JPH0946913A - Charger for electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the setting of the timing of controlling the switching operation of a switching element constituting, especially, a DC-AC converter. SOLUTION: On the output side of a rectifier circuit 3 is a series circuit consisting of a reactor 70 and a switching element 45 connected in parallel. A DC/AC converter 4 is connected in parallel to the switching element 45. A control circuit 15 controls the switching element 45 and the DC/AC converter 4 so that it may accumulate energy in the reactor 70 by turning on the switching element 45, and that it may supply the DC/AC converter with the output where the output of a rectifier circuit 8 and the output of the reactor 70 are added, by turning off the switching element, when charging a main battery 20 and an auxiliary battery 20 with the AC power source 1 as a power source.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging device for an electric vehicle, and more particularly to a charging device for an electric vehicle in which components of a main battery charger and an auxiliary battery charger are integrated and shared. Is.

[0002]

2. Description of the Related Art As a conventional technique, the Japanese Utility Model Publication No. 63-3333
Japanese Unexamined Patent Publication 7 discloses an electric vehicle charging device in which a charger dedicated to a main battery for driving a vehicle and a charger dedicated to an auxiliary battery for driving an auxiliary system load are integrated. This is small and lightweight by sharing the DC / AC converter and the transformer of each charger and providing a changeover switch on the main battery side for selectively switching between the main battery charger and the auxiliary battery charger. It is intended to reduce the cost.

[0003]

However, the above-mentioned conventional charging device for an electric vehicle requires two changeover switches provided on the main battery side, which have a large capacity according to the current flowing through the main battery. There is a problem that the physique becomes big.

Therefore, the inventors of the present invention have proposed a patent application No. 158 of 1994 as a charging device which does not require the changeover switch.
The charging device described in No. 773 was proposed. In the charging device according to the prior application, in a charging device having a structure in which a DC / AC converter and a transformer for a main battery charger and an auxiliary battery charger are shared, a part of the output voltage of the output winding of the transformer is The first to rectify and output to the main battery
A pair of bidirectional energization elements are used for the output section. In addition to the above-mentioned rectification function, these bidirectional energization elements use high frequency DC power of the main battery when charging the auxiliary battery using the main battery as a power source. It is configured to perform AC conversion and supply to the output winding.

However, in the charging device according to the above-mentioned prior application, a reactor for smoothing the rectified output and supplying the same to the main battery is provided in the first output section, and the auxiliary battery is charged using the main battery as a power source. When
When charging the auxiliary battery with the main battery as the power source, in order to prevent problems such as back electromotive force being generated in this reactor and excessive voltage being applied to the bidirectional energization element,
A switch circuit that short-circuits the reactor is provided.
Therefore, there is a problem that the circuit of the first output section becomes large.

Therefore, the present inventors have proposed a charging device described in Japanese Patent Application No. 118742 of 1995 as a charging device that does not require a reactor and a switch circuit in the first output section. The charging device according to this prior application has a configuration in which a smoothing reactor is connected to the output side of a rectifying circuit that rectifies the electric power from an AC power source.

However, in the charging device according to the above-mentioned prior application, the full bridge-connected four switching elements forming the DC / AC converter are switched at independent timings to cyclically supply energy to the reactor. Since it is configured to accumulate and release the light, there is a problem that it is difficult to set the timing for controlling the switching operation of these switching elements.

In view of the above problems, the present invention provides a charging device having a structure in which a smoothing reactor is connected to the output side of a rectifying circuit for rectifying electric power from an AC power source.
It is an object of the present invention to provide a charging device capable of facilitating the setting of the timing for controlling the switching operation of the switching element forming the / AC converter.

[0009]

According to a first aspect of the present invention, a main battery for driving a vehicle and an auxiliary battery for driving an auxiliary system load are charged using an external AC power source as a power source, and the AC power source is not connected. A charging device for an electric vehicle that charges the auxiliary battery using the main battery as a power source, which is a series circuit including a rectifier circuit that rectifies electric power from the AC power source and a reactor and a switching element, A series circuit connected in parallel to the output side of the circuit and a DC / DC connected in parallel to the switching element.
An AC converter, a transformer that steps up and down the output of the DC / AC converter, and a bidirectional current-carrying element are provided, and a part of the output voltage of the output winding of the transformer is rectified and output to the main battery. When charging the auxiliary battery by using the main battery as a power source, a first output unit that performs high-frequency AC conversion by the bidirectional energization element and outputs the converted output to a part of the output winding; A second output unit that rectifies the output voltage of the unit and outputs the rectified output voltage to the auxiliary battery, and when charging the main battery and the auxiliary battery using the AC power supply as a power source, the switching element is turned on to store energy in the reactor. Is stored, the switching element is turned off, and an output obtained by adding the output of the rectifier circuit and the output of the reactor is added to the DC / To supply to C converter, employing a charging device for an electric vehicle, characterized in that it comprises a control circuit for controlling the switching element and the DC / AC converter.

According to a second aspect of the present invention, the control circuit detects the output waveform and the current waveform of the rectifier circuit, and the current waveform on the output side of the reactor becomes a current waveform corresponding to the voltage waveform of the AC power supply. Switching element and D
The charging device for an electric vehicle according to claim 1, wherein the switching duty ratio of the C / AC converter is controlled.

[0011]

In the charging device for an electric vehicle according to the first aspect of the present invention, when the main battery and the auxiliary battery are charged with the AC power source as the power source, the power from the AC power source is rectified by the rectifier circuit. The output of this rectifier circuit flows to the reactor while the switching element is on,
While energy is stored in the reactor and the switching element is off, the output obtained by adding the output of the reactor to the output of the rectifier circuit is supplied to the DC / AC converter. Apply high-frequency alternating current to the winding. A boosted high-frequency AC voltage corresponding to the high-frequency AC current flowing in the input winding is induced in a part of the output winding of the transformer, and a reduced high-frequency AC voltage is induced in the other part of the output winding. Induced. The AC power generated in a part of the output winding is rectified by the bidirectional energization element in the first output section to charge the main battery. On the other hand, the AC power generated in the other part of the output winding is
It is rectified at the second output portion to charge the auxiliary battery.

On the other hand, when the auxiliary battery is charged with the main battery as the power source, the electric power from the main battery is converted into a high frequency AC by the bidirectional energization element in the first output section and output to a part of the output winding of the transformer. Then, a reduced AC voltage based on the current flowing through a part of the output winding is induced in the other portion of the output winding, and this AC power is rectified in the second output portion to charge the auxiliary battery.

As described above, the charging device for an electric vehicle according to the first aspect uses the bidirectional energization elements, and these bidirectional energization elements have a rectifying function for charging the main battery and a main battery. When the auxiliary battery is charged by using the power source as a power source, the DC power of the main battery is converted into a high frequency AC power and supplied to a part of the output winding. It is not necessary and the device can be downsized.

Further, since the smoothing reactor and the switch circuit are not provided in the first output section, the first output section does not become large.

Further, since the switching element is connected in parallel to the DC / AC converter, the switching operation of the DC / AC converter is controlled at a timing matched with the switching operation of the switching element, whereby periodic energy is accumulated in the reactor. It is now possible to release it. Therefore, the prior application (Patent application No. 1 of 1995)
18742), it becomes easier to set the timing for controlling the switching operation of the DC / AC converter.

According to the electric vehicle charging apparatus of the second aspect, the control circuit detects the output waveform and the current waveform of the rectifier circuit, and the current waveform on the output side of the reactor corresponds to the voltage waveform of the AC power supply. Since it is configured to control the switching element and the switching duty ratio of the DC / AC converter so that the voltage waveform and the current waveform of the AC power supply can be approximately in-phase and similar waveforms, Power factor can be improved.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a block diagram of a charging device for an electric vehicle according to an embodiment.

In FIG. 1, a charging device 100 for an electric vehicle according to the present embodiment is connected to a commercial AC power supply 1 and a main battery 20 for running or driving the electric vehicle.
And the auxiliary battery 21 for driving the auxiliary system load, and the auxiliary battery 21 can be charged by the electric power of the main battery 20 even during traveling.

The charging device 100 comprises a connector 2, a transformer T1, a primary side circuit 130, a secondary side first output section, a secondary side second output section 120, and a control circuit 15. To be done.

The connector 2 is for connecting the charging device 100 to the commercial AC power supply 1.

The transformer T1 has an input winding M1 and an output winding consisting of a part M2 of the output winding and another part M3 of the output winding.

The primary side circuit 130 is provided between the commercial AC power supply 1 and the input winding M1 of the transformer T1. 1
The secondary circuit 130 includes a rectifier circuit 3 for full-wave rectifying the AC power input from the commercial AC power supply 1, a series circuit including a reactor 70 and a switching element 45 connected in parallel to the output side of the rectifier circuit 3, and 4 Switching elements 41
The input side is connected in parallel to the switching element 45 and the output side is the input winding M1 of the transformer T1.
And a DC / AC converter 4 connected to the. Switching element 45 and DC / AC converter 4
Are connected to the control circuit 15 via the control signal line B ′ and the control signal line B, respectively, and are connected to the control circuit 15 as described later.
The switching operation is performed in accordance with the duty ratio control signal from the device, and a high frequency alternating current is passed through the input winding M1 of the transformer T1. The switching elements 41 to 45 can be constituted by semiconductor elements such as mechanical relays, transistors, IGBTs, MOSFETs, and thyristors, but the MOSFETs shown in the figure are preferable, and the DC / AC converter 4 is a full-scale element shown in the figure. A bridge circuit or a push-pull circuit is the most preferable.

The first output section 110 is provided between a part M2 of the output winding of the transformer T1 and the main battery 20.

The first output section 110 is connected to the main battery 20.
Output terminals 111, 1 for connecting the charging device 100 to the
12 is provided.

Further, the first output section 110 full-wave rectifies the high frequency AC current generated by the high frequency AC voltage induced in a part M2 of the output winding of the transformer T1 when the main battery is charged by the commercial AC power supply 1. Main battery 20
The switching circuit 5 has both the function of flowing to the side and the function of converting the electric power of the main battery 20 into a high frequency alternating current and flowing to a part M2 of the output winding when the auxiliary battery is charged by the main battery 20.

The switching circuit 5 is connected to the control circuit 15 by a control signal line C, and has two bidirectional energizing elements which operate according to an instruction signal input from the control circuit 15 via the control signal line C, for example. MOSFET 55, 56
Is configured by push-pull connection. That is, the switching circuit 5 uses the instruction signal from the control circuit 15 to charge the MOSFET when the main battery is charged by the commercial AC power supply 1.
Both 55 and 56 are maintained in an off state, and are configured to perform full-wave rectification by passing a high frequency AC current generated by a high frequency AC voltage induced in a part M2 of the output winding through each parasitic diode of the MOSFETs 55 and 56. ,on the other hand,
When the auxiliary battery is charged by the main battery 20, the MOSFETs 55 and 56 alternately perform a high frequency switching operation according to an instruction signal from the control circuit 15 to convert the electric power of the main battery 20 into a high frequency AC and form a part M2 of the output winding. It is configured to flush.

Further, the first output section 110 includes a smoothing capacitor 7 that smoothes the full-wave rectified voltage by the switching circuit 5 when the main battery is charged by the commercial AC power supply 1.

The first output section 110 is connected to the control circuit 15 by a signal line F for detecting the charging voltage of the main battery 20 and inputting a main battery voltage detection signal to the control circuit 15.

The second output section 120 is provided between the other section M3 of the output winding of the transformer T1 and the auxiliary battery 21.

The second output section 120 has output terminals 121, 12 for connecting the charging device 100 to the auxiliary battery 21.
2 is provided.

The second output section 120 is a high-frequency AC voltage induced in the other section M3 of the output winding of the transformer T1 when the auxiliary battery is charged by the commercial AC power source 1 and when the auxiliary battery is charged by the main battery 20. The rectifier circuit 9 is configured to perform full-wave rectification of the high-frequency alternating current generated by the above, and to flow to the auxiliary battery 21 side. The rectifying circuit 9 includes a pair of rectifying elements 9
1 and 92.

The second output section 120 is connected to the control circuit 15 by a signal line E for detecting the charging voltage of the auxiliary battery 21 and inputting the auxiliary battery voltage detection signal to the control circuit 15. .

The second output section 120 also includes a smoothing reactor 10 and a smoothing capacitor 11 for smoothing the current and voltage that are full-wave rectified by the rectifier circuit 9 when the auxiliary battery is charged.

Next, the charging device 1 configured as described above.
The main operation of 00 will be described.

(1) When the main battery 20 and the auxiliary battery 21 are charged with the commercial AC power source 1 as the power source When the connector 2 is connected to the commercial AC power source 1, the AC power of the commercial AC power source 1 is rectified by the rectifier circuit 3. Full wave rectified.

On the other hand, when the connector 2 is connected to the commercial AC power supply 1, the control circuit 15 is notified via the signal line A that the connector 2 is connected to the commercial AC power supply 1. In response to this, the control circuit 15 detects the charging voltage of the main battery 20 via the signal line F, and controls the switching voltage of the main battery 20 to the set voltage in order to control the charging voltage of the main battery 20.
5 and each switching element 4 of the DC / AC converter 4
The duty ratio (ON / OFF ratio) that determines the switching operation of 1 to 44 is determined, and the duty ratio control signal is output to the switching element 45 and the DC / AC converter 4 via the control signal lines B ′ and B.

Here, in each switching operation of the switching elements 41 to 45, as shown in FIG. 2, only the switching element 45 is turned on in the first ¼ cycle in one cycle and the switching is performed in the next ¼ cycle. Elements 41 and 44
Only the switching element 45 is turned on again in the next quarter cycle, and only the switching elements 42 and 43 are turned on in the last quarter cycle.

FIG. 3 shows such a switching element 41.
~ 45 is a schematic representation of the switching operation for one cycle, ~ in the figure shows the operation sequence for one cycle, and the switching elements not shown in ~ are assumed to be in the off state.

First, as shown in (1), when the switching element 45 is turned on, the input power source, that is, the output of the rectifying circuit 3 is short-circuited via the reactor 70, and energy is accumulated in the reactor 70. Next, as shown in, switching elements 41 and 4
When 4 is turned on, the output of the rectifier circuit 3 and the output of the reactor 70 are added and transmitted to the input winding M1 of the transformer T1, and as a result, the voltage is applied to a part M2 and another portion M3 of the output winding of the transformer T1. Is induced. Next, as shown in, when the switching element 45 is turned on again, the output of the rectifier circuit 3 is short-circuited again via the switching element 45, and energy is stored in the reactor 70. next,
As shown in FIG. 4, when the switching elements 42 and 43 are turned on, the output of the rectifier circuit 3 and the output of the reactor 70 are added and transmitted to the input winding M1 of the transformer T1. As a result, the output winding of the transformer T1 Part M2 and other part M3
A voltage is induced at. In this case, the polarity of the voltage induced in the part M2 and the other part M3 of the output winding in the case of is because the direction of the current flowing in the input winding M1 is opposite to that of the case. It goes without saying that the polarity is opposite to that of the applied voltage.

Since the switching elements 41 to 45 are configured to repeat the switching operation for one cycle as described above, the current and electric energy of the reactor 70 are as shown in FIG. A high frequency AC voltage is generated in each of the part M2 and the other part M3 of the output winding.

The control circuit 15 detects the output waveform of the rectifier circuit 3 through the signal line G and the current waveform of the rectifier circuit 3 through the signal line H by the current sensor 45, and outputs the output of the reactor 70. By controlling the switching duty ratio of the switching element 45 and the DC / AC converter 4 so that the current waveform on the side becomes a current waveform corresponding to the voltage waveform of the commercial AC power supply 1, as shown in FIG. The voltage waveform and the current waveform of No. 1 can be approximately in-phase similar waveforms, and the power factor of the commercial AC power supply 1 can be improved.

The high frequency alternating current generated by the high frequency alternating voltage induced in the part M2 of the output winding is input to the switching circuit 5. In the switching circuit 5, both MOSFETs 55 and 56 are maintained in the off state according to the instruction signal input from the control circuit 15 via the control signal line C.
Therefore, the high-frequency AC current generated by the high-frequency AC voltage induced in the part M2 of the output winding as described above is M
Full-wave rectification is performed by the parasitic diodes of the OSFETs 55 and 56. Further, the full-wave rectified voltage is smoothed by the smoothing capacitor 7, is applied to the main battery 20, and the main battery 20 is charged.

On the other hand, the high-frequency AC current generated by the high-frequency AC voltage induced in the other portion M3 of the output winding is full-wave rectified by the rectifying circuit 9, and the full-wave rectified current and voltage are smoothed by the smoothing reactor 10. And smoothing capacitor 11
And the smoothed voltage is smoothed by the auxiliary battery 2
1 and the auxiliary battery 21 is charged.

(2) When the auxiliary battery 21 is charged with the main battery 20 as the power source When the connector 2 is disconnected from the commercial AC power source 1 and the auxiliary battery 21 is charged with the main battery 20 as the power source, control is performed. The circuit 15 controls the MOS of the switching circuit 5 with a duty ratio based on the charging voltage detected via the signal line E so as to control the charging voltage of the auxiliary battery 21 to the set voltage.
The FETs 55 and 56 are operated by high frequency switching. As a result, a high-frequency AC current flows in a part M2 of the output winding of the transformer T1, and a high-frequency AC voltage is induced in the other part M3 of the output winding. The high-frequency AC current generated by this high-frequency AC voltage is full-wave rectified by the rectifier circuit 9, further smoothed by the smoothing reactor 10 and the smoothing capacitor 11, and supplied to the auxiliary battery 21, and the auxiliary battery 2
1 is charged.

As described above, the charging device for an electric vehicle according to this embodiment uses MOSFETs (bidirectional energization elements) 55 and 56, and these bidirectional energization elements 5 are used.
In addition to the rectifying function for charging the main battery, the auxiliary battery 21 and the auxiliary battery 21,
When charging the battery, the DC power of the main battery 20 is converted to high frequency AC and supplied to a part M2 of the output winding. Can be miniaturized.

Further, since the smoothing reactor and the switch circuit are not provided in the first output section 110, the size of the first output section 110 can be reduced.

Further, since the switching element 45 is connected in parallel to the DC / AC converter 4, the timing of the switching operation of the switching element 45 can be adjusted.
Switching elements 41 and 44 of the DC / AC converter 4
It becomes possible to set the respective timings of the switching operations of the switching elements 42 and 43 to be the same and the timings of the switching operations of the switching elements 42 and 43 to be set to the same. Therefore, the prior application (1995 patent application No. 118742)
No.) makes it easier to set the timing for controlling the switching operation of the DC / AC converter 4.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an electric vehicle charging device according to an embodiment.

FIG. 2 is a timing chart showing operation timings of switching elements 41 to 45, etc.

FIG. 3 is an operation explanatory diagram schematically showing a switching operation of switching elements 41 to 45 for one cycle.

FIG. 4 is an explanatory diagram showing voltage and current waveforms of each part of the primary circuit 130.

[Explanation of symbols]

 1 AC Power Supply 20 Main Battery 21 Auxiliary Battery 100 Charging Device 3 Rectifier Circuit 4 DC / AC Converter 15 Control Circuit 45 Switching Element 70 Reactor T1 Transformer M2 Part of Output Winding Other M3 Output Winding 110 First Output 55, 56 MOSFET (bidirectional conduction element) 120 Second output section

Claims (2)

[Claims] 1. A main battery for driving a vehicle and an auxiliary battery for driving an auxiliary system load are charged using an external AC power source as a power source, and the auxiliary battery is used as a power source when the AC power source is disconnected. A charging device for an electric vehicle, which charges a battery for an electric vehicle, comprising a rectifier circuit for rectifying electric power from the AC power supply, a series circuit including a reactor and a switching element, and being connected in parallel to an output side of the rectifier circuit. A series circuit, a DC / AC converter connected in parallel to the switching element, a transformer for stepping up / down the output of the DC / AC converter, and a bidirectional current-carrying element, and an output of a part of the output winding of the transformer. While rectifying the voltage and outputting it to the main battery, when charging the auxiliary battery using the main battery as a power source, The first output part for performing high-frequency alternating current conversion by a bidirectional energization element and outputting to a part of the output winding, and the output voltage of the other part of the output winding of the transformer are rectified and output to the auxiliary battery. When the main battery and the auxiliary battery are charged with the second output section that does, and the AC power source as a power source, the switching element is turned on to store energy in the reactor,
The DC / A output is obtained by adding the output of the rectifier circuit and the output of the reactor by turning off the switching element.
A charging device for an electric vehicle, comprising: a control circuit that controls the switching element and the DC / AC converter so as to be supplied to a C converter. 2. The control circuit detects an output waveform and a current waveform of the rectifier circuit, and the switching element and the switching element so that the current waveform on the output side of the reactor becomes a current waveform corresponding to the voltage waveform of the AC power supply. The charging device for an electric vehicle according to claim 1, wherein a switching duty ratio of the DC / AC converter is controlled.