JP3604582B2 - Vehicle-mounted bidirectional battery charger using buck-boost chopper - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vehicle-mounted bidirectional battery charger using a step-up / step-down chopper applied to a battery-type electric vehicle used in a new city transportation system or the like.
[0002]
[Prior art]
Conventionally, when a new vehicle is required for an electric vehicle mounted on a battery as a driving source and travels along a track, for example, an electric vehicle or an inspection / measurement vehicle, the length of the track or a change in work content is required. Due to such factors, there are almost no cases where products are delivered with the same specifications as already delivered vehicles, and the specifications of batteries to be mounted are often different. For this reason, the battery charger (ground-mounted type, quasi-constant voltage system) also requires different specifications from those already delivered. Further, in order to bidirectionally step-up or step-down charge between a plurality of batteries having different voltages, two sets of chopper circuits are separately required, and the configuration becomes complicated.
[0003]
[Problems to be solved by the invention]
As described above, in the related art, although the receiving capacity (KVA value) does not particularly change, the common use of the battery charger becomes impossible due to the difference in the battery output voltage. When the number of vehicles is increased, the number of battery chargers has to be increased, the equipment cost is increased, and the operation of the charging equipment is complicated. Furthermore, when rescuing a malfunctioning vehicle (assumed to be another vehicle) that has become unable to run due to some abnormality or overdischarge of the battery by a normal vehicle (assumed to be the own vehicle), a large load is not applied to the battery of the own vehicle. It has been desired to realize a vehicle-mounted battery charging device that can perform towing traveling of another vehicle or supply power to a battery of the other vehicle with a simple configuration.
[0004]
The present invention is intended to solve the above-described problems, and can avoid unnecessary addition of a battery charger, thereby reducing equipment costs. When rescuing a car by its own vehicle (towing the vehicle or supplying power to the battery of another vehicle), it is possible to recover the energy of the battery of the failed car, and it is sufficient to mount the battery as small as possible. It is an object of the present invention to provide a vehicle-mounted bidirectional battery charger using a buck-boost chopper that can be reduced in weight and can be used for multiple purposes.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 uses a step-up / step-down chopper between a battery mounted on the own vehicle and a battery mounted on another vehicle or a charger (hereinafter, referred to as another vehicle). An on-vehicle bidirectional battery charger capable of charging one of the other from the other, connected in series between output terminals of a battery mounted on the own vehicle via a first contactor that is opened and closed. A switching element for step-down operation and step-up operation, and a diode that is connected in parallel to each of the switching elements and allows a current in a direction opposite to a current flowing when the element is turned on to flow when the element is turned off. One end is connected to the midpoint of the switching element, and the other end is connected to a battery of another vehicle via a second contactor that opens and closes in the same manner as the first contactor. And a choke coil which is, wherein when the battery voltage of the vehicle is higher than the battery-voltage other vehicle, and on the first and second contactors, thereby the switching element ON / OFF for the step-down operation Then, the battery of the own vehicle is stepped down from the battery of the own vehicle, and the switching element for boosting operation is turned on / off, so that the battery of the own vehicle is boosted and charged from the battery of the other vehicle. The switching element for the step-down operation and the step-up operation connected to is further connectable between the output terminals of the battery of another vehicle via a third contactor different from the first and second contactors, and The other end of the choke coil, one end of which is connected to the midpoint of the switching element connected in series, is connected via a fourth contactor which performs the same opening and closing operation as the third contactor. When the battery voltage of the other vehicle is higher than the battery voltage of the own vehicle, the third and fourth contactors are turned on, and the switching element for step-down operation is turned on / off. By turning off the battery of the own vehicle, the battery of the own vehicle is stepped down from the battery of the other vehicle, and by turning on / off the switching element for boosting operation, the battery of the own vehicle is boosted and charged from the battery of the own vehicle. It was done.
[0006]
In the above configuration, the battery voltage of the own vehicle is changed to the battery voltage of the other vehicle by using a pair of boosting and stepping-down choppers including switching elements for step-down operation and step-up operation and choke coils extracted from the middle point of the switching elements. When it is higher than this, by turning on the first and second contactors and operating the switching element for the step-down operation, the battery of the own vehicle can be step-down charged from the battery of the own vehicle by the chopper action. As a result, power can be supplied to a faulty vehicle having an overdischarged battery. By operating the switching element for boosting operation, the battery of the own vehicle can be boosted and charged from the battery of another vehicle. Thereby, when towing the failed vehicle, the energy of the battery of the failed vehicle can be recovered. It should be noted that the own vehicle and the other vehicle are in a relative relationship, and include ones that are interchanged with each other.
[0008]
Further, when the battery voltage of the other vehicle is higher than the battery voltage of the own vehicle, the third and fourth contactors are turned on and the switching element for step-down operation is operated, so that the battery of the own vehicle is changed from the battery of the own vehicle. Can be step-down charged. By operating the switching element for boosting operation, the battery of another vehicle can be boosted and charged from the battery of the own vehicle. Thus, depending on whether the voltage of the battery of the own vehicle or the other vehicle is higher, a predetermined set of contactors is turned on, and either the switching element for the step-down operation or the switching element for the step-up operation is operated, thereby achieving a desired operation. A charging operation can be performed.
The operation of the contactor may be automatically performed based on the battery voltage detection result. In many cases, the operator determines which battery is to be charged in a step-down or step-up manner (providing an ON / OFF signal to the switching element) because the operator knows the abnormal situation of the own vehicle and the other vehicle. What should I do?
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a vehicle-mounted bidirectional battery charger according to an embodiment of the present invention will be described with reference to FIG. The present charging apparatus uses a step-up / step-down chopper between a battery BAT1 mounted on the own vehicle 1 and a battery BAT2 mounted on another vehicle 2 or a charger (other vehicle in the claims). Can be charged in both directions. Switching elements Q1 and Q2 for the step-down operation and the step-up operation are connected in series between the output terminals of the battery BAT1 of the own vehicle 1 via the first contactor M1-1 which is opened and closed. Diodes D1 and D2 are connected in parallel to the switching elements Q1 and Q2, respectively, to pass a current in a direction opposite to a current flowing when the element is turned on when the element is turned off. Further, one end of a choke coil L shared by the step-up and step-down operations is connected to a middle point of the switching elements Q1 and Q2, and the other end thereof performs the same opening and closing operation as the first contactor M1-1. Is connected to the battery BAT2 of the other vehicle 2 via the.
[0010]
In the above configuration, when the voltage (Vb1) of the battery BAT1 of the own vehicle 1 is higher than the voltage (Vb2) of the battery BAT2 of the other vehicle 2, the first and second contactors M1-1 and M1-2 are turned on to reduce the voltage. By turning on / off the switching element Q1 for operation, the battery BAT1 of the own vehicle 1 is stepped down and charged from the battery BAT1 of the other vehicle 2 by the chopper action (current at that time is indicated by a solid line and a broken line). This charging operation is used when power is supplied in a case where the other vehicle 2 is a faulty vehicle with excessive battery discharge.
[0011]
Further, by turning on / off the switching element Q2 for boosting operation, the battery BAT1 of the other vehicle 2 is boosted and charged from the battery BAT2 of the other vehicle 2 by the chopper action (the current at that time is indicated by a dashed line). Indicated by a two-dot chain line). This charging operation is used to recover the energy of the battery BAT2 of the other vehicle 2 when the other vehicle 2 is a malfunctioning vehicle that cannot run and is towed by the own vehicle 1. Thus, bidirectional charging can be performed with a simple configuration using only one set of step-up and step-down choppers. Note that the own vehicle 1 and the other vehicle 2 are in a relative relationship, and may be replaced with each other.
[0012]
Further, the switching elements Q1 and Q2 in series are connected between the output terminals of the battery BAT2 of the other vehicle 2 via a third contactor M2-1 different from the first and second contactors M1-1 and M1-2. And the other end of the choke coil L can be connected to the battery BAT1 of the own vehicle 1 via the fourth contactor M2-2 that performs the same opening and closing operation as the third contactor M2-1.
[0013]
In this configuration, when the voltage (Vb2) of the battery BAT2 of the other vehicle 2 is higher than the voltage (Vb1) of the battery BAT1 of the own vehicle 1, the third and fourth contactors M2-1 and M2-2 are turned on to reduce the voltage. By turning on / off the switching element Q1 for operation, the battery BAT1 of the own vehicle 1 is step-down charged from the battery BAT2 of the other vehicle 2. In addition, the battery BAT1 of the own vehicle 1 is boosted and charged from the battery BAT1 of the own vehicle 1 by turning on / off the switching element Q2 for the boosting operation.
[0014]
As described above, a predetermined set of contactors is turned on depending on whether the voltage of the battery of the own vehicle 1 or the other vehicle 2 is higher, and one of the switching elements Q1 and Q2 for step-down operation or step-up operation is turned on. By operating the above, a desired charging operation can be obtained. The operation of the set of contactors M1-1 and M1-2 and the set of contactors M2-1 and M2-2 may be automatically performed based on the battery voltage detection result as described later. Also, which of the batteries is charged in a step-down or step-up manner (an on / off signal is applied to the gate terminals of the switching elements Q1 and Q2) is automatically determined according to the detection result of the abnormal situation of the own vehicle 1 and the other vehicle 2. It can be appropriately performed appropriately.
[0015]
Further, the present apparatus is provided with an arithmetic unit 5 for controlling the above operation, and the arithmetic unit 5 receives the respective battery voltages (VF1, VF2) and the current (CF) detected by the current sensor CS. When voltage VF1 (VF2) of battery BAT1 is high, contactors M1-1 and M1-2 (M2-1 and M2-2) are turned on. If the charging plug of the own vehicle 1 is connected to the charging plug of the other vehicle 2 (or the stationary charger), the arithmetic unit 5 detects the voltage difference and contacts the contactors M1-1, M1-2, or M2. -1 and M2-2 are turned on, and when an operation instruction for charging the battery of the own vehicle 1 (other vehicle 2) is input, the constant voltage and the constant current are maintained until VF1 (VF2) reaches the set voltage. Charge the battery.
[0016]
The present invention is not limited to the configuration of the above embodiment, and various modifications are possible. For example, which battery is charged by stepping down or stepping up (application of an on / off signal to the gate terminals of the switching elements Q1 and Q2) In many cases, the operator may give an instruction because the operator knows the abnormal situation of the own vehicle 1 and the other vehicle 2 in many cases.
[0017]
【The invention's effect】
As described above, according to the vehicle-mounted bidirectional battery charger using the buck-boost chopper according to the first aspect of the present invention,
(1) With a simple configuration using only one set of chopper circuits composed of switching elements for step-down operation and step-up operation and a common choke coil, bidirectional switching between the battery of the own vehicle and the battery of another vehicle is possible. Can be charged.
(2) It is possible to receive charging from a charger for an electric vehicle (delivered vehicle) that has already been delivered (the charger can be diverted). Therefore, even if the battery voltage installed in each vehicle is different, new charging can be performed. There is no need to add more equipment, and equipment costs can be reduced.
(3) When rescue or towing the other vehicle (other vehicle) of the malfunctioning vehicle to the garage, the energy of the battery of the other vehicle can be collected in the battery of the own vehicle, and therefore, mounted on the own vehicle. The battery may have a minimum capacity, and can be reduced in weight and size.
(4) Power can also be supplied to a vehicle that has become unable to travel due to battery overdischarge.
(5) The charging operation in boosting has a high power factor and is efficient.
[0018]
Furthermore, by switching the contactor according to whether the voltage of the battery of the own vehicle or the other vehicle is higher, and operating either the switching element for the step-down operation or the switching element for the step-up operation, the necessary charging operation is appropriately performed. It can be carried out.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an on-vehicle bidirectional battery charger using a buck-boost chopper according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Own vehicle 2 Other vehicle BAT1, BAT2 Battery M1-1 First contactor M1-2 Second contactor M2-1 Third contactor M2-2 Fourth contactor Q1 Switching element Q2 for step-down operation Switching element D1 for step-up operation D2 Diode L Choke coil

Claims (1)

In-vehicle type capable of charging one of the other between a battery mounted on the own vehicle and a battery mounted on another vehicle or a charger (hereinafter, referred to as another vehicle) using a buck-boost chopper. A bidirectional battery charger,
A switching element for step-down operation and step-up operation connected in series via a first contactor that is opened and closed between output terminals of a battery mounted on the own vehicle;
A diode that is connected in parallel to each of the switching elements and that allows a current flowing in a direction opposite to a current flowing when the element is turned on to flow when the element is turned off;
A choke coil having one end connected to the middle point of the switching element and the other end connected to a battery of another vehicle via a second contactor that performs the same opening and closing operation as the first contactor, and which is used for step-up and step-down operations; With
Wherein when the battery voltage of the vehicle is higher than the battery-voltage other vehicle, said first and second contactor is turned on, by turning on / off the switching element for the buck operation, other from the vehicle battery By stepping down the battery of the car and turning on / off the switching element for the step-up operation, the battery of the own car is stepped up and charged from the battery of the other car,
The switching elements for the step-down operation and the step-up operation connected in series are further connectable between the output terminals of a battery of another vehicle via a third contactor different from the first and second contactors, And,
The other end of the choke coil, one end of which is connected to the midpoint of the switching element connected in series, can be connected to the battery of the own vehicle via a fourth contactor that performs the same opening and closing operation as the third contactor. ,
When the battery voltage of the other vehicle is higher than the battery voltage of the own vehicle, the third and fourth contactors are turned on and the switching element for step-down operation is turned on / off. The step-up / step-down chopper is characterized in that the step-up / step-down chopper and the switching element for the step-up operation are turned on / off to charge the step-up / step-down chopper to the step-up / step-down chopper. Bidirectional battery charger.

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