CN109557356B - Current sampling circuit of isolated electric energy converter - Google Patents
Current sampling circuit of isolated electric energy converter Download PDFInfo
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- CN109557356B CN109557356B CN201811374537.9A CN201811374537A CN109557356B CN 109557356 B CN109557356 B CN 109557356B CN 201811374537 A CN201811374537 A CN 201811374537A CN 109557356 B CN109557356 B CN 109557356B
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- G01R19/0092—Arrangements for measuring currents or voltages or for indicating presence or sign thereof measuring current only
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Abstract
The invention discloses a current sampling circuit of an isolated electric energy converter, which comprises an isolated electric energy converter and a current sampling circuit, the primary winding of the isolation transformer is connected with a primary circuit in parallel, the secondary winding of the isolation transformer is connected with a secondary circuit in parallel, the current sampling circuit comprises a coupling inductor, an auxiliary winding and a sampling capacitor, wherein a primary winding of the coupling inductor is connected in series between the primary circuit and a primary winding of the isolation transformer, the secondary winding of the coupling inductor is connected with the sampling capacitor in parallel through a resistor, the auxiliary winding is coupled with the secondary side of the isolation transformer, the auxiliary winding is connected with the sampling capacitor in parallel through a resistor, and the coupling inductor and the capacitor are used for sampling the secondary side current of the isolated electric energy converter, so that the loss of a circuit is reduced, and the defect of resistance sampling is avoided.
Description
Technical Field
The present invention relates to the field of isolated power converters, and more particularly, to a secondary current sampling circuit for an isolated power converter.
Background
With the rapid development of the switching power supply, the industrial world has higher requirements on efficiency and power density, and brick power supplies with fixed sizes are formed, such as 1/4 brick module power supplies, 1/2 brick module power supplies, full brick module power supplies and the like. In these power supply modules, it is often necessary to monitor the output current to obtain the current operating state of the power supply in real time. Because the traditional current sampling mode needs a larger area for placing a sampling resistor or a current transformer and has certain loss, the size of the power supply is very small, the requirements of users on power and power density are continuously improved along with the development of the power supply technology, and the requirements are stricter particularly in occasions such as a server, a processor and the like. For some occasions with higher requirements on efficiency and volume, a current sampling mode needs to be improved, and the working efficiency of the converter is improved.
Disclosure of Invention
The invention is based on the idea that a sampling circuit without a sampling resistor is realized, so that adverse effects caused by resistance sampling can be realized, and the circuit efficiency is improved.
The current sampling circuit of the isolation type electric energy converter comprises the isolation type electric energy converter, wherein the isolation type electric energy converter at least comprises an isolation transformer, a primary winding of the isolation transformer is connected with the primary circuit in parallel, a secondary winding of the isolation transformer is connected with a secondary circuit in parallel, the current sampling circuit comprises a coupling inductor, an auxiliary winding and a sampling capacitor, the primary winding of the coupling inductor is connected between the primary circuit and the primary winding of the isolation transformer in series, the secondary winding of the coupling inductor is connected with the sampling capacitor in parallel through a first resistor, the auxiliary winding is coupled with the secondary side of the isolation transformer, and the auxiliary winding is connected with the sampling capacitor in parallel through a second resistor.
The turn ratio of the secondary winding to the primary winding of the coupling inductor
Inductance L1 of primary winding of the coupling inductor and turn ratio of secondary winding to primary winding of the isolation transformer
The excitation inductance L2 of the isolation transformer, the resistance r1 of the first resistor and the resistance r2 of the second resistor are required to satisfy the following conditions:
the voltage at the two ends of the sampling capacitor is in proportional relation with the output current of the secondary winding of the isolation transformer.
The primary side circuit comprises an input voltage, a first switch and a second switch, wherein a bridge arm is formed by connecting the first switch and the second switch in series, the positive end of the input voltage is connected with the first switch, the negative end of the input voltage is connected with the second switch, the midpoint of the bridge arm is connected with one end of a primary side winding of a coupling inductor, the other end of the primary side winding of the coupling inductor is connected with one end of a primary side winding of an isolation transformer, the other end of the primary side winding of the isolation transformer is connected with a first capacitor, the other end of the first capacitor is connected with the negative end of the input voltage, and the secondary side circuit is a full-wave rectification circuit.
The sampling resistor has the beneficial effects that a large-volume sampling resistor is omitted, and the loss caused by the sampling resistor is avoided.
In order to make the aforementioned and other features and advantages of the invention more comprehensible, embodiments accompanied with figures are described in detail below.
Drawings
FIG. 1 is a schematic diagram of a current sampling circuit of an isolated power converter of the present invention.
Fig. 2 is a schematic circuit diagram of the current sampling circuit in fig. 1 applied to a resonant isolated converter.
Detailed Description
In order to make the purpose and technical solution of the embodiments of the present invention clearer, the technical solution of the embodiments of the present invention will be clearly and completely described below with reference to the drawings of the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention without any inventive step, are within the scope of protection of the invention.
As shown in fig. 1, the isolated power converter 10 of the present invention includes an isolation transformer T2, the isolation transformer T2 includes a primary winding N3 and a secondary winding N5, the primary winding N3 of the isolation transformer T2 is connected in parallel to the primary circuit 11, and the secondary winding N5 of the isolation transformer T2 is connected in parallel to the current sampling circuit of the secondary circuit 12. The isolated power converter 10 further comprises a current sampling circuit 13, wherein the current sampling circuit 13 comprises an auxiliary winding N4, the auxiliary winding N4 is coupled with an isolation transformer T2, the end with the same name is the same as a secondary winding N5 of the isolation transformer T2, the auxiliary winding N4 is connected in parallel with two ends of a sampling capacitor C1 after being connected in series with a resistor R2, the current sampling circuit 13 further comprises a coupling inductor T1, the coupling inductor comprises a primary winding N1 and a secondary winding N2, the primary winding N1 is connected in series between a primary winding N3 of the isolation transformer T2 and a primary circuit 11, and the secondary winding N2 is connected in parallel with the sampling capacitor C1 after being connected in series with a resistor R1.
T1 is a coupling inductor, the number of turns of the primary winding N1 is N1 turns, the number of turns of the secondary winding N2 is N2 turns, the inductance of the primary winding N1 is known as L1, T2 is a transformer, the inductance of the excitation inductor is L2, the number of turns of the primary winding N3 is N3, the number of turns of the secondary winding N4 is N4, the impedance of the first resistor R1 is R1, the impedance of the second resistor R2 is R2, and the following relationships are satisfied:
the value of the voltage Vc on the sampling capacitor C1 can be equivalent to the value of the current I4 of the secondary winding N5 multiplied by a proportionality coefficient in real time, so that the value of the current I4 of the secondary winding N5 can be detected by detecting the value of the voltage Vc on the C1.
Fig. 2 is a schematic circuit diagram of the current sampling circuit in fig. 1 applied to a resonant isolated converter, and as shown in the figure, the isolated power converter of the present embodiment employs a half-bridge LLC series resonant converter, but the present invention is not limited thereto. The input voltage Vin is connected to a bridge arm formed by connecting switches S1 and S2 in series, the positive end of the Vin is connected with an upper switch S1, the negative end of the Vin is connected with a lower switch S2, the midpoint of the bridge arm is connected with one end of a primary winding N1 of a coupling inductor T1, the other end of a primary winding N1 of the coupling inductor T1 is connected with one end of a primary winding N3 of an isolation transformer T2, the other end of a primary winding N3 of the isolation transformer T2 is connected with a capacitor C2, and the other end of C2 is connected with the negative end of the Vin. The secondary side of the isolation transformer T2 adopts a full-wave rectification circuit with a center tap, two ends of a secondary winding N5 of the isolation transformer T2 are respectively connected with one ends of switches D1 and D2, the other ends of the switches D1 and D2 are mutually connected and are connected to the negative end of an output capacitor Co and the ground, and the center tap of the secondary winding N5 of the T1 is connected to the positive end of the Co. However, the secondary circuit of the present invention is not limited to this, and for example, a half-wave rectifier circuit, a synchronous rectifier circuit, or the like may be used as the secondary circuit.
In this embodiment, the secondary winding of the coupling inductor T1 is connected in parallel with the sampling capacitor C1 through a resistor R1, the isolation transformer T2 further includes an auxiliary winding N4, and two ends of the auxiliary winding N4 are connected in parallel with the sampling capacitor C1 through a resistor R2.
As shown in fig. 2, the couplerTurn ratio of the combined inductance T1
Primary side inductance L1 and the turn ratio of isolation transformer T2
The exciting inductance L2 needs to satisfy the following condition:
the value of the voltage Vc at C1 can be equivalent to the current value I4 of the secondary winding N5 multiplied by a proportionality coefficient in real time, so that the current value I4 of the secondary winding N5 can be detected by detecting the value of the voltage Vc at C1.
Although the present invention has been described with reference to the above embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention.
Claims (3)
1. A current sampling circuit of an isolation type electric energy converter comprises the isolation type electric energy converter, the isolation type electric energy converter at least comprises an isolation transformer, a primary winding of the isolation transformer is connected with a primary circuit in parallel, a secondary winding of the isolation transformer is connected with a secondary circuit in parallel, the current sampling circuit is characterized by comprising a coupling inductor, an auxiliary winding and a sampling capacitor, the primary winding of the coupling inductor is connected between the primary circuit and the primary winding of the isolation transformer in series, the secondary winding of the coupling inductor is connected with a first resistor in series and then connected with the sampling capacitor in parallel, the auxiliary winding is coupled with the secondary side of the isolation transformer, the auxiliary winding is connected with a second resistor in series and then connected with the sampling capacitor in parallel,
the turn ratio of the secondary winding to the primary winding of the coupling inductor
Inductance L1 of primary winding of the coupling inductor and turn ratio of secondary winding to primary winding of the isolation transformer
The excitation inductance L2 of the isolation transformer, the resistance r1 of the first resistor and the resistance r2 of the second resistor are required to satisfy the following conditions:
2. the isolated power converter current sampling circuit of claim 1, wherein the voltage across the sampling capacitor is proportional to the output current of the secondary winding of the isolation transformer, and the output current of the secondary winding of the isolation transformer is calculated by sampling the voltage across the sampling capacitor.
3. The isolated power converter current sampling circuit of claim 2, wherein said primary circuit comprises a first switch and a second switch, said first and second switches are connected in series to form a bridge arm, said first switch is connected to a positive terminal of an input voltage, said second switch is connected to a negative terminal of the input voltage, a midpoint of said bridge arm is connected to one end of said primary winding of said coupled inductor, another end of said primary winding of said coupled inductor is connected to one end of said primary winding of said isolation transformer, another end of said primary winding of said isolation transformer is connected to a first capacitor, another end of said first capacitor is connected to a negative terminal of the input voltage, and said secondary circuit is a full-wave rectifier circuit.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201811374537.9A CN109557356B (en) | 2018-11-19 | 2018-11-19 | Current sampling circuit of isolated electric energy converter |
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| CN201811374537.9A CN109557356B (en) | 2018-11-19 | 2018-11-19 | Current sampling circuit of isolated electric energy converter |
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| CN109557356B true CN109557356B (en) | 2021-06-11 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110045174A (en) * | 2019-05-24 | 2019-07-23 | 南京酷科电子科技有限公司 | A kind of current sampling circuit |
| CN113411071A (en) * | 2021-05-31 | 2021-09-17 | 中国工程物理研究院流体物理研究所 | LTD module and circuit for improving discharge synchronism of internal branch circuit thereof |
| CN117907877B (en) * | 2024-03-20 | 2024-06-11 | 江苏展芯半导体技术股份有限公司 | Current detection circuit of isolated converter |
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| CN102590580A (en) * | 2012-01-10 | 2012-07-18 | 南京航空航天大学 | Circuit and method for sampling excitation inductance current of integrated transformer |
| CN103887984A (en) * | 2014-03-28 | 2014-06-25 | 矽力杰半导体技术(杭州)有限公司 | Isolating converter and switching power supply comprising same |
| CN204347112U (en) * | 2015-01-15 | 2015-05-20 | 天津军星管业集团有限公司 | A kind of current detection circuit being applicable to the current transformer of digital power |
| CN105099203A (en) * | 2015-07-24 | 2015-11-25 | 矽力杰半导体技术(杭州)有限公司 | Voltage sampling control circuit, voltage sampling control method and isolated converter |
| CN105226916A (en) * | 2014-06-25 | 2016-01-06 | 台达电子企业管理（上海）有限公司 | The current sample method of isolated power converters and sampling apparatus |
| CN106771489A (en) * | 2016-12-22 | 2017-05-31 | 江苏由甲申田新能源科技有限公司 | Isolated form low-voltage, high-current DC DC converters method for detecting output current and device |
| CN206505117U (en) * | 2016-12-22 | 2017-09-19 | 江苏由甲申田新能源科技有限公司 | Isolated form low-voltage, high-current DC DC converter detecting device for output current |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10097243B2 (en) * | 2013-03-15 | 2018-10-09 | David Schie | Isolator |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102590580A (en) * | 2012-01-10 | 2012-07-18 | 南京航空航天大学 | Circuit and method for sampling excitation inductance current of integrated transformer |
| CN103887984A (en) * | 2014-03-28 | 2014-06-25 | 矽力杰半导体技术(杭州)有限公司 | Isolating converter and switching power supply comprising same |
| CN105226916A (en) * | 2014-06-25 | 2016-01-06 | 台达电子企业管理（上海）有限公司 | The current sample method of isolated power converters and sampling apparatus |
| CN204347112U (en) * | 2015-01-15 | 2015-05-20 | 天津军星管业集团有限公司 | A kind of current detection circuit being applicable to the current transformer of digital power |
| CN105099203A (en) * | 2015-07-24 | 2015-11-25 | 矽力杰半导体技术(杭州)有限公司 | Voltage sampling control circuit, voltage sampling control method and isolated converter |
| CN106771489A (en) * | 2016-12-22 | 2017-05-31 | 江苏由甲申田新能源科技有限公司 | Isolated form low-voltage, high-current DC DC converters method for detecting output current and device |
| CN206505117U (en) * | 2016-12-22 | 2017-09-19 | 江苏由甲申田新能源科技有限公司 | Isolated form low-voltage, high-current DC DC converter detecting device for output current |
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Effective date of registration: 20211130 Address after: 335003 No. 19, wanbaozhi Road, high tech Industrial Development Zone, Yingtan City, Jiangxi Province Patentee after: JIANGXI BOLANDE ENERGY TECHNOLOGY CO.,LTD. Address before: 210000 floor 12, building a, Baixia gaoxinyuan cloud computing innovation base, No. 6, Yongzhi Road, Qinhuai District, Nanjing, Jiangsu Patentee before: NANJING BOLANDE POWER TECHNOLOGY DEVELOPMENT Co.,Ltd. |
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