CN113489298A - Pre-charging circuit applied to alternating current-direct current bidirectional inverter power supply module - Google Patents
Pre-charging circuit applied to alternating current-direct current bidirectional inverter power supply module Download PDFInfo
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- CN113489298A CN113489298A CN202110963329.8A CN202110963329A CN113489298A CN 113489298 A CN113489298 A CN 113489298A CN 202110963329 A CN202110963329 A CN 202110963329A CN 113489298 A CN113489298 A CN 113489298A
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- 239000003990 capacitor Substances 0.000 claims abstract description 52
- 238000010586 diagram Methods 0.000 description 4
- 230000000670 limiting effect Effects 0.000 description 4
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- 238000006243 chemical reaction Methods 0.000 description 3
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- 230000002159 abnormal effect Effects 0.000 description 1
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- 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
- H02M1/32—Means for protecting converters other than automatic disconnection
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- 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
- H02M7/66—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with possibility of reversal
Abstract
The invention relates to the field of power electronics, in particular to a pre-charging circuit applied to an alternating current-direct current bidirectional inverter power supply module, which comprises a forward pre-charging circuit, a reverse pre-charging circuit and a bypass rectifying circuit, wherein the forward pre-charging circuit meets the pre-charging requirement of a bus capacitor of the power supply module working under the conditions from DC to AC (inversion mode), and shares a group of pre-charging resistors RY with the reverse pre-charging circuit; the reverse pre-charging circuit meets the pre-charging requirement of a bus capacitor of a power supply module working in an AC-to-DC (rectification mode); the bypass rectifying circuit and the body diode of the module main circuit power switch naturally rectify to obtain the same rectified voltage. The pre-charging requirements of the inverter power supply module in different working modes are met, and the system is ensured to be powered on reliably. Because the pre-charging resistor is common, the increase of the number of additional pre-charging resistors is avoided, the utilization rate of the pre-charging resistor is improved, and the advantages of shorter charging time and smaller pre-charging loss are achieved.
Description
Technical Field
The invention relates to the field of power electronics, in particular to a pre-charging circuit applied to an alternating current-direct current bidirectional inverter power supply module.
Background
With the rapid development of power electronic technology, new power semiconductor devices are being promoted, and the requirements of different application occasions on different electric energy conversion modes are met. After the application of new energy becomes an industrial hotspot, a corresponding power electronic energy conversion mode is generated. In addition, the increasing demand for electrical energy means that electronic-to-electronic conversion devices are rapidly moving toward high voltage and high power.
The pre-charging circuit is an important component of the alternating current and direct current bidirectional inverter power supply module, and has the main function of pre-charging the bus capacitor when the system is powered on. The phenomenon that relevant components and parts are damaged by strong impact current during electrification, even the whole power module is damaged, and adverse effects on the electrification safety and reliability are avoided.
The precharge circuits and methods proposed in different power supply application fields are limited to unidirectional power flow or to applications involving lower power levels and voltage levels. The high-power bidirectional alternating current and direct current inverter power supply module cannot meet the requirements.
In view of the inapplicability that present precharge scheme exists, this patent proposes a precharge circuit who is applied to two-way alternating current-direct current invertion power module. The bus capacitor is charged through the two pre-charging loops respectively, so that the pre-charging requirements of the inverter power module in different working modes are met, and the system is ensured to be powered on reliably. In addition, the pre-charging resistor is shared by the two pre-charging loops, so that the increase of the number of additional pre-charging resistors is avoided, the utilization rate of the pre-charging resistor is well improved, and the advantages of shorter charging time and smaller pre-charging loss are achieved.
Disclosure of Invention
In order to achieve the purpose, the invention provides a pre-charging circuit applied to an alternating current-direct current bidirectional inverter power supply module, which comprises a forward pre-charging circuit and a reverse pre-charging circuit, and aims to ensure that a system is electrified safely and reliably and avoid the damage of the system caused by impact current caused by extremely high potential difference between an input end and a bus capacitor when a switch is closed.
A pre-charging circuit applied to an alternating current-direct current bidirectional inverter power supply module is divided into a forward pre-charging circuit and a reverse pre-charging circuit according to the characteristic of bidirectional power flow of the inverter power supply module, and the requirement that the inverter power supply works from DC to AC, namely an inverter mode, is met respectively; precharge requirements for operation in AC to DC, i.e., rectified mode.
When the inverter power supply module works in an inverter mode, high-voltage direct current is input, and the two input inlet wires are L and N respectively. The main direct current side circuit breaker QS1 is connected in series with the direct current input end to close the main circuit breaker, and the voltage of the point A and the point B is the input voltage. Direct current side main contactor KM1 establishes ties between main circuit breaker and bus capacitor, this moment if direct closed KM1, the input is direct to link to each other with bus capacitor, enough big generating line (mF level) electric capacity can form the capacitive short circuit in the twinkling of an eye of closed main contactor, powerful surge current (kilo ampere level) can lead to the adhesion of contactor contact, damage main contactor, in addition, very big charging current can lead to the fact the damage to bus capacitor, harm capacitance performance, shorten the life of electric capacity, thereby to entire system's equipment security, the reliability brings extremely adverse effect. Therefore, before closing the main contactor KM1, the bus capacitor is charged by the precharge circuit, so that the potential difference across the main contactor KM1 is substantially uniform.
The forward pre-charging circuit comprises a direct current input end, a main circuit breaker QS1, a main contactor KM1, a bus capacitor CBUS, a pre-charging resistor RY and a rectifier bridge D1, when the main circuit breaker QS1 is closed, the main contactor KM1 keeps an open state, power flow reaches the rectifier bridge D1 from the input end through the main circuit breaker, passes through the pre-charging resistor R after passing through D1, and finally reaches the bus capacitor CbusCharging the bus capacitor by the current limiting function of the pre-charging resistor, and charging the bus capacitor with the voltage for a predetermined timeTo be raised to equal the input voltage. That is, the voltages across the main contactor KM1 were substantially equal. Therefore, after the pre-charging is finished, the system is normally powered on, the KM1 is closed, and the potential difference between the two ends of the KM1 can be ignored, so that large impact current can not be caused, and the main contactor, the bus capacitor and a main circuit power device are protected.
When the inverter power supply module works in a reverse rectification mode, the three-phase alternating current is input into the inverter power supply module at 380VAC and 50Hz, and the input end comprises three phase lines and an N line. Three phase lines at the input end are sequentially connected with an alternating current side main breaker QS2 and an alternating current side main contactor KM2 in series, the alternating current side main contactor KM2 is connected with a main circuit after entering a module, and an alternating current side main switch KM3 is connected in the main circuit in series. The main switch KM3 is controlled to be closed and opened to cooperate with the main circuit to perform reverse rectification operation. The inverter main circuit topology adopts a three-phase diode clamp type three-level structure, and the output end of the main circuit is a bus capacitor. The input N line is connected to the bus capacitor midpoint.
When the system is powered on, an alternating current side main breaker QS2 is closed, and an alternating current side main contactor KM2 is closed. At this time, if the main switch KM3 on the ac side is closed, the power flows from the ac input end through QS2, KM2 and KM3 to the main circuit arm. At the moment, the power switch tube driving circuit on the main circuit bridge arm does not work, and the bus capacitor is charged after the power flows through the power switch tube diode to be naturally rectified. The rectified voltage of the three-phase four-wire diode is about √ 2UABVDC(UABMains line voltage), like the forward pre-charging circuit, the very high input voltage charges the large bus capacitor, which results in a strong inrush current, which may damage the main switch KM3, the main circuit power device, the bus capacitor, etc., further causing damage to the entire system, resulting in an inestimable loss.
The reverse pre-charging circuit comprises a three-phase four-wire alternating current input end, a bypass rectifying circuit, a pre-charging resistor RY and a bus capacitor, a main circuit breaker QS2 on the alternating current side, a main contactor KM2 is closed, a main switch KM3 keeps an open state, power flow enters the bypass rectifying circuit D2 from the alternating current input end, and after the power flow is naturally rectified by a three-phase four-wire rectifying bridge formed by the D2, three-phase alternating current input commercial power is converted into √ 2UABVDC. The rectified output is connected toA pre-charging resistor for increasing the voltage of the bus capacitor to √ 2U within a predetermined time by the current limiting function of the pre-charging resistorABVDC. After the pre-charging is finished, the system is normally electrified, the main relay at the alternating current side is closed, the diode of the body of the main circuit bridge arm power switch is reversely cut by the voltage of the bus capacitor, so that strong impact current cannot occur, the main switch KM3, a main circuit power device, the bus capacitor and the like are protected, and the electrifying safety and reliability of the whole system are ensured. When the main circuit of the power supply module works normally, the main circuit enters a boost mode, the voltage of the bus capacitor can be continuously increased, and at the moment, the diode of the bypass rectifying circuit is reversely cut off.
In order to reduce the number of pre-charging resistors and improve the power density of the module and the utilization rate of the pre-charging resistors, the forward pre-charging circuit and the reverse pre-charging circuit share one group of pre-charging resistors. In addition, when the inverter power module works in an AC-to-DC reverse rectification mode, the pre-charging power flow reaches the pre-charging resistor after passing through the bypass rectification circuit. And the precharge resistor is connected to the output terminal of the rectifier bridge D1 in another precharge circuit. If the rectifier bridge D1 is not provided, the AC input end passes through the reverse pre-charging loop, and a V2U is formed at the DC input endABVDC, and at this moment, the inverter power supply module does not work. To avoid such abnormal operation, a rectifier bridge is added to the forward precharge circuit to isolate the rectified voltage from the reverse precharge circuit.
The invention has the beneficial effects that: and a pre-charging scheme is provided for the high-voltage high-power alternating current and direct current bidirectional inverter power supply module. Because the current-carrying capacity of switching devices such as a relay, a contactor and the like is limited, the pre-charging circuit avoids strong impact current when the system is electrified, so that the switching equipment, the bus capacitor and main circuit components are damaged, and the safety and the reliability of the electrification of the system are ensured.
Drawings
Fig. 1 is a schematic diagram of a pre-charging circuit applied to an ac/dc bidirectional inverter power module according to the present invention.
Fig. 2 is a schematic diagram of the forward pre-charging of the pre-charging circuit applied to the ac/dc bidirectional inverter power module according to the present invention.
Fig. 3 is a schematic diagram of the reverse pre-charging of the pre-charging circuit applied to the ac/dc bidirectional inverter power module according to the present invention.
Fig. 4 is a diagram of a bypass rectification circuit in a reverse pre-charging circuit of the pre-charging circuit applied to the alternating current and direct current bidirectional inverter power supply module.
The specific implementation mode is as follows:
in order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the invention. As shown in fig. 1, since the inverter module has bidirectional power flow characteristics, a precharge circuit satisfying two operating modes is provided under the condition of sharing a set of precharge resistors.
As shown in fig. 2, when the inverter module operates in the inverter mode, the forward precharge circuit charges the bus capacitor. High-voltage direct current input, two input inlet wires are L and N respectively. The main direct current side circuit breaker QS1 is connected in series with the direct current input end to close the main circuit breaker, and the voltage of the point A and the point B is the input voltage. Direct current side main contactor KM1 establishes ties between main circuit breaker and bus capacitor, this moment if direct closed KM1, the input is direct to link to each other with bus capacitor, enough big generating line (mF level) electric capacity can form the capacitive short circuit in the twinkling of an eye of closed main contactor, powerful surge current (kilo ampere level) can lead to the adhesion of contactor contact, damage main contactor, in addition, very big charging current can lead to the fact the damage to bus capacitor, harm capacitance performance, shorten the life of electric capacity, thereby to entire system's equipment security, the reliability brings extremely adverse effect. Therefore, before closing the main contactor KM1, the bus capacitor is charged by the precharge circuit, so that the potential difference across the main contactor KM1 is substantially uniform.
In the forward pre-charging circuit, after a main breaker QS1 is closed, a main contactor KM1 keeps an open state, power flow reaches a rectifier bridge D1 from an input end through the main breaker, passes through a pre-charging resistor R after passing through D1, and finally reaches a bus capacitor CbusThe bus capacitor is charged by the current limiting action of the pre-charging resistor, and the voltage of the bus capacitor is increased to be equal to the input voltage within a specified time. That is, the voltages across the main contactor KM1 were substantially equal. Therefore, after the pre-charging is finished, the system is normally powered on, the KM1 is closed, and the potential difference between the two ends of the KM1 can be ignored, so that large impact current can not be caused, and the main contactor, the bus capacitor and a main circuit power device are protected. As shown in fig. 3, when the inverter module operates in the rectification mode, the bus capacitor is charged from the reverse direction to the precharge circuit. The three-phase alternating current input is 380VAC and 50Hz, and the input end comprises three phase lines and an N line. Three phase lines at the input end are sequentially connected with an alternating current side main breaker QS2 and an alternating current side main contactor KM2 in series, the alternating current side main contactor KM2 is connected with a main circuit after entering a module, and an alternating current side main switch KM3 is connected in the main circuit in series. The main switch KM3 is controlled to be closed and opened to cooperate with the main circuit to perform reverse rectification operation. The inverter main circuit topology adopts a three-phase diode clamp type three-level structure, and the output end of the main circuit is a bus capacitor. The input N line is connected to the bus capacitor midpoint.
When the system is powered on, an alternating current side main breaker QS2 is closed, and an alternating current side main contactor KM2 is closed. At this time, if the main switch KM3 on the ac side is closed, the power flows from the ac input end through QS2, KM2 and KM3 to the main circuit arm. At the moment, the power switch tube driving circuit on the main circuit bridge arm does not work, and the bus capacitor is charged after the power flows through the power switch tube diode to be naturally rectified. The rectified voltage of the three-phase four-wire diode is about √ 2UABVDC(UABMains line voltage), like the forward pre-charging circuit, the very high input voltage charges the large bus capacitor, which results in a strong inrush current, which may damage the main switch KM3, the main circuit power device, the bus capacitor, etc., further causing damage to the entire system, resulting in an inestimable loss.
The reverse pre-charging circuit, an alternating current side main breaker QS2 and a main contactor KM2 are closed, a main switch KM3 keeps an open state, power flow enters a bypass rectifying circuit D2 from an alternating current input end, and after natural rectification through a three-phase four-wire rectifying bridge formed by the D2, three-phase alternating current is input into commercial powerConversion to √ 2UABVDC. The rectified output is connected to a pre-charge resistor, and the voltage of the bus capacitor is increased to √ 2U within a specified time by the current limiting action of the pre-charge resistorABVDC. After the pre-charging is finished, the system is normally electrified, the main relay at the alternating current side is closed, the diode of the body of the main circuit bridge arm power switch is reversely cut by the voltage of the bus capacitor, so that strong impact current cannot occur, the main switch KM3, a main circuit power device, the bus capacitor and the like are protected, and the electrifying safety and reliability of the whole system are ensured. When the main circuit of the power supply module works normally, the main circuit enters a boost mode, the voltage of the bus capacitor can be continuously increased, and at the moment, the diode of the bypass rectifying circuit is reversely cut off.
As shown in FIG. 4, the three-phase four-wire rectifier bridge composed of DT 1-DT 6 has rectified voltage stabilized by rectified output capacitors C1 and C2, and then passed through a pre-charge resistor RY1And RY2Is a bus capacitor CBUSAnd (6) charging. When the bypass rectifier bridge is cut off, R1 and R2 provide discharge loops for the rectifier bridge output capacitors C1 and C2. And proper capacitance resistance parameters are selected, so that the charging time of the bus capacitor can be well controlled, and lower pre-charging resistance loss is ensured.
Claims (4)
1. The utility model provides a precharge circuit for alternating current-direct current two-way invertion power supply module which characterized in that, includes forward precharge circuit and reverse precharge circuit, wherein:
the forward pre-charging circuit meets the pre-charging requirement of a bus capacitor of a power module working in a DC-to-AC (inversion mode);
the reverse pre-charging circuit meets the pre-charging requirement of a bus capacitor of a power supply module working in an AC-DC (rectification mode).
2. The pre-charging circuit applied to the alternating current-direct current bidirectional inverter power supply module as claimed in claim 1, wherein the forward pre-charging circuit and the reverse pre-charging circuit share a set of pre-charging resistors RY.
3. The pre-charging circuit applied to the alternating current-direct current bidirectional inverter power supply module as claimed in claim 1, wherein the forward pre-charging circuit comprises a direct current input end, a main breaker QS1, a main contactor KM1, a bus capacitor CBUS, a pre-charging resistor RY and a rectifier bridge D1, wherein: the rectifier bridge D1 prevents the rectified voltage obtained by the reverse precharge circuit via the bypass rectifier circuit from entering the dc input side.
4. The pre-charging circuit applied to the alternating current-direct current bidirectional inverter power supply module as claimed in claim 1, wherein the reverse pre-charging circuit comprises a three-phase four-wire alternating current input end, a bypass rectifying circuit, a pre-charging resistor RY and a bus capacitor, wherein: the bypass rectifying circuit is a three-phase four-wire rectifying circuit, and naturally rectifies the three-phase four-wire rectifying circuit with a body diode of a power switch tube of the main circuit of the module to obtain the same rectifying voltage, so that the body diode is effectively and reversely cut off.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110963329.8A CN113489298A (en) | 2021-08-20 | 2021-08-20 | Pre-charging circuit applied to alternating current-direct current bidirectional inverter power supply module |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202110963329.8A CN113489298A (en) | 2021-08-20 | 2021-08-20 | Pre-charging circuit applied to alternating current-direct current bidirectional inverter power supply module |
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| US20160352252A1 (en) * | 2015-05-27 | 2016-12-01 | Sungrow Power Supply Co., Ltd. | Pre-charge circuit and photovoltaic inverter |
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| CN209881476U (en) * | 2019-05-31 | 2019-12-31 | 浙江德升新能源科技有限公司 | Pre-charging device for energy storage converter |
| CN211641853U (en) * | 2020-01-14 | 2020-10-09 | 中车资阳机车有限公司 | Double-branch pre-charging circuit of pure electric rail locomotive |
| CN212627672U (en) * | 2020-07-24 | 2021-02-26 | 苏州艾尔智科变频科技有限公司 | Capacitor pre-charging device |
| CN112671021A (en) * | 2020-12-30 | 2021-04-16 | 天津瑞能电气有限公司 | Control protection system of dual precharge |
-
2021
- 2021-08-20 CN CN202110963329.8A patent/CN113489298A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104135055A (en) * | 2014-08-08 | 2014-11-05 | 株洲南车时代电气股份有限公司 | Traction battery charger for engineering maintenance vehicle |
| US20160352252A1 (en) * | 2015-05-27 | 2016-12-01 | Sungrow Power Supply Co., Ltd. | Pre-charge circuit and photovoltaic inverter |
| CN206992699U (en) * | 2017-06-05 | 2018-02-09 | 普世通（北京）电气有限公司 | The power quality controlling device of pre-charge circuit is carried suitable for super capacitor energy-storage |
| CN209881476U (en) * | 2019-05-31 | 2019-12-31 | 浙江德升新能源科技有限公司 | Pre-charging device for energy storage converter |
| CN211641853U (en) * | 2020-01-14 | 2020-10-09 | 中车资阳机车有限公司 | Double-branch pre-charging circuit of pure electric rail locomotive |
| CN212627672U (en) * | 2020-07-24 | 2021-02-26 | 苏州艾尔智科变频科技有限公司 | Capacitor pre-charging device |
| CN112671021A (en) * | 2020-12-30 | 2021-04-16 | 天津瑞能电气有限公司 | Control protection system of dual precharge |
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