC (direct current converter) rear stage, so that the optimal state of AC/DC is usually achieved when both PFC and DC/DC are optimal. However, since the PFC usually uses a Boost topology, the voltage of the PFC cannot be adjusted normally, so that the AC/DC cannot always operate in an optimal state.
In order to solve the problem, in the prior art, there is a voltage-adjustable PFC circuit, including a PFC circuit, an inductor LF3 connected to the PFC circuit, a control IC, a voltage feedback loop connected to the control IC, and a resistor R22 connected to the voltage feedback loop, and further including a PFC voltage adjusting circuit, an input end of the PFC voltage adjusting circuit is composed of a diode D15, capacitors C31, C32, and resistors R56 and R57, the input end is connected to a PFC + end after AC rectification to ground, an output end of the PFC voltage adjusting circuit is composed of a comparator U5 and a resistor R58, the output end is connected to the voltage feedback loop, when the AC voltage is low, the comparator U5 is not turned on, the resistor R58 is suspended, the PFC circuit outputs a low voltage, when the AC voltage is high, the comparator U5 is turned on, the resistor R58 is connected in parallel with the resistor R22, and the PFC circuit outputs a high voltage. The power consumption can be reduced, and the working efficiency of the PFC circuit can be improved.
Although the voltage output by the PFC can be adjusted in the scheme, the adjustment range is only between 360V and 420V, and the PFC can only be adjusted upwards at the peak voltage of the maximum input voltage, and the output voltage of the PFC cannot be dynamically adjusted according to the change of actual requirements. Therefore, the technical problem to be solved by the scheme is to realize the dynamic regulation of the output voltage of the PFC within the voltage regulation range.
Disclosure of Invention
The invention aims to provide a front-stage PFC and rear-stage DCDC combined control method, which enables the output voltage of the PFC to be dynamically regulated within a voltage regulation range according to the requirement of rear-stage DC/DC.
In order to achieve the purpose, the invention adopts the following technical scheme: a front-stage PFC and rear-stage DCDC combined control method comprises the following steps:
step S1, setting a voltage regulation range of an output voltage U0 of the front-stage PFC main circuit, an output voltage U01 of a rear-stage DC/DC module, a duty ratio of DC/DC and an output current I01, and sending the output voltage U01, the duty ratio of DC/DC and the output current I01 as feedback information to the front-stage PFC main circuit;
step S2, the front-stage PFC main circuit receives the feedback information, adjusts the output voltage U0 of the front-stage PFC main circuit through a preset voltage-adjusting strategy, and sends the output voltage U0 to a rear-stage DC/DC module after the adjustment is finished; the preset voltage regulation strategy is that,
setting a given voltage U1 of a voltage PI regulator and an adjusting coefficient K of a rear-stage DC/DC module, and calculating a front-end voltage U3 of the voltage PI regulator through the given voltage U1 and the adjusting coefficient K;
acquiring output data of a front-stage PFC main circuit to obtain an output voltage sample U11 and an output current sample I8, and calculating through an output voltage sample U11 and the front-stage voltage U3 to obtain a voltage deviation U2;
sending the voltage deviation U2 to a voltage PI regulator, and regulating the output voltage U5 of the voltage PI regulator according to the voltage deviation U2;
collecting the full-wave voltage to obtain a full-wave sampling voltage U6, and calculating to obtain a given current I6 of the current PI regulator through the full-wave sampling voltage U6 and the output voltage U5;
after a given current I6 and the output current sampling I8 are calculated to obtain a current deviation I7, sending the current deviation I7 to a current PI regulator, and regulating the current deviation I7 by the current PI regulator to obtain an output voltage U7;
the current PI regulator sends the output voltage U7 to a front-stage PFC main circuit, the output voltage U7 regulates the front-stage PFC main circuit according to a preset regulation method to obtain an output voltage U0, and the output voltage U0 is sent to a rear-stage DC/DC module;
and step S3, the post-stage DC/DC module receives the output voltage U0, processes the output voltage U0 according to a preset processing scheme and outputs the processed output voltage U0.
The principle and the advantages of the scheme are as follows: in practical application, a voltage regulation signal is generated according to the requirements of the output voltage and the output power of the rear-stage DC/DC, the given voltage and the regulation coefficient of the regulator are set according to the requirements of the rear-stage DC/DC, the front-end voltage of the voltage PI regulator is obtained by multiplying the given voltage and the regulation coefficient, then the output voltage of the front-stage PFC main circuit is collected to obtain a sampling voltage, the sampling voltage is subtracted from the front-end voltage to obtain a voltage deviation, and therefore the output voltage and the output current of the voltage PI regulator are regulated according to the voltage deviation; and then, acquiring the multiplication of the full-wave voltage and the output voltage of the voltage PI regulator to obtain the given current of the current PI regulator, calculating the current deviation with the output current to regulate the output voltage of the current PI regulator, realizing the regulation of the duty ratio of the front-stage PFC main circuit, and further regulating the output voltage of the front-stage PFC main circuit, so that the output voltage of the front-stage PFC main circuit can be dynamically regulated according to the requirement of a rear-stage DC/DC module, and the AC/DC converter is ensured to always work in an optimal state.
The scheme has the advantages that the output voltage of the front-stage PFC main circuit can be dynamically adjusted through the PI regulator according to the actual requirement of the output voltage or the output power of the rear-stage DC/DC module, so that the output voltage of the rear-stage DC/DC module can be dynamically adjusted within a preset large range, different load requirements are met, and the application range of the AC/DC converter is wider. Compared with the existing adjusting means, the method can be improved from the original fixed voltage value adjustment to the dynamic voltage adjustment, so that the AC/DC converter can reduce power consumption and improve efficiency through the adjustment of internal voltage on the premise of providing a stable output power supply.
Preferably, as a modification, the output data includes an output voltage U0, an output current I0, and other data.
The collected voltage and current data not only can clearly know the working state of the current front-stage PFC main circuit, but also can provide contrast data for the subsequent voltage regulation of the front-stage PFC main circuit; besides voltage and current, other data such as power, voltage amplitude and the like can be collected, and data support can be provided for voltage regulation of a front-stage PFC main circuit.
Preferably, as a modification, the given voltage U1 and the adjustment coefficient K are calculated to obtain the front end voltage U3 of the voltage PI regulator, and the given voltage U1 is multiplied by the adjustment coefficient K to obtain the front end voltage U3 of the voltage PI regulator.
According to the requirement of a rear-stage DC/DC module, a voltage regulation signal, namely a voltage regulation coefficient K, is fed back, a given voltage U1 is multiplied by the regulation coefficient K to obtain a voltage U3, and the voltage U3 is fed back to a voltage PI regulator, so that the output voltage of a front-stage PFC main circuit is regulated, and the purpose of meeting the requirement of the rear-stage DC/DC module is achieved.
Preferably, as a modification, the voltage deviation U2 is calculated by an output voltage sample U11 and the front end voltage U3, and the output voltage sample U11 is subtracted from the front end voltage U3 to obtain a voltage deviation U2.
The actual output voltage of the front-stage PFC main circuit at the current moment is acquired, the voltage deviation is obtained by comparing the actual output voltage with the front-stage voltage of the voltage PI regulator calculated before, and the feedback regulation of the error is realized by the voltage PI regulator, so that the actual output voltage of the front-stage PFC main circuit can meet the use requirement of a rear-stage DC/DC module.
Preferably, as a modification, the given current I6 and the output current sample I8 are calculated to obtain a current deviation I7, and the given current I6 is subtracted from the output current sample I8 to obtain a current deviation I7.
The actual output current of the front-stage PFC main circuit can meet the requirement of a rear-stage DC/DC module by calculating the error between the actual output current at the current moment and the given current and feeding the error back to the current PI regulator to regulate the output current.
Preferably, as an improvement, the adjustment coefficient K is a fraction including a denominator and a numerator; the denominator is a given voltage U1 of the voltage PI regulator, and the numerator is the voltage regulation range.
The denominator of the regulating coefficient K is the given voltage U1, the numerator is any value in the voltage regulating range, and the regulating coefficient K is determined according to the given voltage and the voltage regulating range of the front-stage PFC main circuit, so that the final regulation of the output voltage of the front-stage PFC main circuit is more accurate, the accuracy of voltage regulation is improved, and the working effect of the AC/DC converter is ensured.
Preferably, as an improvement, the voltage regulation range is 120V-330V; the given voltage U1 is 3.3V.
According to the requirements of a rear-stage DC/DC module, the voltage regulating range of a front-stage PFC main circuit is set to be 120V-330V, so that the output voltage of the front-stage PFC main circuit is dynamically regulated in the range, the output voltage of the rear-stage DC/DC module is dynamically regulated, the output voltage of the rear-stage DC/DC module can meet the requirements, and finally the AC/DC converter always works in an optimal state; the specific size of the given voltage is matched with the regulating coefficient K, and the final purpose is to enable the PFC regulating range to meet the requirement of 120V-330V and enable the whole voltage regulating work to be carried out smoothly.
Preferably, as an improvement, the preset adjusting method is that the output voltage U7 controls and adjusts the duty ratio of the front-stage PFC main circuit.
The output voltage U7 is used for adjusting the duty ratio of the front-stage PFC main circuit, so that the voltage of the front-stage PFC main circuit is changed, and the output voltage of the front-stage PFC main circuit is adjusted.
Preferably, as an improvement, the front-stage PFC main circuit can implement power factor correction and rectification functions of the alternating current.
In the front-stage PFC main circuit, the current waveform of the input alternating current is controlled to be synchronous with the input voltage waveform, so that the power factor is improved; after the power factor correction is finished, the voltage is rectified and then transmitted to a post-stage DC/DC module.
Preferably, as an improvement, the preset processing scheme is that a post-stage DC/DC module performs electrical isolation and voltage transformation processing on the output voltage U0.
The rear-stage DC/DC module isolates the input voltage, the influence of interference brought by primary-side equipment on the whole AC/DC converter can be effectively isolated, the subsequent load connected with the DC/DC can work stably, meanwhile, the voltage is transformed according to the requirement, the adjustment of the output voltage is realized by setting different duty ratios in the rear-stage DC/DC module, the load requirement can be met, and the AC/DC converter is ensured to be in the optimal working state.
Drawings
Fig. 1 is a schematic diagram of a voltage regulation principle of a first embodiment of a combined control method of a front-stage PFC and a rear-stage DCDC according to the present invention.
Fig. 2 is a schematic diagram of a PI regulator according to a first embodiment of the combined control method for a front-stage PFC and a rear-stage DCDC according to the present invention.
Detailed Description
The following is further detailed by way of specific embodiments:
reference numerals in the drawings of the specification include: the device comprises a voltage PI regulator 1, a current PI regulator 2, a front-stage PFC main circuit 3 and a rear-stage DC/DC module 4.
The first embodiment is as follows:
this embodiment is substantially as shown in figure 1: a front-stage PFC and rear-stage DCDC combined control method comprises the following steps:
step S1 is to set a voltage regulation range of the output voltage U0 of the front-stage PFC main circuit 3, and the output voltage U01, the duty ratio of DC/DC, and the output current I01 of the rear-stage DC/DC module 4, and to send the output voltage U01, the duty ratio of DC/DC, and the output current I01 as feedback information to the front-stage PFC main circuit 3.
Step S2, the former PFC main circuit 3 receives the feedback information, adjusts the output voltage U0 of the former PFC main circuit 3 through a preset voltage regulation strategy, and sends the output voltage U0 to the latter DC/DC module 4 after the adjustment is completed; the preset voltage regulation strategy is that,
setting a given voltage U1 of the voltage PI regulator 1 and an adjusting coefficient K of a rear-stage DC/DC module 4, and calculating a front-end voltage U3 of the voltage PI regulator 1 through the given voltage U1 and the adjusting coefficient K;
acquiring output data of a front-stage PFC main circuit 3 to obtain an output voltage sample U11 and an output current sample I8, and calculating through an output voltage sample U11 and the front-stage voltage U3 to obtain a voltage deviation U2;
sending the voltage deviation U2 to a voltage PI regulator 1, and the voltage PI regulator 1 regulates the output voltage U5 thereof according to the voltage deviation U2 and sends the output voltage U5 to a current PI regulator 2;
collecting the full-wave voltage to obtain a full-wave sampling voltage U6, and calculating a given current I6 of the current PI regulator 2 through the full-wave sampling voltage U6 and the output voltage U5;
after a given current I6 and the output current sample I8 are calculated to obtain a current deviation I7, the current deviation I7 is sent to a current PI regulator 2, and the current deviation I7 is regulated by the current PI regulator 2 to obtain an output voltage U7;
the current PI regulator 2 sends the output voltage U7 to the front-stage PFC main circuit 3, the output voltage U7 regulates the front-stage PFC main circuit 3 according to a preset regulation method to obtain an output voltage U0, and sends the output voltage U0 to the rear-stage DC/DC module 4.
In step S3, the post-stage DC/DC module 4 receives the output voltage U0, processes the output voltage U0 according to a preset processing scheme, and outputs the processed output voltage U0.
As shown in fig. 2, a PI regulator, i.e., a proportional-integral regulator, is a linear controller that forms a control deviation from a given value and an actual output value, and linearly combines the proportion and the integral of the deviation to form a control amount to control an object to be controlled. The voltage PI regulator 1 and the current PI regulator 2 can adjust the error of the voltage and the current of the AC/DC converter according to a proportional and integral adjustment method.
The full-wave voltage is a voltage which is formed by rectifying a part of the sinusoidal voltage which is smaller than zero into a voltage which is larger than zero and has a positive waveform.
In this embodiment, the voltage regulation range is 120V to 330V, the voltage conversion ratio of the adopted rear-stage DC/DC module 4 is 1/5, the actual output voltage U01 is 40V, and the actual output voltage of the front-stage PFC main circuit 3 is 200V; when the output voltage U01 is set to 48V, the output voltage U0 of the former-stage PFC is 240V, and the regulation coefficient K of the later-stage DC/DC module 4 is 240/330. In order to meet the setting requirements of the voltage and the current of a control loop formed by a voltage PI regulator and a current PI regulator, the voltage and the current actually output by the front-stage PFC main circuit are reduced by 100 times and fed back to the control loop formed by the voltage PI regulator and the current PI regulator.
After the output voltage value of the rear-stage DC/DC module 4 is set according to the requirement of the rear-stage DC/DC module 4, the specific voltage value to be regulated can be obtained by multiplying the feedback regulation coefficient K by the set given voltage U1, then comparing the collected actual output voltage of the front-stage PFC main circuit 3 with the regulated voltage to obtain a voltage deviation, the output voltage and the output current of the voltage PI regulator 1 are regulated through voltage deviation, then the full-wave voltage is collected to be multiplied by the output voltage of the voltage PI regulator 1 to obtain the given current of the current PI regulator 2, then the output voltage of the current PI regulator 2 is regulated by calculating the current deviation with the output current, the regulation of the duty ratio of the front-stage PFC main circuit 3 is realized, and further, the effective voltage value of the front-stage PFC main circuit 3 is adjusted, and finally, the input voltage of the rear-stage DC/DC module 4 is adjusted. The whole adjusting process is simple and clear, and the adopted voltage value is also common and easily-obtained voltage, so that the adjustment of the output voltage of the front-stage PFC main circuit 3 is more convenient.
The specific implementation process of the embodiment is as follows:
in the first step, the voltage regulation range of the output voltage U0 of the front-stage PFC main circuit 3 is set to 120V-330V, the output voltage U01 of the rear-stage DC/DC module 4 is set to 48V, the voltage conversion ratio of the rear-stage DC/DC module 4 is set to 1/5, the output current I01 is set to 2A, and the output voltage U01, the duty ratio of DC/DC, and the output current I01 are sent to the front-stage PFC main circuit 3 as feedback information.
Secondly, the front-stage PFC main circuit 3 receives the feedback information, sets the given voltage U1 of the voltage PI regulator 1 to be 3.3V and the regulation coefficient K of the rear-stage DC/DC module 4 to be 240/330, and multiplies the given voltage U1 by the regulation coefficient K to obtain the front-stage voltage U3 of the voltage PI regulator 1 to be 2.4V.
Thirdly, acquiring output data of a front-stage PFC main circuit 3 to obtain an output voltage sample U11 of 2V, and subtracting the output voltage U11 from a front-stage voltage U3 to obtain a voltage deviation U2 of 2.4V-2V which is 0.4V; the voltage deviation U2 is sent to the voltage PI regulator 1, because the voltage deviation U2 is positive, which indicates that the front-end voltage U3 is greater than the output voltage U11, and the voltage PI regulator 1 increases its output voltage U5 to 2.4V output.
And fourthly, collecting full-wave voltage to obtain full-wave sampling voltage U6, multiplying the full-wave sampling voltage U6 by the output voltage U5 to obtain a given current I6 of the current PI regulator 2, enabling the waveform of the output current to be a sine wave identical to the voltage waveform, subtracting the output current sample I8 of the front-stage PFC main circuit 3 from the given current I6 to obtain a current deviation I7, sending the current deviation I7 to the current PI regulator 2, and regulating the current deviation I7 by the current PI regulator 2 to obtain an output voltage U7.
And fifthly, the current PI regulator 2 sends the output voltage U7 to the front-stage PFC main circuit 3, the output voltage U7 controls and regulates the duty ratio of the front-stage PFC main circuit 3 to obtain an output voltage U0, and the output voltage U0 is sent to the rear-stage DC/DC module 4.
And sixthly, the rear-stage DC/DC module 4 receives the output voltage U0, performs electrical isolation and voltage transformation on the output voltage U0 to obtain an output voltage U01 of 48V, and the output voltage U01 is equal to a set value, so that voltage regulation is finished.
According to the scheme, the voltage PI regulator and the current PI regulator are utilized, the real-time dynamic regulation of the output voltage of the front-stage PFC main circuit 3 between 120-330V can be realized, the voltage regulation range is large, the requirements of a rear-stage DC/DC module can be self-adapted, and the whole regulation process is more intelligent. On the one hand, the PI regulator has a high requirement on a regulating circuit in the actual operation process, and in the industry, a power supply with a specific voltage value is usually directly adopted because of the fixity of the rated voltage of a load. According to the scheme, the output voltage of the front-stage PFC main circuit 3 can be dynamically adjusted within a large range of 120-330V, so that the output voltage is suitable for loads with different requirements, meanwhile, the voltage can be subjected to proportional and integral adjustment through the PI regulator, the effectiveness and the accuracy of voltage adjustment are guaranteed, and the damage of circuit elements caused by the fact that the actual voltage exceeds the load requirement is avoided by adjusting the output voltage.
Example two:
this embodiment is basically the same as the first embodiment, except that: the actual output voltage U01 of the rear-stage DC/DC module 4 is 36V, and the actual output voltage of the front-stage PFC main circuit 3 is 180V; when the output voltage U01 is set to 24V, the output voltage U0 of the former-stage PFC is 120V, and the regulation coefficient K of the later-stage DC/DC module 4 is 120/330.
The actual output voltage of the front-stage PFC main circuit 3 and the rear-stage DC/DC module 4 is changed, the output voltage of the rear-stage DC/DC module 4 is reduced on the original basis, the voltage regulation direction is changed, and the capability that the output voltage of the front-stage PFC main circuit 3 can be regulated at will between 120V and 330V is tested.
The specific implementation process of this embodiment is basically the same as that of the first embodiment, except that:
firstly, the voltage regulation range of the output voltage U0 of the front-stage PFC main circuit 3 is set to be 120V-330V, the output voltage U01 of the rear-stage DC/DC module 4 is set to be 24V, the voltage conversion ratio of the rear-stage DC/DC module 4 is 1/5, the output current I01 is set to be 2A, the output voltage U0 of the front-stage PFC is 120V, and the output voltage U01, the duty ratio of DC/DC and the output current I01 are sent to the front-stage PFC main circuit 3 as feedback information.
Secondly, the front-stage PFC main circuit 3 receives the feedback information, sets the given voltage U1 of the voltage PI regulator 1 to be 3.3V and the regulation coefficient K of the rear-stage DC/DC module 4 to be 120/330, and multiplies the given voltage U1 by the regulation coefficient K to obtain the front-stage voltage U3 of the voltage PI regulator 1 to be 1.2V.
Thirdly, acquiring output data of a front-stage PFC main circuit 3 to obtain an output voltage sample U11 of 1.8V, and subtracting the output voltage U11 from a front-stage voltage U3 to obtain a voltage deviation U2 of 1.2V-1.8V-0.6V; the voltage deviation U2 is sent to the voltage PI regulator 1, because the voltage deviation U2 is negative, which means that the front-end voltage U3 is smaller than the output voltage U11, and the voltage PI regulator 1 reduces its output voltage U5 to 1.2V output.
The output voltage of the front-stage PFC main circuit 3 is reduced through feedback regulation by simulating the actual output voltage of the rear-stage DC/DC module when the load is suddenly reduced, so that the reduction regulation of the output voltage of the rear-stage DC/DC module is achieved, and the output voltage of the front-stage PFC main circuit 3 can be changed according to the actual requirement of the rear-stage DC/DC module through combination comparison with the first embodiment, so that dynamic regulation is carried out among preset 120-phase 330V, the working state of the AC/DC converter is always in an optimal state, and the actual requirement change of different loads can be met.
Example three:
this embodiment is basically the same as the first embodiment, except that: when the full-wave voltage is collected, the full-wave voltage with the effective value of 1V is selected.
After the full-wave voltage with the voltage effective value of 1V is multiplied by the output current, the obtained output current value is unchanged, but the waveform is changed into a sine wave which is the same as the output voltage, and a single variable is controlled, so that the adjusting process is simpler and more convenient.
The specific implementation process of this embodiment is the same as that of the first embodiment, except that:
and fourthly, acquiring full-wave voltage waveform with the effective value of 1V to obtain full-wave sampling voltage U6, multiplying the full-wave sampling voltage U6 by the output voltage U5 to obtain given current I6 of the current PI regulator 2, enabling the waveform of the output current to be changed into a sine wave identical to the output voltage, subtracting the output current I8 of the front-stage PFC main circuit 3 from the given current I6 to obtain current deviation I7, sending the current deviation I7 to the current PI regulator 2, and adjusting the current deviation I7 by the current PI regulator 2 to obtain output voltage U7.
After the regulation of the voltage PI regulator, the output voltage of the voltage PI regulator is rectified, the full-wave voltage with the effective value of 1V is sampled, and after the full-wave voltage is multiplied by the output voltage of the voltage PI regulator, the waveform of the output voltage of the voltage PI regulator can be adjusted only without influencing the voltage, so that the influence factors in the regulation process are reduced, and the whole regulation is simpler and faster.
Example four:
this embodiment is substantially the same as the first embodiment, except that: the load requirement of the rear-stage DC/DC module 4 is collected in real time, and an adjusting signal is sent to the front-stage PFC main circuit 3 according to the load requirement. For example, the load of the rear stage DC/DC module 4 suddenly increases, resulting in a voltage that needs to be reduced from the current 26V to 25V.
The load demand and the load change of the rear-stage DC/DC module 4 are collected and fed back to the front-stage PFC main circuit 3 in real time according to the demand of the rear-stage DC/DC module 4, so that the front-stage PFC main circuit 3 dynamically adjusts the output voltage of the front-stage PFC main circuit 3 according to the load change of the rear-stage DC/DC module 4, the intelligent dynamic adjustment of the AC/DC converter is realized, and the AC/DC converter is in an optimal working state for a long time.
The specific implementation process of this embodiment is as follows:
firstly, setting the voltage regulation range of the output voltage U0 of the front-stage PFC main circuit 3 to be 120V-330V, the current output voltage U01 of the rear-stage DC/DC module 4 to be 26V, and the voltage conversion ratio of the rear-stage DC/DC module 4 to be 1/5, wherein the output voltage U0 of the front-stage PFC is 130V; when the load of DC/DC suddenly increases and the output voltage U01 decreases to 25V, the value 25V of the output voltage U01 is sent to the front-stage PFC main circuit 3 as feedback information.
Secondly, the front-stage PFC main circuit 3 receives the feedback information, sets the given voltage U1 of the voltage PI regulator 1 to be 3.3V and the regulation coefficient K of the rear-stage DC/DC module 4 to be 150/330, and multiplies the given voltage U1 by the regulation coefficient K to obtain the front-stage voltage U3 of the voltage PI regulator 1 to be 1.5V.
Thirdly, acquiring output data of a front-stage PFC main circuit 3 to obtain an output voltage sample U11 of 1.3V, and subtracting the output voltage U11 from a front-stage voltage U3 to obtain a voltage deviation U2 of 1.5V-1.3V-0.2V; the voltage deviation U2 is sent to the voltage PI regulator 1, because the voltage deviation U2 is positive, which indicates that the front-end voltage U3 is greater than the output voltage U11, and the voltage PI regulator 1 increases its output voltage U5 to 1.5V output.
And fourthly, collecting the full-wave voltage to obtain a full-wave sampling voltage U6, multiplying the full-wave sampling voltage U6 by the output voltage U5 to obtain a given current I6 of the current PI regulator 2, enabling the waveform of the output current to be a sine wave identical to the voltage waveform, subtracting the output current I8 of the front-stage PFC main circuit 3 from the given current I6 to obtain a current deviation I7, sending the current deviation I7 to the current PI regulator 2, and regulating the current deviation I7 by the current PI regulator 2 to obtain an output voltage U7.
And fifthly, the current PI regulator 2 sends the output voltage U7 to the front-stage PFC main circuit 3, the output voltage U7 controls and regulates the duty ratio of the front-stage PFC main circuit 3 to obtain an output voltage U0, and the output voltage U0 is sent to the rear-stage DC/DC module 4.
And sixthly, the rear-stage DC/DC module 4 receives the output voltage U0, performs electrical isolation and voltage transformation treatment on the output voltage U0 to obtain an output voltage U01 of 25V, and if the load requirement is met, the voltage regulation is finished.
The load change of the rear-stage DC/DC module is collected in real time, so that the adjusting direction of voltage adjustment is obtained, after the load change is fed back to the PI adjuster, the output voltage adjusting range of the voltage PI adjuster is determined through the fed back adjusting coefficient K, so that the whole adjusting process is simpler and faster, the change requirement of the system load can be adjusted and fed back quickly, the working state of the load and the working state of the AC/DC converter are both in the optimal state, and the maximum utilization of electric energy is realized.
The foregoing is merely an example of the present invention and common general knowledge in the art of designing and/or characterizing particular aspects and/or features is not described in any greater detail herein. It should be noted that, for those skilled in the art, without departing from the technical solution of the present invention, several variations and modifications can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicability of the patent. The scope of the claims of the present application shall be determined by the contents of the claims, and the description of the embodiments and the like in the specification shall be used to explain the contents of the claims.