CN110601571A - Control method of DC-DC converter - Google Patents
Control method of DC-DC converter Download PDFInfo
- Publication number
- CN110601571A CN110601571A CN201910840691.9A CN201910840691A CN110601571A CN 110601571 A CN110601571 A CN 110601571A CN 201910840691 A CN201910840691 A CN 201910840691A CN 110601571 A CN110601571 A CN 110601571A
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- pwm
- duty ratio
- current
- converter
- value
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Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/14—Arrangements for reducing ripples from dc input or output
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
- H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
- H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
- H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/21—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/217—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M7/219—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only in a bridge configuration
Abstract
The invention discloses a control method of a DC-DC converter.A DC-DC conversion circuit comprises a group of bridge arms consisting of two switching tubes T1 and T2, and the bridge arms charge a power battery pack through an LC circuit consisting of an inductor L and a capacitor C which are connected in series and a load resistor R; collecting charging voltage u of DC-DC converteroCharging current ioAnd the inductor current iLAnd sending the sampled data to a controller, which calculates an inductor current reference value irefFurther calculate the inductance current error value Δ iLWhile calculating the charging voltage error value DeltauoAnd finally, calculating a PWM output duty ratio d according to the two error values, sending the PWM output duty ratio d to a PWM module in the DSP, and outputting PWM signals with the corresponding duty ratio d to two switching tubes of the DC-DC conversion circuit by the PWM module. The control method of the DC-DC converter introduces the inductance current reference value, and is effectiveThe influence of input voltage fluctuation is inhibited, the robustness is strong, the response speed is high, the controller is simple in structure, the calculated amount is small, and the occupied DSP resources are few; an automatic parameter setting method can be adopted, and parameter debugging is facilitated.
Description
Technical Field
The present invention relates to a DC-DC converter, and more particularly, to a method for controlling a DC-DC converter.
Background
In the project of the existing high-integration controller multiplexing charger and booster, when the controller works in a charging mode, the whole circuit structure can be divided into a front-stage PWM (pulse width modulation) rectifying circuit and a rear-stage DC-DC converter circuit, and due to the inherent characteristics of the front-stage PWM rectifying circuit, the output rectified voltage of the front-stage PWM rectifying circuit contains large ripples, so that the rear-stage DC-DC converter is required to inhibit the influence of the DC bus voltage ripples.
The existing control method of the rear-stage DC-DC converter is three closed-loop control of output voltage, inductive current and load current. The method has a slow response speed, and cannot well inhibit the influence of input voltage ripples, so that the charging voltage ripples are still large.
The existing three-closed-loop control strategy of the DC-DC converter for output voltage, inductive current and load current needs three PI controllers, occupies DSP calculation resources, and is relatively troublesome in parameter setting; and the response speed of the three-closed-loop control is low, so that the influence of input voltage ripples cannot be well inhibited, and the charging voltage ripples are still large.
Disclosure of Invention
The invention aims to: the control method of the DC-DC converter is provided, meets the stability requirement and the rapidity requirement of the system under the condition of low computing resource occupation, large input voltage fluctuation and load change, and ensures that the output ripple waves are in a specified range
The technical scheme of the invention is as follows:
a control method of a DC-DC converter comprises a front-stage PWM rectification circuit and a rear-stage DC-DC conversion circuit, wherein the DC-DC conversion circuit comprises a group of bridge arms consisting of two switching tubes T1 and T2, and the bridge arms charge a power battery pack through an LC circuit consisting of an inductor L and a capacitor C which are connected in series and a load resistor R;
the control method comprises the following steps: collecting charging voltage u of DC-DC converter by adopting sampling unitoCharging current ioAnd the inductor current iLAnd sending the sampled data to a controller, which calculates an inductor current reference value irefFurther calculate the inductance current error value Δ iLWhile calculating the charging voltage error value DeltauoAnd finally, calculating a PWM output duty ratio d according to the two error values, sending the PWM output duty ratio d to a PWM module in the DSP, and outputting PWM signals with the corresponding duty ratio d to two switching tubes of the DC-DC conversion circuit by the PWM module.
Preferably, the inductor current reference value irefThe calculation method comprises the following steps:
according to the energy conservation theorem, when the upper bridge arm switching tube T1 is switched on and the lower bridge arm switching tube T2 is switched off, deducing that:
when T1 is off and T2 is on, no energy is transferred from the input to the output load, at which time the energy is compensated by the energy stored in the inductor and the energy stored in the capacitor when T1 is on;
assuming that the capacitor voltage is constant during a switching cycle, the inductor current reference value is:
the load resistance is derived as:
the inductor current reference value is then:
preferably, the inductor current error value Δ iLFrom the inductor current reference value irefSubtracting the sampled inductor current iLObtaining; the charging voltage error value DeltauoCharging by power batteryPressure reference value urefSubtracting the sampled charging voltage uoThus obtaining the product.
Preferably, the method for calculating the PWM output duty ratio d according to the two error values comprises: the inductor current error value Δ iLMultiplying the current gain K to obtain a duty ratio component d 1; charging voltage error value delta uoObtaining a duty ratio component d2 through a PI controller; and adding the duty ratio components d1 and d2 to obtain a duty ratio d, wherein the amplitude limit of d is between 0 and 1.
Preferably, the controller multiplies the duty ratio d by a count value corresponding to the current PWM period and performs rounding to obtain a corresponding CMP value, and sends the CMP value into a register of a PWM module in the DSP.
Preferably, the PWM module in the DSP triggers two interrupts in one switching cycle, and after the interrupt is entered, the controller first calls the voltage and current sampling program to obtain real-time voltage and current data, and then transmits the corresponding data to the algorithm program.
Preferably, when charging current ioWhen the measurement cannot be carried out, equivalent replacement is carried out by using the capacitance C value, and the following results are obtained:
preferably, the PWM rectification circuit comprises two sets of bridge arms formed by four switching tubes, and the PWM rectification circuit operates in a bipolar modulation state to rectify the single-phase power frequency grid voltage into a DC high voltage to be transmitted to the DC-DC conversion circuit.
The invention has the advantages that:
1. the control method of the DC-DC converter introduces the reference value of the inductive current, effectively inhibits the influence of the fluctuation of the input voltage, and has strong robustness and high response speed
2. The controller of the invention has simple structure, small calculated amount and less occupied DSP resources;
3. the invention can adopt an automatic parameter setting method, thereby facilitating parameter debugging.
Drawings
The invention is further described with reference to the following figures and examples:
FIG. 1 is a schematic diagram of the overall structure of a DC-DC converter;
FIG. 2 is a schematic diagram of a DC-DC converter circuit;
FIG. 3 is a schematic diagram of a control structure of the DC-DC converter;
FIG. 4 is a schematic diagram of a control algorithm of the DC-DC converter;
fig. 5 is a schematic diagram of another control algorithm structure of the DC-DC converter.
Detailed Description
As shown in fig. 1, the present embodiment provides a method for controlling a DC-DC converter under a variable voltage input condition, which applies a basic circuit structure of a scene multiplexing charger, and includes a PWM rectification circuit at a front stage and a DC-DC conversion circuit at a rear stage. The PWM rectification circuit comprises two groups of bridge arms formed by four switch tubes, works in a bipolar modulation state, rectifies single-phase power frequency power grid voltage into direct current high voltage and transmits the direct current high voltage to the DC-DC conversion circuit.
As shown in fig. 2, the DC-DC conversion circuit includes a set of arms formed by two IGBT switching tubes T1 and T2, the IGBT switching tubes T1 and T2 correspond to the anti-parallel diodes D1 and D2, and the arms charge the power battery pack through an LC circuit formed by an inductor L and a capacitor C connected in series and a load resistor R.
The specific control method of the DC-DC converter of the present embodiment is as follows:
the PWM module in the DSP triggers two times of interruption in one switching period, wherein one switching period is 50us, after the interruption, the controller calls a voltage and current sampling program to obtain real-time voltage and current data, and then transmits the corresponding data into an algorithm program. As shown in FIG. 3, the charging voltage u of the DC-DC converter is collected by a sampling unitoCharging current ioAnd the inductor current iLAnd sending the sampled data to a controller, wherein a control algorithm of the controller is shown in fig. 4 and comprises the following steps:
firstly, an inductance current reference value i is calculatedrefThe calculation method of the inductance current reference value comprises the following steps:
according to the energy conservation theorem, when the upper bridge arm switching tube T1 is switched on and the lower bridge arm switching tube T2 is switched off, deducing that:
when T1 is off and T2 is on, no energy is transferred from the input to the output load, at which time the energy is compensated by the energy stored in the inductor and the energy stored in the capacitor when T1 is on;
assuming that the capacitor voltage is constant during a switching cycle, the inductor current reference value is:
the load resistance is derived as:
the inductor current reference value is then:
further calculate the inductance current error value DeltaiLThe value of the inductor current error Δ iLFrom the inductor current reference value irefSubtracting the sampled inductor current iLThus obtaining the product.
Simultaneously calculating the charging voltage error value DeltauoThe charging voltage error value DeltauoFrom a reference value u of the charging voltage of the power batteryrefSubtracting the sampled charging voltage uoThus obtaining the product.
And finally, calculating a PWM output duty ratio d according to the two error values, sending the duty ratio d to a PWM module in the DSP, and outputting PWM signals with corresponding duty ratios d to two switching tubes of the DC-DC conversion circuit by the PWM module. The method for calculating the PWM output duty ratio d comprises the following steps: the inductor current error value Δ iLMultiplying the current gain K to obtain a duty ratio component d 1; charging voltage error value delta uoObtaining a duty ratio component d2 through a PI controller; and adding the duty ratio components d1 and d2 to obtain a duty ratio d, wherein the amplitude limit of d is between 0 and 1.
The controller multiplies the duty ratio d by the count value corresponding to the current PWM period and performs rounding to obtain a corresponding CMP value, and the CMP value is sent into a register of a PWM module in the DSP.
When charging current ioWhen the measurement cannot be performed, other measurement variables need to be equivalently replaced, and as shown in fig. 5, the capacitance C value is equivalently replaced to obtain:
the other algorithm structure is the same as that shown in fig. 4.
The above embodiments are merely illustrative of the technical ideas and features of the present invention, and the purpose of the embodiments is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the protection scope of the present invention. All modifications made according to the spirit of the main technical scheme of the invention are covered in the protection scope of the invention.
Claims (8)
1. The control method of the DC-DC converter is characterized in that the DC-DC converter comprises a front-stage PWM rectification circuit and a rear-stage DC-DC conversion circuit, the DC-DC conversion circuit comprises a group of bridge arms consisting of two switching tubes T1 and T2, and the bridge arms charge a power battery pack through an LC circuit consisting of an inductor L and a capacitor C which are connected in series and a load resistor R;
the control method comprises the following steps: collecting charging voltage u of DC-DC converter by adopting sampling unitoCharging current ioAnd the inductor current iLAnd sending the sampled data to a controller, which calculates an inductor current reference value irefFurther calculate the inductance current error value Δ iLWhile calculating the charging voltage error value DeltauoAnd finally, calculating a PWM output duty ratio d according to the two error values, sending the PWM output duty ratio d to a PWM module in the DSP, and outputting PWM signals with the corresponding duty ratio d to two switching tubes of the DC-DC conversion circuit by the PWM module.
2. The control system of claim 1, wherein the DC-DC converterThe reference value i of the inductor currentrefThe calculation method comprises the following steps:
according to the energy conservation theorem, when the upper bridge arm switching tube T1 is switched on and the lower bridge arm switching tube T2 is switched off, deducing that:
when T1 is off and T2 is on, no energy is transferred from the input to the output load, at which time the energy is compensated by the energy stored in the inductor and the energy stored in the capacitor when T1 is on;
assuming that the capacitor voltage is constant during a switching cycle, the inductor current reference value is:
the load resistance is derived as:
the inductor current reference value is then:
3. the control system of claim 2, wherein the inductor current error value Δ iLFrom the inductor current reference value irefSubtracting the sampled inductor current iLObtaining; the charging voltage error value DeltauoFrom a reference value u of the charging voltage of the power batteryrefSubtracting the sampled charging voltage uoThus obtaining the product.
4. The control system of claim 3, wherein the method for calculating the PWM output duty cycle d according to the two error values comprises: the inductanceFlow error value Δ iLMultiplying the current gain K to obtain a duty ratio component d 1; charging voltage error value delta uoObtaining a duty ratio component d2 through a PI controller; and adding the duty ratio components d1 and d2 to obtain a duty ratio d, wherein the amplitude limit of d is between 0 and 1.
5. The control system of claim 4, wherein the controller multiplies the duty ratio d by a count value corresponding to the current PWM cycle and performs rounding to obtain a corresponding CMP value, and sends the CMP value to a register of a PWM module in the DSP.
6. The control system of claim 5, wherein the PWM module in the DSP triggers two interrupts in one switching cycle, and after the interrupts are entered, the controller calls a voltage and current sampling program to obtain real-time voltage and current data, and then transmits the corresponding data to the algorithm program.
7. The control system of claim 2, wherein the charging current is ioWhen the measurement cannot be carried out, equivalent replacement is carried out by using the capacitance C value, and the following results are obtained:
8. the control system of the DC-DC converter according to claim 1, wherein the PWM rectification circuit comprises two groups of bridge arms consisting of four switching tubes, and the PWM rectification circuit works in a bipolar modulation state to rectify the single-phase power frequency grid voltage into a direct current high voltage to be transmitted to the DC-DC conversion circuit.
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| CN201910840691.9A CN110601571A (en) | 2019-09-06 | 2019-09-06 | Control method of DC-DC converter |
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| CN201910840691.9A CN110601571A (en) | 2019-09-06 | 2019-09-06 | Control method of DC-DC converter |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113541470A (en) * | 2021-06-21 | 2021-10-22 | 深圳市禾望科技有限公司 | DC/DC converter, control method thereof and photovoltaic power generation system |
| CN113890198A (en) * | 2021-09-09 | 2022-01-04 | 广东福德电子有限公司 | Inductance coil charge-discharge source based on direct current voltage reduction and output current control |
| CN113904396A (en) * | 2021-06-29 | 2022-01-07 | 苏州浪潮智能科技有限公司 | Method, system and apparatus for regulating charging current ripple of backup battery unit |
| CN113904564A (en) * | 2021-09-09 | 2022-01-07 | 广东福德电子有限公司 | Inductance coil charge-discharge power supply |
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| CN203398988U (en) * | 2013-05-14 | 2014-01-15 | 上海交通大学 | Improved outer loop control direct-current converter |
| CN104184325A (en) * | 2014-08-07 | 2014-12-03 | 哈尔滨工程大学 | Rapid dynamic compensation control apparatus and control method of voltage control type DC/DC converter |
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2019
- 2019-09-06 CN CN201910840691.9A patent/CN110601571A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN203398988U (en) * | 2013-05-14 | 2014-01-15 | 上海交通大学 | Improved outer loop control direct-current converter |
| CN104184325A (en) * | 2014-08-07 | 2014-12-03 | 哈尔滨工程大学 | Rapid dynamic compensation control apparatus and control method of voltage control type DC/DC converter |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113541470A (en) * | 2021-06-21 | 2021-10-22 | 深圳市禾望科技有限公司 | DC/DC converter, control method thereof and photovoltaic power generation system |
| CN113541470B (en) * | 2021-06-21 | 2023-02-28 | 深圳市禾望科技有限公司 | DC/DC converter, control method thereof and photovoltaic power generation system |
| CN113904396A (en) * | 2021-06-29 | 2022-01-07 | 苏州浪潮智能科技有限公司 | Method, system and apparatus for regulating charging current ripple of backup battery unit |
| CN113904396B (en) * | 2021-06-29 | 2023-08-15 | 苏州浪潮智能科技有限公司 | Method, system and device for adjusting charging current ripple of backup battery unit |
| CN113890198A (en) * | 2021-09-09 | 2022-01-04 | 广东福德电子有限公司 | Inductance coil charge-discharge source based on direct current voltage reduction and output current control |
| CN113904564A (en) * | 2021-09-09 | 2022-01-07 | 广东福德电子有限公司 | Inductance coil charge-discharge power supply |
| CN113890198B (en) * | 2021-09-09 | 2023-06-20 | 广东福德电子有限公司 | Inductance coil charging and discharging source based on direct current voltage reduction and output current control |
| CN113904564B (en) * | 2021-09-09 | 2023-09-22 | 广东福德电子有限公司 | Inductance coil charging and discharging power supply |
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Application publication date: 20191220 |