DE10151153A1 - Device for charging batteries for electric vehicles has converter containing inverter for producing a.c. voltage from step-up device's D.C. output and rectifier coupled via transformer - Google Patents

Abstract

The device has a controlled step-up device (1) for producing a direct voltage from a single or multi-phase alternating voltage lower than the direct voltage and a converter containing an inverter (10) for producing an alternating voltage from the step-up device and a rectifier (11) that are coupled together via a transformer (12).

Description

The invention relates to a device for charging batteries for Electric vehicles, in particular for fast charging batteries for Passenger cars, EV and NGV (Electric Vehicle and Neighborhood Electric Vehicle).

The batteries of the well-known electric vehicles are equipped with chargers charged, which are connected to a three-phase or alternating current network. The known chargers for electric vehicles either allow a controlled one Output voltage or a controlled output current operation, wherein Output voltage and current to the respective state of charge of the to be charged Battery is adjusted.

The regulation of output voltage and current takes place in the known Chargers with power semiconductors that have a relatively high power loss. Therefore, massive cooling is required, which u. a. Caused noise.

Since the chargers are not only operated at special charging stations, For example, gas stations, but also at home in the garage should be aimed at a compact and lightweight structure. The use of the Chargers must also be possible outside of enclosed spaces, so that the Chargers from external influences, such as weather, low and high Protect temperatures and moisture.

The well-known chargers have protection against external influences Protective hoods. The disadvantage is that the heat due to the relatively high It is difficult to dissipate power loss through the protective hood. in the Otherwise, the protective hoods of the known chargers often fail as splashproof.

The chargers are not only against splash water, but also in front of one Protect condensation from a drop in temperature. A Condensation can form with the protective hoods of the well-known chargers but cannot be avoided with certainty.

An important requirement for the chargers is galvanic isolation between three-phase or alternating current network on the one hand and vehicle battery on the other hand. Transformers are generally used for electrical isolation Use. The use of a transformer should, however, the dimensions and do not significantly increase the weight of the charger.

The invention has for its object a device for loading To create batteries for electric vehicles that stand out through a compact Structure and universal applicability.

This object is achieved with the features of claims 1 and 10. Advantageous embodiments are the subject of the dependent claims.

The circuit of the charging device comprises two components, namely one controlled boost converter and one downstream of the boost converter Inverter. The controlled step-up converter generates a DC voltage from a single or multi-phase, especially three-phase AC voltage, the smaller than the DC voltage is. Such step-up converters as such belong to the State of the art. They are also called step-up converters. The The controlled step-up converter can be controlled with a control circuit done in a known manner.

The converter has an inverter for generating an AC voltage from the DC voltage of the step-up converter and a rectifier Generation of a DC voltage from the AC voltage of the inverter on. For electrical isolation, the inverters and rectifiers are connected via one preferably coupled ferrite transformer. The transformer for coupling of inverters and rectifiers need only have a low output. Also the dimensions are small.

The combination of controlled step-up converter and converter allows both a controlled output voltage as well as a controlled one Output current operation. Because the slope function of the output voltage (Battery charging voltage) only taken over by the controlled step-up converter a very low-loss converter is possible. The Converter delivers an almost perfect DC voltage with minimal Harmonic load, while the step-up converter has a cosine φ close to 1 for Current and voltage allowed in the entrance. Here is a very low one Power-to-weight ratio possible, which results in the compact structure of the Charger results.

In a preferred embodiment of the loading device is in Boost converter with an input filter to avoid mains interference upstream of a single or multi-phase series choke. The three-phase Series throttle stands out in a particularly preferred embodiment by a low power loss with small dimensions. Preferably is an inverter with an output filter for smoothing the DC voltage Series choke and a smoothing capacitor. advantageously, the output filter has overvoltage protection.

The step-up converter is preferably in a three-phase bridge circuit with IGBTs (Insulated Gate Bipolar Transistor) designed as a power semiconductor. In principle, however, other power semiconductors can be used for input and Turning off the currents can be used.

The inverter of the converter preferably has two series connected IGBT's and two capacitors connected in series, the Series connection of the IGBTs in parallel with the series connection of the capacitors is switched. The rectifier of the converter is preferably known Bridge circuit made of diodes.

In addition to the special circuit technology, the compact design of the Charging device by dividing the housing into two housing parts possible, the one housing part can be flowed through by cooling air and the other housing part is sealed off from the environment, preferably is hermetically sealed. The housing part through which cooling air can flow takes the components of the charging device which generate a higher power loss, in particular the step-up converter and the converter with the power semiconductors on, while the sealed off from the environment the one lower power-generating components, such as the Control circuit that encloses the control panel etc.

In which the components with the higher power dissipation Housing part is made use of a "chimney effect". In the lower one Half of the housing part is an air inlet and in the upper half of the Part of the housing provided an air outlet for the cooling air. The cooling air can thus Enter the housing from below and exit again from above. Preferably are the components with the highest power dissipation, in particular with the power semiconductors, in the lower half of the housing. Due to the Heating rises the cooling air in the housing, so that a cooling air flow established. This is preferably supported by one or more fans. The fans are preferably located at the air outlet, where a relatively large amount There is space in the housing.

To support the chimney effect, cooling air should flow through it Housing part should be as flat as possible in the manner of a shaft. Thereby is avoided that the rising and cooling air in the housing falls off again.

In a further preferred embodiment, the housing is the Charger designed for wall mounting. To the housing also in To be able to set up outdoors, the housing plates are screwed together preferably closed with additional covers that only with Special tools or keys can be removed. In this way the loading device is largely against disassembly. or theft protected. In addition, there is also the possibility of operating the loading device via a debt collection machine that counteracts the device for a certain period of time Payment or cashless activated.

A particularly preferred embodiment of the charging device has a device for pressure relief, which is a flow connection between the closed housing part from the environment and the open Housing part when excess pressure builds up in the closed housing part manufactures. In the event that it is in the closed housing part Should arcing occur, the hot gases can escape from the closed housing part through the flow connection via the open Housing part can be safely discharged to the outside.

In a preferred embodiment, the device has pressure relief a passage in the partition between the two housing parts, wherein the passage is tightly closed by a closure member that the passage only opens when a certain overpressure is exceeded. Conveniently, is the closure part a detachable flap or the like from the partition.

A strong cooling of the housing has a volume reduction in the Air contained in the housing. Due to the volume reduction of the Air is absorbed in the housing part which is sealed off from the surroundings Vacuum generated so that condensation can form. The Condensation is formed in a particularly preferred embodiment from a device for adjusting the water vapor concentration between the two housing parts prevented. The device preferably has one Reverse osmosis membrane on which a drop in temperature Pressure equalization between the two housing parts is established.

Repair work is another particularly preferred Embodiment facilitated by a two-part housing that the Makes components accessible from several sides.

The following is an embodiment of the device for loading Batteries for electric vehicles explained in more detail with reference to the figures.

Show it:

Fig. 1 shows the circuit diagram with the main components of the battery loading device,

Fig. 2, the loading device in a top view,

Fig. 3, the charging device from the view of the arrow I of Fig. 1,

Fig. 4 is a perspective view of the housing lower part in plan view,

Fig. 5 is a perspective view of the housing lower part in plan view, with individual components are not shown,

Fig. 6, the housing upper part in the bottom view,

Fig. 7 shows the three-phase choke of the input filter of the circuit of the charging device in a sectional view and

Fig. 8 shows a section through the choke of Fig. 7.

Fig. 1 shows the essential components of the circuit of the device for charging batteries for electric vehicles, in particular passenger cars. The essential components of the circuit are a controlled step-up converter 1 (step-up converter) and a resonance converter 2 connected downstream of the step-up converter.

The controlled step-up converter is designed in a three-phase bridge circuit with IGBTs (Insulated Gate Bipolar Transistor) 3 as power semiconductors. Two IGBTs are connected in series, with three series connections of the IGBTs being connected in parallel. To protect against overvoltage, a free-wheeling diode 4 is connected in parallel in opposite directions to each IGBT 3 . The step-up converter 1 is controlled by a central control circuit 5 in such a way that it generates a variable DC voltage from a fixed three-phase AC voltage (L ₁ , L ₂ , L ₃ ) which is greater than the supply voltage (mains voltage). To smooth the pulsating DC voltage, the step-up converter 1 has a voltage intermediate circuit 28 which consists of two balancing resistors 6 and two intermediate circuit capacitors 7 .

An input filter 8 with a three-phase series choke 9 is connected upstream of the step-up converter 1 .

The resonance converter 2 has an inverter 10 and a rectifier 11 . The inverter 10 converts the DC voltage of the step-up converter 1 into an AC voltage, while the rectifier 11 again generates a DC voltage from the AC voltage of the inverter 10 . For electrical isolation, inverters and rectifiers 10 , 11 are coupled to a ferrite transformer 12 . The resonance converter 2 is controlled by the control circuit 5 . The converter 2 is operated at a clock frequency> 40 kHz.

The single-phase inverter 10 of the converter 2 has two IGBTs 13 connected in series with free-wheeling diodes 25 and two capacitors 14 connected in series, the series connection of the IGBTs being connected in parallel with the series connection of the capacitors. The rectifier 11 is designed in a bridge circuit with diodes 26 . The two input connections of the transformer 12 are each connected to the center points of the series connection of the capacitors 14 or IGBTs 13 , while the output connections of the transformer are connected to the center points of the series connection of the diode 26 .

An output filter 15 is connected downstream of the resonance converter 2 . To smooth the pulsating DC voltage, the output filter has a series choke 16 and a smoothing capacitor 17 . In addition, the output filter 15 has an overvoltage protection 18 , which has a power semiconductor 19 , for example a triac, and a resistor 20 and a diode 27 as reverse polarity protection. The overvoltage protection reduces the output voltage in case of need abruptly to 0. At the output of the output filter 15 an output voltage (charge voltage) is up to 500 V DC at (15 kW).

The controlled step-up converter 1 in connection with the resonance converter 2 allows both the setting of a constant output voltage (charging voltage) with regulated output current (charging current) and the setting of a constant charging current with regulated output voltage.

In addition to the above components, the charging device also has a control device 21 for communication between the control circuit 5 of the charging device and the battery management of the electric vehicle. The control device 21 communicates with the control circuit 5 via optocouplers 22 . The charging device is operated via a control panel 23 with a keyboard, the functions of the charging device being shown on a display 24 . A power supply 29 takes over the power supply of the charging device. Alternatively, the battery management can be integrated in the control device.

The components of the charging device accommodate a housing 40 which is intended for wall mounting. The housing 40 has a vertical rear wall 41 in the position of use, a front wall 42 and a horizontal base plate 43 and cover plate 44 as well as side walls 45 , 46 which are made of sheet metal. It consists of a lower housing part 47 and a hinged upper housing part 48 which sits tightly on the lower housing part 47 with an attached pressure and EMC seal.

A socket 49 is provided in the center of the base plate 43 of the housing 1 for connecting a connecting cable 50 with which the charging device is connected to the electric vehicle. Also located on the underside of the housing is the outlet for the mains cable 51 for connecting the charging device to a three-phase network, which can be pulled around during installation and inserted and screwed in with the cable installed.

The connecting cable 50 has at one end a housing-side plug 52 , which can be inserted into the socket 49 , and at its other end a vehicle-side plug 53 , which can be inserted into a socket, not shown, of the vehicle. The vehicle-side connector 53 has a locking mechanism 54 with which the connector can be locked firmly in the socket of the vehicle. The locking takes place by pivoting the lever 55 .

On one side wall 46 of the lower housing part 47 , a holder 56 is provided, in which the plug can be locked in the park position when the charging device is not in operation. The holder 56 for the plug 53 is a socket which corresponds to the socket of the vehicle.

The control panel 23 with the keyboard and the display 24 ( FIG. 1) are located on the front wall 42 of the housing 1 .

FIGS. 4 and 5 show a plan view of the lower housing part 47, and Fig. 6 shows a bottom view of the upper housing part 48. The housing 1 is separated by a partition 57 in the lower housing part 47 into a first housing part 58 and a second housing part 59 . The first housing part 58 is enclosed by the partition 57 and the side walls 45 and 46 and the rear wall 41 of the housing, while the second housing part 59 is enclosed by the partition 57 and the front wall 42 and the side walls 45 , 46 of the housing.

The first housing part 58 accommodates the components of the charging device which generate a higher power loss. These components include in particular the step-up converter 1 and the resonance converter 2 with the power semiconductors. In contrast, the second housing part 59 accommodates the components of the charging device which generate less power loss, which include, for example, the control panel 23 with the keyboard and the display 24 . The individual components are only hinted at in the figures. The only decisive factor is the arrangement of the components depending on the power loss in the two housing parts.

Air inlet openings 60 are located on the bottom plate 43 and the side walls 45 , 46 in the lower half of the first housing part 58 . Air outlet openings 61 are located on the cover plate 44 and the side walls 45 , 46 in the upper half of the first housing part 58 . Cooling air flows through the first housing part 47 , which enters the housing from below through the air inlet openings 60 and flows out of the housing from the air outlet openings 63 from above. This air flow is due to the fact that the air that heats up due to the power loss of the components rises. This chimney effect is reinforced by the fact that the components that generate the highest power loss are arranged on the housing base. To support the air flow, there is a fan 62 on the upper housing sides, which is covered with a removable air grill 63 .

The second housing part 59 , which receives the components that generate less loss energy, is hermetically sealed against the open first housing part 58 via the partition 57 . The partition extends essentially half the height of the lower housing part 4 R. It also serves to receive and fasten the individual components in the two housing parts.

To relieve pressure, the charging device has a device 64 which establishes a flow connection between the first and second housing parts 58 , 59 when an overpressure builds up in the second housing part 59, which is sealed off from the environment. This can be the case, for example, in the event of arcing. The device 64 for pressure relief has a passage 65 in the form of two openings 66 in a projecting part 67 of the partition 57 . The two openings 66 are each sealed with a thin sheet metal flap 68 . The connection between the partition wall 57 and the sheet metal plates 68 is such that the sheet metal plates come loose in the second housing part 59 at a slight overpressure, so that the hot gases from the first housing part 59 via the openings 68 in the partition wall 57 into the second housing part 58 and can flow to the outside via its air inlet and outlet openings 60 , 61 . Since the device 64 for pressure relief is located in the lower half of the lower housing part 47 , in which the components, in particular metal parts, are arranged, which have a particularly large heat storage capacity, air with a relatively small amount is generated via the air inlet and outlet openings during arcing Dissipated temperature. The hot gases: can cool down inside the housing on the components with the particularly high heat storage capacity, which means particularly good personal protection even in the event of an unlikely but never completely impossible electrical defect.

In order to avoid condensation in the housing 1 in the event of a sharp drop in temperature, a device 69 for equalizing the water vapor concentration in the two housing parts 58 , 59 is provided. The device 69 comprises a passage 70 in the form of bores 71 in the partition 57 , which is closed with a reverse osmosis filter which cannot be seen in the perspective view. On the one hand, the reduction in volume of the air enclosed in the second housing part 59 is compensated for in the event of a drop in temperature via the reverse osmosis filter, on the other hand, water vapor can escape to the outside in the opposite direction, so that condensation is avoided. The reverse osmosis filter is permeable to air and water vapor in both directions, namely from the closed second housing part 59 into the open first housing part 58 and vice versa.

The upper housing part 52 accommodates a plurality of smoothing capacitors 71 , which are connected in series and in parallel by means of busbars 72 . The smoothing capacitors 71 keep the ripple of the charging current small, so that the vehicle battery to be charged and the motors of the fans are protected. In addition to the capacitors 71 , the components 73 that generate a lower power loss are arranged in the upper part of the housing together with a further fan 74 , which circulates the air in the so-called clean room.

The three-phase series choke 9 in the input stage 8 for limiting the network perturbations ( FIG. 1) is arranged below the device 64 for pressure relief in the open first housing part 58 . FIGS. 7 and 8 show the series inductor in a sectional view. For each phase, the series choke has a cylindrical shell coil body 75 with a cylindrical recess 76 , in which a cylindrical coil 77 is seated. The Cu connecting conductors 80 are each led out laterally from the coil body 75 . The coil formers consist of a soft magnetic powder material of high density and specific weight, which is integrated in plastic.

The coil form 75 of the series choke 9 are pressed next to one another, the upper coil form being covered with a cover plate 79 . The coil formers are cast together with an electrically insulating casting resin to form a firm bond. For this purpose, the coils 77 in the bobbins 75 are connected by 120 ° bores 78 , which are each on the side of a bobbin that is adjacent to the adjacent bobbin. The cover plate 78 of the upper coil former also has a bore 78 . The casting resin is poured from above through the upper bore 78 into the gap between the coil and the coil body 75 , 76 , so that the casting resin flows through the holes from one coil body to the other until all the gaps are completely filled and the coil bodies form a single 3- phase choke are cast, which envelops the coils without a gap and thus enables relatively good heat dissipation.

Because bobbins with sheets that are too strong due to eddy current losses Cause warming, are not present, the series choke has a very low power dissipation. The power loss is about a factor of 5-6 less than with conventional chokes with thin sheets. They are too Dimensions significantly smaller.

Claims (19)

1. Device for charging batteries for electric vehicles with a controlled step-up converter ( 1 ) for generating a DC voltage from a single or multi-phase AC voltage, which is smaller than the DC voltage, and a converter ( 2 ) connected downstream of the step-up converter; which has a single-phase inverter ( 10 ) for generating an AC voltage from the DC voltage of the step-up converter and a rectifier ( 11 ) for generating a DC voltage from the AC voltage of the inverter, the inverter and rectifier being coupled via a transformer ( 12 ). 2. Device according to claim 1, characterized in that the step-up converter ( 1 ) is connected upstream of an input filter ( 8 ) with a single-phase or multi-phase series choke ( 9 ), which also takes over the function of the voltage setting. 3. Device according to claim 2, characterized in that the series choke ( 9 ) is a three-phase choke which has three coil formers ( 75 ) made of soft magnetic material, each of which accommodates a coil ( 77 ), the coil formers being magnetically coupled close to one another are and are cast with casting resin to fill up a gap in all gaps between the coil and the coil body. 4. Device according to one of claims 1 to 3, characterized in that the converter ( 2 ) is followed by an output filter ( 15 ) with a series choke ( 16 ) and a smoothing capacitor ( 17 ). 5. The device according to claim 4, characterized in that the output filter ( 15 ) has an overvoltage protection ( 18 ). 6. Device according to one of claims 1-5, characterized in that the step-up converter ( 1 ) is designed in a three-phase bridge circuit with IGBTs ( 3 ) as a power semiconductor. 7. Device according to one of claims 1-6, characterized in that the inverter ( 10 ) has two series-connected IGBTs ( 13 ) and two series-connected capacitors ( 14 ), the series connection of the IGBTs in parallel with the series connection of the capacitors is switched. 8. Device according to one of claims 1-7, characterized in that the rectifier ( 11 ) is designed in a bridge circuit with diodes ( 26 ). 9. Device according to one of claims 1-8, characterized in that the transformer ( 12 ) is a ferrite transformer. 10. Device for charging batteries for electric vehicles, the housing ( 1 ) with a vertical in the use position rear wall ( 41 ) and front wall ( 42 ) and a horizontal base plate ( 43 ) and cover plate ( 44 ) and side walls ( 45 , 46 ) characterized in that the housing ( 1 ) is subdivided into a first housing part ( 58 ) through which cooling air can flow to accommodate the components that generate a higher power loss and a second housing part ( 59 ) that is sealed off from the environment to accommodate the components that generate a lower power loss , An air inlet ( 60 ) being provided in the lower half of the first housing part and an air outlet ( 61 ) for cooling air being provided in the upper half of the first housing part. 11. The device according to claim 10, characterized in that the first housing part ( 58 ) from the rear wall ( 41 ) and a partition dividing the housing into the two parts ( 57 ) and the side walls ( 45 , 46 ) is enclosed. 12. The device according to claim 11, characterized in that in the first housing part ( 58 ) at least one fan ( 62 ) is provided at the air outlet ( 61 ). 13. Device according to one of claims 10 to 12, characterized in that the second housing part ( 58 ) from the front wall. ( 42 ) and a partition ( 57 ) dividing the housing into the two parts and the side walls ( 45 , 46 ) is enclosed. 14. Device according to one of claims 10 to 13, characterized in that a device ( 64 ) for pressure relief is provided which has a flow connection between the second housing part ( 59 ) and the first. Manufactures housing part ( 58 ) when an overpressure is built up, for example as a result of arcing or a short circuit in the second housing part. 15. The apparatus according to claim 14, characterized in that the device ( 64 ) for pressure relief has a passage ( 65 ) between the first and second housing part ( 58 , 59 ), the passage of a closing part opening when a certain excess pressure is exceeded ( 68 ) is tightly closed. 16. Device according to one of claims 10 to 15, characterized in that a device ( 69 ) for lowering the water vapor concentration between the first and second housing parts ( 58 , 59 ) is provided. 17. The apparatus according to claim 16, characterized in that the device ( 69 ) for lowering the water vapor concentration has a double-acting reverse osmosis filter for pressure compensation. 18. Device according to one of claims 10-17, characterized in that air inlet openings ( 60 ) in the side walls ( 45 , 46 ) and in the bottom part ( 41 ) of the lower half of the first housing part ( 58 ) and air outlet openings ( 61 ) in the side walls ( 45 , 46 ) and the cover part ( 44 ) of the upper half of the first housing part ( 58 ) are provided. 19. Device according to one of claims 10-18, characterized in that the housing ( 1 ) has a lower housing part ( 47 ) on which a housing upper part ( 48 ) is sealingly placed, a partition ( 57 ) severing the lower housing part.