JP2014143814A - Non-contact charging device and charging method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-contact charging device capable of easily implementing constant current charging on a power storage element.SOLUTION: At the side of a primary-side coil 13 of a non-contact feeding transformer, there are provided a DC power source 10, an inverter 12 for generating a high frequency AC from a DC and supplying it to the primary-side coil 13 and a primary-side series capacitor Cs1 connected in series between the primary-side coil and the inverter. At the side of a secondary-side coil 14 of the non-contact feeding transformer, there are provided a double current rectifier circuit 15 in which an AC is rectified and supplied to a power storage element 17, and a secondary-side series resonance capacitor Cs2 connected in series between the secondary-side coil and the double current rectifier circuit. When a primary side is driven by a constant voltage, a secondary-side current to be supplied to the power storage element 17 becomes a constant current. A terminal voltage of the power storage element 17 can be known from the inverter input DC. Only by monitoring a primary-side circuit and adjusting a state of the primary side, constant current charging of the power storage element 17 can be controlled.

Description

  The present invention relates to a non-contact charging device that performs constant-current charging in a non-contact manner with respect to a storage element that has a small internal resistance and that can be charged with a large current, such as an electric double layer capacitor and a lithium ion battery, and a charging method thereof.

In industrial electric vehicles such as electric forklifts and unmanned electric vehicles, lead storage batteries have been widely used as a drive source. However, in recent years, electric double layer capacitors and lithium batteries that can be charged for a short time from lead storage batteries have been used. The switch to ion batteries is progressing.
Since the electric double layer capacitor and the lithium ion battery have a small internal resistance, they can be charged with a large current of several hundred A (short-time charging).

Charging of electricity storage devices with low internal resistance is possible by charging with a constant current and stopping charging when the maximum charging voltage is reached, or by charging at a constant voltage after reaching the maximum charging voltage with constant current charging. “Constant current constant voltage charging method” for charging, or as described in Patent Document 1 below, after reaching the maximum charging voltage by constant current charging, the current value is reduced and constant current charging is repeated. The constant current charging method is used.
In addition, there is a method of automatically contact-connecting the contact between the charging power source and the power storage element, but contact charging or contact sparking occurs in charging of several hundreds of A, so charging by non-contact power feeding without contact (non-contacting) Contact charging) is required.

FIG. 9 shows an outline of the non-contact charging device described in Patent Document 2 below. In this apparatus, an AC / DC power source 100 that generates direct current from an alternating current of a commercial power source and a high-frequency alternating current from the direct current that the AC / DC power source 100 outputs are provided on the primary coil (power transmission coil) 102 side of the contactless power supply transformer. An inverter 101 that is generated and supplied to the primary coil 102, and a primary series capacitor Cs connected in series between the primary coil 102 and the inverter 101, and a secondary side of the non-contact power supply transformer On the coil (receiving coil) 103 side, a rectifier circuit 104 that rectifies the alternating current received by the secondary coil 103, and a secondary parallel resonance connected in parallel between the secondary coil 103 and the rectifier circuit 104. A capacitor Cp and a charging circuit 105 that supplies the direct current rectified by the rectifier circuit 104 to the storage element 106 after converting a current value or a voltage value are provided.
The capacitance value of the secondary side parallel resonance capacitor Cp is set so that the secondary side circuit constitutes a parallel resonance circuit, and the capacitance value of the primary side series capacitor Cs has a primary power source power factor of 1. Is set to be

JP 2003-87991 A JP 2012-182887 A

However, in the non-contact charging apparatus illustrated in FIG. 9, the charging circuit 105 is provided after the secondary side rectifier circuit 104 to perform processing such as setting the supply current to the power storage element 108 to a constant current. It is necessary.
When the charging current reaches several hundreds A, the charging circuit 105 must be composed of a large-capacity semiconductor element, which causes problems such as increased conduction loss and switching noise of the semiconductor element.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a non-contact charging device that can easily carry out constant-current charging of a storage element, and to provide a charging method thereof.

The present invention is a non-contact charging device that charges a power storage element by supplying a constant current to the power storage element, and includes a direct current power source that outputs direct current to a primary coil side of the non-contact power supply transformer, and a direct current power source. An inverter that generates a high-frequency alternating current from an input direct current and supplies the high-frequency alternating current to a primary coil; and a primary-side series capacitor connected in series between the primary-side coil and the inverter; A double current rectifier circuit that rectifies the alternating current received by the secondary coil and supplies it to the storage element on the side coil side, and a secondary connected in series between the secondary coil and the double current rectifier circuit And a charge control unit that controls the inverter input DC voltage input from the DC power source to the inverter to be a constant voltage.
In this non-contact charging device, the primary side series capacitor is arranged on the primary side and the secondary side series resonant capacitor is arranged on the secondary side. Therefore, when the primary side is driven at a constant voltage, The secondary current becomes a constant current. The constant current value of the secondary current can be controlled by the inverter input DC voltage. In addition, since the secondary side rectifier circuit is constituted by a double current rectifier circuit, current loss due to the diode can be reduced.

  In the non-contact charging device of the present invention, since the terminal voltage of the storage element can be detected by monitoring the inverter input DC current, the charging control unit uses the inverter input DC current input from the DC power source to the inverter. , And the start and stop of charging of the storage element are controlled based on the magnitude of the inverter input DC current.

  Moreover, the non-contact charging device of the present invention is capable of constant current charging of a lithium secondary battery or an electric double layer capacitor.

The present invention also provides a DC power source that outputs direct current on the primary coil side of the non-contact power supply transformer, an inverter that generates high-frequency alternating current from direct current input from the DC power source and supplies the high-frequency alternating current to the primary coil, A primary side series capacitor connected in series between the side coil and the inverter, and rectifies the alternating current received by the secondary side coil on the secondary side coil side of the non-contact power supply transformer, Charging the storage element using a non-contact charging device comprising: a double current rectifier circuit supplied to the secondary side; and a secondary side series resonant capacitor connected in series between the secondary side coil and the double current rectifier circuit. The charging method is to monitor the inverter input DC current input from the DC power source to the inverter, and the inverter input DC current corresponds to the lower limit of the operating voltage range of the storage device terminal voltage. When it is current I _DCmin above, the charging start step of starting the charging, charging of the power storage element, a constant voltage driving step of maintaining the inverter input DC voltage input from the DC power source to the inverter in the constant voltage, inverter input A charge stop step of monitoring the DC current and stopping the charging when the inverter input DC current reaches the inverter input current _IDCmax corresponding to the upper limit value of the operating voltage range of the terminal voltage of the storage element. Features.
In this charging method, the start and stop of constant current charging of the storage element can be executed by monitoring the primary side circuit and controlling the primary side circuit.

In the charging method of the present invention, after the charging stop step, an input voltage reduction step for reducing the inverter input DC voltage input from the DC power source to the inverter, and a reduction in which the inverter input DC voltage is set in the input voltage reduction step. Reduced constant voltage drive step to charge the storage element while maintaining the voltage, and charge stop to monitor the inverter input DC current and stop charging when the inverter input DC current reaches the inverter input current _IDCmax again Steps may be added.
Thus, the multi-stage constant current charging method can be executed by monitoring the primary side circuit and controlling the primary side circuit.

In the non-contact charging device of the present invention, the output of the secondary current rectifier circuit can be directly supplied to the storage element to perform constant current charging of the storage element, and between the rectifier circuit and the storage element. There is no need to provide a charging circuit. As a result, the number of semiconductor elements can be reduced as compared with the case where a charging circuit is provided, and current loss and switching noise can be suppressed. Further, the fact that the rectifier circuit is constituted by a double current rectifier circuit also contributes to the reduction of the number of semiconductor elements.
In addition, since the constant current charging of the power storage element can be controlled simply by monitoring the primary side circuit and adjusting the state of the primary side circuit, the charging method is simple.

The figure which shows the non-contact charging device which concerns on embodiment of this invention The figure which shows the primary side coil and secondary side coil of the non-contact charging device of FIG. The figure which shows the equivalent circuit of the non-contact charging device of FIG. The figure which shows the relationship between the inverter input DC voltage and charging current of the non-contact charging device of FIG. The figure which shows the charge procedure in the non-contact charging device of FIG. Charge control operation diagram in the charging procedure of FIG. The figure which shows the charge procedure in the multistage constant current charge in the non-contact charging device of FIG. Charge control operation diagram in the charging procedure of FIG. The figure which shows the conventional non-contact charging device

  FIG. 1 shows a contactless charging apparatus according to an embodiment of the present invention. In this apparatus, an AC / DC power supply 10 that generates direct current from an alternating current of a commercial power supply and a smoothing capacitor 11 that smoothes the direct current generated by the AC / DC power supply 10 are provided on the primary coil 13 side of the contactless power supply transformer. An inverter 12 that generates high-frequency alternating current from direct current input from the AC / DC power supply 10 and supplies the high-frequency alternating current to the primary coil 13, and a primary series capacitor Cs1 connected in series between the primary coil 13 and the inverter 12. And a double current rectifier circuit 15 that rectifies the alternating current received by the secondary coil 14 and supplies it to the storage element 17 on the secondary coil 14 side of the non-contact power supply transformer, A smoothing capacitor 16 for smoothing the direct current generated by the current rectifier circuit 15, and a secondary side series resonant capacitor connected in series between the secondary side coil 14 and the double current rectifier circuit 15. And a s2, further includes a charge control unit 20 for controlling the charging of the to storage element 17 monitors the inverter input DC current and the inverter input DC voltage input from the AC / DC power supply 10 to the inverter 12.

  As shown in FIG. 2A, the primary coil 13 and the secondary coil 14 of the non-contact power supply transformer include a “both-side wound coil” in which an electric wire 132 is wound around a magnetic core 131, and FIG. As shown in (b), a “one-side coil” in which a spiral electric wire 134 is arranged on one side of a circular magnetic body 133 is used.

  The double current rectifier circuit 15 corresponds to a full-wave rectifier circuit including four diodes in which two diodes are replaced by reactors 151 and 152, and the AC voltage input from the secondary coil 14 is positive. A half-wave rectifier circuit that outputs power only when it is negative and shuts off the input when it is negative. Conversely, it outputs power only when the AC voltage input from the secondary side coil 14 is negative, and it is input when it is positive. It consists of two sets with a half-wave rectifier circuit that shuts off. Therefore, the two diodes 153 and 154 do not conduct at the same time, and the number of diodes that are energized is always one.

FIG. 3 shows an equivalent circuit of a circuit portion including the primary side series capacitor Cs1, the secondary side series resonance capacitor Cs2, the primary side coil 13, and the secondary side coil 14 of the contactless charging apparatus. Here, r ′ ₀ indicating the iron loss and winding resistances r ′ ₁ and r ₂ are sufficiently smaller than the corresponding reactances x ′ ₀ , x ′ ₁ , and x ₂ and can be ignored.
The value of the primary side series capacitor Cs1 is set by (Equation 1) so as to resonate with the primary side coil 13 of the non-contact power supply transformer.
Here, ω ₀ = 2πf (f: power supply frequency), x ′ ₀ : secondary conversion excitation reactance, x ′ ₁ : secondary conversion primary leakage reactance.

Further, the value of the secondary side series resonance capacitor Cs2 is set by (Equation 2) so as to resonate with the secondary side coil 14 of the non-contact power supply transformer.
Where x ₂ is the secondary leakage reactance.

At this time, the relationship between the voltage and current of the primary side and the secondary side is expressed by (Equation 3) and (Equation 4).
(Equation 3) indicates that if the primary side is driven with a constant voltage, the secondary side becomes a constant current.

Figure 4 shows the relationship between the charging current I _L of the inverter input DC voltage V _DC and the power storage device 17 to enter from the AC / DC power supply 10 of the non-contact charging device to the inverter 12. Therefore, if the primary side is driven with a constant voltage, the electric storage element 17 can be charged with a constant current. Further, the value of the constant current supplied to the power storage element 17 can be changed by changing the value of the constant voltage on the primary side.
Further, since the relationship of (Equation 4) exists, the terminal voltage V _L of the power storage element 17 can be known by monitoring the inverter input DC current I _IN input to the inverter 12.

The charge control unit 20, while monitoring the AC / DC inverter input DC current input from the power supply 10 to the inverter 12 I _DC and the inverter input DC voltage V _DC, controls the constant current charging of the power storage element 17.
FIG. 5 shows a control procedure of the charging control unit 20. The control procedure will be described with reference to the charge control operation diagram of FIG.
The charge control unit 20 monitors the inverter input DC current I _DC, the inverter input DC current I _DC is equal to or corresponding to the inverter input current I _DCmin above the operating voltage range lower limit value V _Lmin of the terminal voltage of the storage element 17 (Yes in Step 1), the inverter input DC voltage is maintained at the constant voltage V _DC to drive the primary side (Step 2). At this time, as shown in FIG. 6, the electric storage element 17 is charged with a constant current I _L.
Charging of the storage element 17 with the constant current I _L is continued until the inverter input DC current I _DC reaches the inverter input current I _DCmax corresponding to the operating voltage range upper limit value V _Lmax of the terminal voltage of the storage element 17, and I _DC If I _DCmax has been reached (Yes in step 3), charging is terminated (step 4).

FIG. 7 shows a control procedure when performing multi-stage constant current charging, and FIG. 8 shows a charging control operation diagram.
Note that the multistage constant current charging is a method in which the influence of the internal resistance of the power storage element is reduced and charging is performed to a state closer to full charge. Since the terminal voltage of the storage element detected during constant current charging includes the voltage increase caused by the internal resistance of the storage element, the current value is reduced so that the voltage increase due to the internal resistance is reduced. repeat.

In FIG. 7, the procedure from Step 1 to Step 3 is the same as that in FIG.
In Step 3, the inverter input DC current I _DC reaches the inverter input current I _DCmax corresponding to the operating voltage range upper limit value V _Lmax of the terminal voltage of the storage element 17, charging control unit 20, the inverter input DC voltage V _DC Is reduced to, for example, V _DC / 2 (step 5), the inverter input DC voltage is maintained at a constant voltage V _DC / 2, and the primary side is driven (step 6). At this time, as shown in FIG. 8, the storage element 17 is charged with a constant current I _L corresponding to the constant voltage V _DC / 2. The terminal voltage V _L of the storage element 17 decreases temporarily due to a decrease in charging current due to a decrease in charging current, but gradually increases as constant current charging continues.
The charge control unit 20, (Yes in step 7) the inverter input DC current I _DC is, the inverter input current I _DCmax reached again and which corresponds to the operating voltage range upper limit value V _Lmax of the terminal voltage of the storage element 17, a multi-stage constant current If the number of times of charging (number of repetitions) n is 1, charging is terminated (step 9).
On the other hand, if n is 2 or more, the process returns to step 5, the inverter input DC voltage V _DC / 2 is further reduced by half, and the procedure of steps 6 and 7 is repeated a predetermined number of times, and then the charging is terminated (step 9).

Thus, in this non-contact charging device, constant current charging of the storage element can be controlled only by monitoring the primary side circuit and adjusting the state of the primary side circuit. Therefore, charge control is simple.
Further, in this non-contact charging device, the output of the secondary side double current rectifier circuit can be directly supplied to the storage element to perform constant current charging of the storage element, and there is no need to provide a separate charging circuit. For this reason, since the charging circuit is unnecessary and the secondary side rectifier circuit is configured by a double current rectifier circuit, this apparatus can greatly reduce the number of semiconductor elements to be used. Current loss and switching noise can be suppressed.

The non-contact charging device of the present invention is suitable for charging a storage element having a low internal resistance, such as a lithium secondary battery or an electric double layer capacitor, but can also be used for constant current charging of other storage elements. is there.
In addition, here, when performing multi-stage constant current charging, the inverter input DC voltage is reduced by half so that the constant current supplied to the storage element at each stage is reduced by half. The number of multistages can be set arbitrarily.

  The non-contact charging device of the present invention can be widely used for constant current charging of power storage elements arranged in various moving bodies including industrial electric vehicles.

DESCRIPTION OF SYMBOLS 10 AC / DC power supply 11 Smoothing capacitor 12 Inverter 13 Primary side coil 14 Secondary side coil 15 Double current rectifier circuit 16 Smoothing capacitor 17 Storage element 20 Charge control part 100 AC / DC power supply 101 Inverter 102 Primary side coil (power transmission coil)
103 Secondary coil (receiving coil)
DESCRIPTION OF SYMBOLS 104 Rectifier circuit 105 Charging circuit 106 Power storage element 131 Magnetic body core 132 Winding electric wire 133 Circular magnetic body 134 Spiral electric wire Cs Primary side series capacitor Cp Secondary side parallel resonance capacitor Cs1 Primary side series capacitor Cs2 Secondary side series resonance capacitor

Claims (5)

A non-contact charging device for charging a storage element by supplying a constant current to the storage element,
On the primary coil side of the contactless power transformer,
DC power supply that outputs DC,
An inverter that generates high-frequency alternating current from direct current input from the direct-current power supply and supplies the high-frequency alternating current to the primary coil;
A primary series capacitor connected in series between the primary coil and the inverter;
On the secondary coil side of the non-contact power supply transformer,
A double current rectifier circuit that rectifies alternating current received by the secondary coil and supplies the alternating current to the power storage element;
A secondary side series resonant capacitor connected in series between the secondary side coil and the double current rectifier circuit;
And a charge control unit that controls the inverter input DC voltage input to the inverter from the DC power source to be a constant voltage.   2. The contactless charging apparatus according to claim 1, wherein the charging control unit monitors an inverter input DC current input to the inverter from the DC power source, and based on the magnitude of the inverter input DC current. A non-contact charging device that controls start and stop of charging of a power storage element.   3. The contactless charging apparatus according to claim 1, wherein the power storage element is a lithium secondary battery or an electric double layer capacitor. 4. A direct current power source that outputs direct current to the primary side coil side of the non-contact power supply transformer; an inverter that generates high-frequency alternating current from direct current input from the direct current power source and supplies the high frequency alternating current; and the primary side coil; A primary side series capacitor connected in series with the inverter, and a storage element that rectifies the alternating current received by the secondary side coil on the secondary side coil side of the non-contact power supply transformer To the storage element using a non-contact charging device comprising: a double current rectifier circuit to be supplied to the secondary side; and a secondary side series resonant capacitor connected in series between the secondary side coil and the double current rectifier circuit. A charging method for charging
When the inverter input DC current input to the inverter from the DC power source is monitored and the inverter input DC current is equal to or higher than the inverter input current _IDCmin corresponding to the operating voltage range lower limit value of the terminal voltage of the storage element A charging start step for starting charging;
A constant voltage driving step of maintaining an inverter input DC voltage input to the inverter from the DC power supply at a constant voltage during charging of the storage element;
A charge stop step of monitoring the inverter input DC current and stopping charging when the inverter input DC current reaches an inverter input current I _DCmax corresponding to an upper limit value of an operating voltage range of the terminal voltage of the storage element; ,
A charging method comprising: 5. The charging method according to claim 4, further comprising: after the charging stop step,
An input voltage reduction step of reducing an inverter input DC voltage input to the inverter from the DC power supply;
A reduced constant voltage driving step for charging the storage element while maintaining the inverter input DC voltage at the reduced voltage set in the input voltage reduction step;
A charge stop step of monitoring the inverter input DC current and stopping charging when the inverter input DC current reaches the inverter input current I _DCmax again;
A charging method comprising: