FR3021816A1 - BATTERY CHARGER FOR ELECTRIC MOTOR VEHICLE HAVING VARIABLE PASSIVE COMPENSATION MEANS AND METHOD OF CONTROLLING SUCH CHARGER - Google Patents

Abstract

Battery charger for an uninsulated type of electric or hybrid motor vehicle comprising, connected in succession, an input filter (2), a rectifier (3), an electric machine (4), an inverter (5) and a battery ( 6), fed by a three-phase power supply network (1), the charger comprising a calculation means (7) connected at input to a network type sensor, to a current sensor (8) and to a voltage sensor (9) connected between the power supply network (1) and the input filters (2), the calculation means (7) being able to control the connection of passive compensation means (11) and / or the switching contactors (10) arranged upstream of the rectifier (3) as a function of the signal received from the network type sensor and the comparison of the leakage current determined according to the voltage and current measurements to a leakage threshold value.

Description

1 Battery charger for an electric motor vehicle with variable passive compensation means and method for controlling such a charger.

The technical field of the invention is the battery chargers for an electric or hybrid motor vehicle, and more specifically, such uninsulated battery chargers. A non-isolated battery charger powered by a three-phase network is illustrated in FIG. 1. A three-phase supply network 1 connected to an input filter 2 comprising three capacitors coupled in a star can be seen, the three phases being each connected to the middle of an arm of a three-arm diode bridge forming a rectifier 3. An output of the rectifier 3 is connected to the minus terminal of the battery while the other is connected to three inductors of an electric machine 4, each inductor being connected to the middle of an arm of an inverter 5, comprising three switch arms. The outputs of the inverter 5 are connected to the battery 6. Such a charger is known from the state of the art by the document FR 2 943 188.

Figure 2 illustrates a single-phase connection of this same charger. It can be seen a single-phase power supply network 1 connected to an input filter 2 comprising three star-coupled capacitors, the three phases being each connected to the middle of an arm of a three-arm diode bridge forming a rectifier 3 One output of the rectifier 3 is connected to the minus terminal of the battery while the other is connected to three inductances of an electric machine 4, each inductor being connected to the middle of an arm of an inverter 5, comprising three switch arms. Referring to FIG. 3, it is possible to see a charger architecture powered by a three-phase network, in which the capacitive components on the high voltage potentials, as well as the filtering components, capable of generating voltage currents, have been specified. important leak. These capacitive and associated components, denoted Cf, Cmot, Cpl and Cp2, generate low-frequency leakage currents during charging.

3021816 2 These leakage currents are likely to cause significant currents of touch. In order to limit the currents of touching, this type of charger architecture is carried out to check the presence of the earth 5 by suitable electronics. Such a check is known from the state of the art, in particular in the document FR 2 976 361. However leaks are not minimized and the load can only be done on installations provided with a grounding of the transformer. network supply. Thus the charges are not made in the IT regime or on networks with no connection to earth or bad connection to the ground. Other methods known from documents FR 2 966 652 and FR 2 975 498 synthesize the methods for detecting leak currents and touch currents, as well as a presence detection circuit for the earth. The methods described in these two documents do not make it possible to minimize the leakage currents. Document FR 2 980 318 discloses another method of active compensation for continuously injecting a current into the earth through an earthing capacitance. This method does not allow transient regimes to be taken into account in a safe manner when inadvertently plugging or unplugging the earth. Moreover, the documents FR 2 984 621, FR 2 977 086 and FR 2 964 506 also illustrate certain aspects of these loaders.

The subject of the invention is a battery charger for a non-isolated electric or hybrid motor vehicle comprising, for example, connected in succession, at least one input filter, a rectifier, and a battery, powered by a network of external power supply. Alternatively, the charger uses the electric machine and the vehicle traction inverter, in addition to the rectifier stage connected to the input filter. The charger comprises a calculation means connected at input to a network type sensor, to a current sensor, to a voltage sensor connected between the power supply network and the input filter, the calculation means 3021816 3 comprising means for detecting the presence of a neutral, and means for estimating a leakage current, the calculating means being able to control the connection of passive leakage current compensation means when a neutral 5 is detected by said means for detecting the presence of a neutral, and said calculating means being able to control the opening of contactors arranged upstream of the rectifier and the disconnection of said passive compensation means, as a function of the comparison of the current leakage estimated by said estimating means to a leakage threshold value upon charging of said battery. The passive compensation means may comprise at least one compensation circuit per type of single-phase or three-phase power supply network. The passive compensation means may be included in the input filter. The leakage threshold corresponds to a touch current threshold value of 15 mA at the time of establishing the touch current, then decreasing to approximately 3.5mA 200ms after the establishment of the touch current.

The invention also relates to a method for controlling a battery charger for a non-isolated type of electric or hybrid motor vehicle comprising, connected in succession, at least one input filter, a rectifier and a battery, powered by an external power supply network. The method comprises the following steps: the type of power supply network is identified, if the detected network is of the single-phase type and the presence of a neutral is identified, the setting of passive current compensation is controlled. leak, the load is started, then it is determined whether the leakage current is greater than a leakage threshold value, if the detected network does not include a neutral or is a biphase or three-phase type network, the starting of the charge 3021816 4 then it is determined whether the leakage current is greater than a leakage threshold value corresponding to a touch current threshold value, if a leakage current greater than a leak threshold value is detected, controls opening of the chopper switches, opening of the contactors and opening of the passive compensation switches, if passive compensation is present. The touch current threshold is 15 mA when the touch current is established, then a value less than or equal to about 3.5 mA at about 200 ms after the touch current is established. It can be detected that the network does not include a neutral or is a two-phase or three-phase type network, start the load start without setting up a passive leakage current compensation, and the load is interrupted following the detecting an exceeding of said leakage current threshold by said leakage current. The interruption of the load can be followed by: a step of characterizing said network in which it is determined whether a neutral is available, said characterization step being followed by a step of connection of passive current compensation means leakage and recovery of said load when the availability of a neutral is detected during said characterization step, or a step of recovery of said load without passive compensation of leakage current when a neutral has not not detected as available during said characterization step. The said interrupting step can take place only if the said overflow exceeds a duration of about two hundred milliseconds. The passive compensation means may comprise at least one compensation circuit per type of single-phase, two-phase or three-phase power supply network, the setting up of compensations is controlled by connecting at least one of the passive compensation circuits corresponding to the type of network. power supply detected.

Further objects, features and advantages of the invention will be apparent from the following description, given by way of non-limiting example and with reference to the accompanying drawings in which: FIG. 1 illustrates a loader non-isolated battery powered by a three-phase network according to the state of the prior art, - Figure 2 illustrates a non-isolated battery charger powered by a single-phase network according to the state of the prior art, - Figure 3 illustrates the sources of leakage currents of a non-insulated battery charger according to the state of the art, FIG. 4 illustrates the evolution of the touch current threshold as a function of the duration of the touch current, FIG. illustrates the main elements of a motor vehicle battery charger; FIG. 6 illustrates the main elements of a motor vehicle battery charger comprising a variant of the motor vehicle battery charger; passive compensation circuits; FIG. 7 illustrates the main steps of the charge control method, and FIG. 8 illustrates an example of evolution of the touch current during a load using a charger according to the invention. . It has been found by the inventors that a compensation of the leakage currents was not always necessary, especially when the power supply network has no neutral or when the network 25 is two-phase or two-phase 120 °. In these cases, in fact, differential monitoring of the incoming / outgoing current variations is sufficient. For a 180-degree two-phase network, a single-phase network or a three-phase network, compensation for leakage currents (active or passive) is generally necessary. Such compensation can for example be envisaged for the two-phase 180 ° case when a leakage current threshold is reached. In such a context, the charger and the charge control method allow optimal use with regard to the normative requirements (3.5mA max touch current) of the various possible safety mechanisms. FIG. 5 illustrates a battery charger for a motor vehicle of the non-isolated type comprising in particular a calculating means 7 connected at input to a current sensor 8 and a voltage sensor 9 connected between the power supply network 1 and the filters. input 2. The calculation means comprises means for detecting the presence of a neutral, and means for estimating a leakage current. These means are, for example, means for receiving a presence signal of a neutral or of a leakage current value, transmitted by a presence detection circuit of a neutral, or by a device for leakage current estimation. The calculation means 7 is furthermore connected at the output to contactors 10, to passive compensation means 11 and to the windings of the electrical machine 4. The contactors 10 are arranged between the power supply network 1 and the sensors of FIG. voltage and current 9.8. The passive compensation means 11 are included in the input filter 2.

The network type sensor is located at the input of the input filter 2 (between the supply network 1 and the input filter 2). It consists of voltage sensors between each phase and the chassis of the vehicle. It may also include line current sensors on each phase.

The calculation means 7 allow the passive compensation of the leakage currents making it possible to limit the leakage currents in an appropriate manner together with the measurement of the current sensor and the voltage sensor, possibly combined within a differential monitoring sensor. The differential leakage current monitoring sensor continuously monitors the leakage currents and provides current and voltage measurements to the calculation means 7 so that it can act on the power electronics or on the power electronics. the switches for energizing the charging apparatus in the event of a leakage current exceeding a leakage threshold value, corresponding to a touch current threshold value. The touch current detector 8 has the characteristic of reproducing the bandwidth of the touch current measurement circuits by means of a current sensor and a filter. A leakage current is an abnormal current originating from the leaks of the various electrical, electronic and electrotechnical components. The leakage current is collected by the vehicle mass and directed to the ground in order to be evacuated. In the absence of a ground connection, and if they are not compensated, the leakage currents can locally charge a part of the vehicle and give rise to electrical discharges or shocks. A touch current is a current flowing through the body of an individual touching the vehicle instead of flowing into the earth. Unlike a leakage current, only a portion of the current flows through an individual as a function of frequency, which is taken into account in the touch current detector by the use of a filter. The leakage current and the touch current are measured by a differential sensor measuring the common mode at the power supply. There are several remarkable thresholds of touch current. An intensity of 5mA corresponds to the threshold of not let go, from which the muscles of the individual in contact with the vehicle are kept contracted against his will. A current of 30mA corresponds to a threshold of danger, which can lead to the death of the individual. Conventionally, a current threshold of touching is fixed at the value of 3.5mA RMS so as to provide a design tolerance vis-à-vis the leakage currents while remaining far from the threshold not to let go.

However, the inventors have found that different touch thresholds can be used depending on the time elapsed since the touch current was established. It is thus possible to tolerate transient currents, which are not perceived by the individual and which do not present dangerousness, greater than the threshold of 3.5mA RMS. The load can then continue, as opposed to fixed-threshold loaders. The invention therefore advantageously uses a touch current threshold mimicking the threshold of human perception which renders the safeties of the charger less sensitive to transient currents. This current threshold is advantageously fixed above 3.5 mA RMS in the first 200 milliseconds after the beginning of the flow of the touch current, a user actually feeling a current of 3.5 mA RMS after 200 milliseconds . The tap current threshold 10 follows a decreasing iso function that is approximately 15 mA at Oms and 3.5 mA at approximately 200 ms, and then converges at 3 mA after a few seconds. Such an evolution of the current threshold is illustrated in FIG. 4. The calculation means 7 is thus able to connect or disconnect the passive compensation means 11 as a function of the data received. The passive compensation circuits 11 are known from the state of the prior art, in particular in the documents FR 2 964 506 and FR 2 977 086. FIG. 6 illustrates a variant of the passive compensation circuits disclosed in these documents, for the purposes of FIG. compensation of the leakage capacity of the charger downstream of the input filter. A first winding of a transformer T connected between the phase and the neutral of the power supply circuit 1, 25 and a second winding connected by one end to the neutral of the power supply circuit 1 can be seen. The other end of the second winding is connected to a first arm D1, D2 of a diode bridge, to the cathode of a first diode D1 and to the anode of a second diode D2.

The second arm of the diode bridge D3, D4 comprises a neutral connection of the power supply circuit 1 connected between the cathode of a third diode D3 and the anode of a fourth diode D4.

The anode of the first diode D1 and the anode of the third diode D3 are connected together. The cathode of the second diode D2 and the cathode of the fourth diode D4 are connected together to an armature of a capacitor C, the other armature being connected to ground. Such a passive compensation circuit makes it possible to generate a current in phase opposition with the leakage currents so that the effective leakage current is reduced or canceled. It is thus possible to compensate for and monitor leakage current so as to be within a touch current threshold of 3.5 mA, the limit value of the touch sensitivity for a human being. In addition, several passive or active compensation circuits may be provided and connected to the charger. For each type of network and operating phases of the charger, the appropriate compensation circuit is then connected and used. For example in single-phase without neutral, no compensation will be applied. For a network having a recognizable neutral reference, filter and filter offsets will be positioned to reduce leakage currents. Contactors at appropriate locations are required to enable / disable these filters. One or more filters can be provided for each use case. The charge control method is illustrated in FIG. 7. It can be seen that the method starts with a first step of identifying the type of power supply network. Three characteristics are identified: the quality of the earth connection, (by the method of measuring the earth quality known from the state of the art, in particular in the document FR 2 976 361), the position of the neutral conductor (at means of voltage measurements between the phases 30 and the chassis) and the nature of the power supply, in particular from a single-phase, three-phase, two-phase or two-phase 120 ° network by means of voltage measurements between each of the phases of the supply network and the chassis of the electric vehicle, as well as current measurements on each of the phases.

If the detected network is of single-phase type and the neutral is identified, the process proceeds to a second step 11 in which the control of the compensation consisting of passive components (for example: diodes, resistors, 5 capacitors, transformers, chokes, ...), then the start of the load and then it is determined whether the leakage current is greater than a leak threshold value. If the detected network does not include a neutral or is a two-phase or three-phase type network, the process continues to a third step 12 during which the charge is started and then the leakage current is determined to be higher. at a leak threshold value. During these two steps, if a leakage current higher than a leakage threshold value, for example 5 mA corresponding to a touch current threshold of 3.5 mA, is detected, the process is continued at a fourth step 13a. 13b during which it controls the opening of the passive compensation switches, switching switches and opening of the contactors. The process then resumes in the first step.

Otherwise, charging continues until completion and the process ends in step 14. A repeat of the process in step 10 is shown in FIG. 8: if in step 12 a exceeding the leakage current threshold by more than about 200 ms, the term "about" here meaning to within 10%, the charge is cut according to step 13a. This power cut is followed by a new network characterization step, in which it is determined whether a neutral is now available. In this new step 10 the determination of the type of network or the quality of the earth is optional (as already done in the first step 10). This new step 10 is followed by a new step 11 of connection of passive leakage current compensation means 3021816 11 when the availability of a neutral has been detected in the new step 10. Once the setting up of passive compensation of leakage current, recovery of the load is controlled and the load 5 continues in step 14 during which the level of the leakage current remains below the leakage current threshold. The level of the leakage current is indeed always monitored by the charger according to the invention, and it is assumed in this example of use that the leakage threshold is not re-exceeded. The level of the leakage current is even lowered during this step 14 with respect to the level of the leakage current before the interruption of the charge during step 13a, since before this interruption the neutral is not available, the passive compensation means were not connected. The charge interruption time due to step 13a in this exemplary embodiment is about 5 seconds. On the contrary, when the availability of a neutral has not been detected in the new step 10, it is followed by a new step 12 of recovery of the load without setting up compensation. This method thus makes it possible, for example, for charging from a three-phase network to connect the passive leakage current compensation means only if necessary, during charging. In a variant, these passive compensation means are connected from the beginning of the load when the network is of three-phase type.

Claims (9)

REVENDICATIONS1. Battery charger for an uninsulated type of electric or hybrid motor vehicle comprising, connected in succession, at least one input filter (2), a rectifier (3), and a battery (6) powered by a supply network external device (1), characterized in that it comprises a calculation means (7) connected at input to a network type sensor, to a current sensor (8), to a voltage sensor (9) connected between the power supply network (1) and the input filter (2), the calculation means comprising means for detecting the presence of a neutral, and means for estimating a leakage current, the computing means (7) being able to control the connection of passive compensation means (11) leakage current when a neutral is detected by said means for detecting the presence of a neutral, and said calculating means being suitable controlling the opening of contactors (10) arranged upstream of the rectifier (3) and the disconnection ion of said passive compensation means, as a function of the comparison of the leakage current estimated by said estimating means, to a leakage threshold value, during a charge of said battery. 2. The charger of claim 1, wherein the passive compensation means (11) comprise at least one compensation circuit per type of single-phase or three-phase power supply network. 3. Charger according to any one of the preceding claims, wherein the passive compensation means (11) are included in the input filter (2). 4. A charger according to any one of the preceding claims, wherein the leakage threshold corresponds to a touch current threshold of 15 mA when establishing the touch current, and a touch current threshold of less than or equal to 3.5mA approx 200ms after touch current is established. 3021816 13 5. A method of controlling a battery charger for a non-isolated type of electric or hybrid motor vehicle comprising, connected in succession, at least one input filter (2), a rectifier (3), and a battery (6). , powered by an external power supply network (1), characterized in that it comprises the following steps: the type of power supply network is identified, if the detected network is of single-phase type and the presence of a neutral is identified, it controls the establishment of 10 passive compensation of leakage current, it controls the start of the load and then determines if the leakage current is greater than a leakage threshold value, if the detected network does not include a neutral or is a two-phase or three-phase type network, it controls the start of the load 15 and then it is determined if the leakage current is greater than a leakage threshold value, if a leakage current higher than a V Leak threshold value corresponding to a touch current threshold value, the opening of the switching switches, the opening of the contactors, and the opening of the passive compensation switches are controlled if passive compensation is present. The method of claim 5, wherein the touch current threshold is 15 mA when establishing the touch current, and then less than or equal to about 3.5 mA 200ms after the touch current is established. 7. Method according to any one of claims 5 or 6, wherein it is detected that the network does not include a neutral or is a two-phase or three-phase type network, start the start of the load without setting up a passive compensation of leakage current, and the charging is interrupted following the detection of an exceeding of said leakage current threshold by said leakage current, characterized in that the interruption of the charge is followed: 3021816 14 - d a step of characterizing said network in which it is determined whether a neutral is available, said characterization step being followed by a step of connecting means for passive compensation of leakage current and recovery of said load when the availability of a neutral is detected during said characterization step, or a step of resuming said load without passive compensation of leakage current when a neutral has not been detected as said available during said characterization step. The method of claim 7, wherein said interrupting step occurs only if said exceeding exceeds a duration of about two hundred milliseconds. 9. A method according to claim 7 or 8, wherein the passive compensation means (11) comprising at least one compensating circuit per type of single-phase, two-phase or three-phase power supply network, the establishment of compensation in connecting at least one of the passive compensation circuits corresponding to the type of power supply network detected.