JP3992652B2 - 3-phase input charger - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention performs full-wave rectification on input three-phase power, supplies the full-wave rectified output to a storage battery via a switching DC-DC converter (converter), and charges an on / off control pulse for a switching element of the DC-DC converter. It is related with the charging device which controls the said charging current by carrying out the pulse width modulation.
[0002]
[Prior art]
FIG. 6 shows a conventional charging apparatus of this type. The three-phase AC power from the three-phase AC power supply 11 is full-wave rectified by a full-wave rectifier circuit 13 in the charging device 12, and the full-wave rectified output is supplied to the storage battery 15 via the switching DC-DC converter 14. Charged. In the DC-DC converter 14, for example, full-wave rectified power is converted into high-frequency AC power, such as 20 kHz, by an inverter 16 formed of a high-voltage semiconductor switching element such as IGBT, and this AC power is converted as necessary. Then, the voltage is boosted by the insulating transformer 17, and the output of the transformer 17 is rectified and smoothed by the rectifier circuit 18 to become DC power, and this DC power is supplied to the storage battery 15.
[0003]
The charging current supplied to the storage battery 15 is detected by the current detection unit 19, and the difference between the detected current value and the set value from the setting unit 22 in the control unit 21 is taken by the error calculation unit 23. In response, the correction unit 24 corrects the reference value from the register 25, and the corrected reference value is supplied to the PWM generation unit 26. The PWM generation unit 26 receives the input modulation signal (corrected reference value). ) Is output, and the switching element of the inverter 16 is controlled to be turned on / off by the pulse width modulation signal. The charging current is held at a set value by feedback control based on this charging current detection.
[0004]
In this charging apparatus, when one phase of the input three-phase power is cut off and a phase defect occurs, the output level of the full-wave rectifier circuit 13 is reduced to 1/3, and the detected current of the current detector 19 is also 1 /. 3 In the normal state, as shown in FIG. 7, the output waveform of the full-wave rectifier circuit 13 has curves 27 _UV , 27 _VW , 27 _WU corresponding to the three interphase voltages before the disconnection. For example, the power line 10U is disconnected. Then, the interphase voltage between the power lines 10U and 10V and the interphase voltage between the power lines 10W and 10U become 0, and the output of the full-wave rectifier circuit 13 becomes a rectified output of only the interphase voltage between the power lines 10V and 10W. There are no 27 _UV and 27 _WU, only the curve 27 _{VW as} shown in FIG. 2A.
[0005]
In this state, when the inverter 16 is controlled so as to compensate for the decrease in the detection current, in the interval of ΔT close to the peak of the waveform 27 _VW that is not affected by the phase defect, a place where it should operate normally is considerably allowed. Control is performed so that a large current flows, and there is a possibility that elements constituting the inverter 16, particularly switching elements, may be destroyed. In order to avoid such a state, as shown in FIG. 6, the primary sides of the transformers T _UV , T _VW , T _WU are respectively connected between the two phases of the three-phase power lines 10U, 10V, 10W of the full-wave rectifier circuit 13. The interphase voltage detectors D _UV , D _VW , D _WU are connected to the secondary sides of the transformers T _UV , T _VW , T _WU , respectively, and the power lines 10U, 10V, 10W are connected by any of these inter-phase voltage detectors. When any one of the interphase voltages between the two wires is equal to or lower than a predetermined value, the charging operation of the charging device is stopped.
[0006]
[Problems to be solved by the invention]
Thus, conventionally, three transformers T _UV , T _VW , T _WU and their phase voltage detectors D _UV , D _VW , D _WU have been used to detect phase defects. Each of the transformers is relatively large because of a high voltage, and there is a problem that the overall structure is relatively large.
[0007]
[Means for Solving the Problems]
According to one aspect of the present invention, the zero-cross point of one phase voltage in the input three-phase power is detected by the zero-cross detector, and is synchronized with this zero-cross point every one-third period between adjacent points of the zero-cross point. Then, the effective value or average value of the charging current or voltage is calculated as an output value by the output value calculation unit, the error between the output value and the set value is calculated as an error signal by the error calculation unit, and the error signal is zero. The width of the switching signal with respect to the switching element of the switching type DC-DC converter is controlled by the correction unit by the error signal so that the error signal before the error signal for each one-third period between the zero cross points. Is detected by the fluctuation detection unit, and when the detected fluctuation amount exceeds the threshold value, the charging operation is controlled to be stopped by the charging stop unit.
[0008]
According to another aspect of the present invention, the full-wave rectified output is converted into a voltage by the voltage conversion unit, and the zero-cross point of one phase voltage in the input three-phase power is detected by the zero-cross detection unit and synchronized with the detected zero-cross point. Then, the output of the voltage conversion unit is sampled by the sampling unit every one third between the adjacent zero cross points, and when the sampling value becomes equal to or less than the threshold value, the charging operation is stopped by the charging stop unit.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Prior to the description of the embodiment of the present invention, a charging device that applies the present invention and controls the switching elements of a preferred switching type DC-DC converter will be described with reference to FIG. In FIG. 8, the same reference numerals are assigned to the parts corresponding to those of the apparatus shown in FIG.
In this charging apparatus, the control unit 21 is provided with a reverse phase generation unit 31. The negative phase generation unit 31 generates a negative phase corresponding value corresponding to the negative phase of the full wave rectification output waveform of the full wave rectification circuit 13. That is, for example, as shown in FIG. 7, a curve corresponding to the curve 32 in which the ripple component of the full-wave rectified output waveform 28 is reversed (inverted) is obtained. Although the curve 32 is shown as being continuous, it is actually obtained as a digital value sampled at intervals of the switching period with respect to the switching element of the inverter 16.
[0010]
The period T _{V of the} curve 32 is 1/6 of the one-phase period T _A of the input three-phase AC power. Each reverse-phase corresponding value in the period T _V, i.e. pulse width modulation unit sample value as a modulation signal when generating the pulse width modulated signal with (PWM generator) 26, the average current (effective value) is, the conventional In the charging device, each negative phase corresponding value (sample value) within the period T _V is set in advance so that it is equal to the average current (effective value) in the same section (T _V ) when the reference value is a pulse width modulation signal. Decide it.
[0011]
The correction unit 33 corrects the effective value of the output current of the inverter 16 to the target value (set value) with respect to the negative phase corresponding value from the negative phase generation unit 31, and the corrected reverse The phase-corresponding value is supplied as a control value (modulation signal) to the PWM generation unit (pulse width modulation unit) 26 to generate a pulse width modulation signal, and the switching element of the inverter 16 is on / off controlled by this pulse width modulation signal. .
In this configuration, the value corresponding to the negative phase corresponds to the sample value of the curve 32 as shown in FIG. 9A, for example, and this value becomes the minimum value at the peak value portion of the ripple of the three-phase full-wave rectified output 28. The pulse width of the width modulation signal is the minimum width Wmin, the sample value is maximum at the minimum value portion of the ripple, and the pulse width of the pulse width modulation signal is also the maximum value Wmax. The areas of the respective pulse width modulation signals are made substantially the same, that is, as described above, different from the conventional one (FIG. 9B) in which the pulse width W of the pulse width modulation signal is made the same according to each part of the ripple. . In the case of the same correction value, the pulse width modulation value within the same period (cycle) is set to the same effective value as the conventional one. If the width of each pulse of each pulse width modulation signal in one cycle T _V in the case of no correction Oke obtained in advance as described above, the correction value for the charging current control can be used with the same value, each reverse What is necessary is just to change a phase corresponding value according to a correction value in the state which hold | maintained the relative ratio. The negative phase corresponding value generated by the negative phase generation unit 31 is synchronized with the input three-phase power so that the change in the pulse width of the switching in the inverter 16 is as shown in FIG. 9A. For this reason, for example, the zero cross detector 36 is connected between two power lines, for example, 10 U and 10 V via the step-down transformer 34. As shown in FIG. 7, the zero-cross detector 36 detects a time point P _{Z at} which the interphase voltage waveform 27 _UV between the power lines 10U and 10V falls below the zero voltage level, and outputs a synchronization pulse at each zero-cross time point P _Z. It is supplied to the reverse phase generation unit 31. The negative phase generation unit 31 outputs a sample value sequence (negative phase corresponding value sequence) of the negative phase waveform 32 having a cycle of T _V = T _A / 6 in synchronization with the input zero cross point pulse.
[0012]
Embodiment 1
In the first embodiment of the present invention, the switching element of the DC-DC converter is subjected to switching control with a pulse width modulation signal having a minimum width at the peak of the ripple waveform of the three-phase full-wave rectified output and a maximum width at the valley. In addition to the configuration, the present invention is applied to the configuration in which the charging current is controlled to be a predetermined value for each phase of the three-phase power. FIG. 1 shows the functional configuration of the first embodiment with the same reference numerals assigned to the portions corresponding to FIG.
1 cycle T _V min of the waveform of the reverse-phase waveform 32 shown in FIG. 7 is stored in the waveform memory 35. In the three-phase full-wave rectified output waveform 28 for an ideal three-phase AC power, if the amplitude of the three-phase AC power is determined and the switching period of the switching DC-DC converter 14 is determined, one period T _{V of the} ripple Each sample value in can be calculated, and the reciprocal of each sample value can be calculated. Each value of the inverse, i.e. one period T _V content is stored in the waveform memory 35.
[0013]
Meanwhile, one of the phase voltages of the three-phase AC power input to the charging device 12 is inputted to the zero-cross detector 36, a zero-cross point P _Z of the phase voltage is detected. Each time the zero cross point is detected, the n-ary counter 37 is reset. n-ary counter 37, a clock synchronized with the pulse width modulated signal from the PWM generating unit 26, i.e. by counting a clock synchronized with the switching to the switching elements of the inverter 16, when the period of the clock and T _C, n = T When counting the _V / T _C-number of clock is reset, in which repeating counting from zero again.
[0014]
The waveform stored in the waveform memory 35 is sequentially read out in synchronization with the ripple of the full-wave rectified output waveform 28 based on the count value of the n-ary counter 37, that is, the opposite-phase corresponding values are sequentially obtained. The pulse is supplied to the generation unit 26 and a pulse width modulation signal is generated.
The output signal of the inverter 16 is supplied to the output value calculation unit 41. The output value calculation unit 41 is controlled by the zero reset output of the n-ary counter 37, and the effective value or average value of the inverter output signal in one cycle T _V of the ripple. The difference between the effective value or average value and the set target value from the setting unit 42 is obtained by the error calculation unit 43, and the error output is supplied to the correction unit 33. In the correction unit 33, Correction to the anti-phase corresponding value output from the waveform memory 35 is performed so that the output of the error calculation unit 43 becomes zero, that is, the calculated effective value or average value approaches the set target value. That is, for each phase of the three-phase power, control is performed so that the average value or effective value of one cycle T _V of the PWM pulse becomes the target value, and the charging current / voltage is held at a predetermined value. The output value of the output value calculation unit 41 corresponds to the effective value or average value of the charging current / voltage for the storage battery 15.
[0015]
In the first embodiment, a change in the adjacent phase-corresponding correction control amount is detected, and when the change exceeds a predetermined value, it is determined that an open phase has occurred. In FIG. 1, the output error signal of the error calculation unit 43, that is, the correction control signal is temporarily stored in the previous control amount holding unit 61 by the zero reset output of the n-ary counter 37, and the fluctuation detection unit 62 performs the error calculation unit 43. output error signal and a period T _V before the error signal from the previous control amount holding section 61, i.e. the difference between one phase before the error signal, i.e. the detected fluctuation amount of the control amount, the variation amount comparison section 63 The threshold value is compared with the threshold value of the threshold value unit 64. If the threshold value is exceeded, the charging stop unit 65 is controlled by the output of the comparison unit 63, and the charging operation is stopped.
[0016]
As shown in FIG. 2A, the full-wave rectified output waveform becomes a curve 28 in a state where the open-phase has not occurred, to output the effective value E _N of the output value calculation section 41 of each the ripple period T _V, slight value Fluctuated by ΔE _N. Accordingly, as shown in line 66 of the output error signal also Figure 2B than the error calculating unit 43 in this case, variation in every period T _V is small, the amount of variation to be detected from the fluctuation detecting unit 62 at a small value Yes, this is smaller than the threshold value, and the charging stop unit 65 is not controlled.
[0017]
However, when a phase failure occurs and, for example, power from the power line 10U is cut off, the full-wave rectified output waveform becomes the curve 27 _{VW in} FIG. 2A. That is, it becomes a single-phase full-wave rectified output waveform. Therefore, the output rms value of the output value calculation section 41 and the E _A1 in one period T _V of the peak portion of the waveform 27 _VW, becomes substantially the same value as the value E _N when there is no phase failure, the peak portion 1 In one cycle T _V on both sides of the cycle T _V , the value E _A2 is smaller than half of E _A1 . Accordingly, the output error signal from the error calculation unit 43 in this case also has a small value CV ₁ corresponding to E _A1 as in the normal state as shown by the line 67 in FIG. 2B, but in the portion corresponding to E _A2 It is a much larger value CV _{2 than} CV ₁ . The absolute value of the difference between CV ₁ and CV ₂ is output from the fluctuation detection unit 62, which exceeds the threshold value, and the charging stop unit 65 is controlled by the output of the comparison unit 63 to stop the charging operation. Become.
[0018]
Embodiment 2
FIG. 3 shows Embodiment 2 of the present invention with the same reference numerals assigned to the portions corresponding to FIG.
In the second embodiment, the full-wave rectified output from the three-phase full-wave rectifier circuit 13 is branched and supplied to the voltage converter 51, and the full-wave rectified output is converted into a voltage. In this case, it is preferable to insulate the input side and the output side of the voltage converter 51 using an isolation amplifier or the like. The output voltage waveform of the voltage converter 51 is sampled by the A / D converter 52 by the clock from the PWM generator 26 and converted into a digital value, and the reciprocal of each digital value is detected by the reciprocal calculator 53. The calculated reciprocal is supplied to the PWM generation unit 26 through the correction unit 33 as an anti-phase corresponding value.
[0019]
The pulse width modulation signal from the PWM generator 26 is supplied to the DC-DC converter 14 and is also supplied to the output value calculator 41 in a branched manner. The zero-cross point _PZ detection pulse from the zero-cross detection unit 36 is input to the control pulse generation unit 71 to generate a pulse having a period T _V synchronized with the zero-cross pulse, and the output value calculation unit 41 causes the control pulse of the period T _V to generate a pulse. output value calculating unit 41 is controlled to calculate the effective value or the output value of each time period T _V based on the detection zero cross point, which the, obtains the difference between the set value, the correction of the charging current for each period T _V I do.
[0020]
The output value of the output value calculation unit 41 also corresponds to the effective value or average value of the charging current / voltage for the storage battery 15.
From the control pulse generator 71, the output voltage of the voltage converter 51 is sampled by the sampling unit 72 using this control pulse, and the sampled value and the threshold value from the threshold unit 64 are compared by the comparator 63. As in a normal state can be understood from FIG. 2A, the output sampling value of the sampling unit 72 is substantially L _N, for example, power from the power line 10U is if intercepted, in the sampling of each period T _V, consecutive 3 Two of the sampled values are almost L _N , but one is zero. Therefore, when the output sampling value of the sampling unit 72 becomes 0 in the comparison unit 63, that is, when the sampling value is equal to or less than the threshold value, the charging stop unit 65 is controlled by the output of the comparison unit 63, and the charging operation is stopped. Is done.
3, the previous control amount holding unit 61 and the variation detecting unit 62 are provided on the output side of the error calculating unit 43 as shown in FIG. 1, and the output of the variation detecting unit 62 is supplied to the comparing unit 63. Good. It is natural that the threshold value of the threshold value unit 64 is set to a different value when compared with the variation amount of the control amount and when compared with the sampling value.
[0021]
Embodiment 3
The present invention is not limited to the case of using the anti-phase corresponding value, and switching is performed with the same width as shown in FIG. 9B regardless of the ripple phase of the three-phase full-wave rectified output waveform as in the conventional device shown in FIG. The present invention can also be applied to switching control of elements. The embodiment in this case is shown in FIG. 4 with the same reference numerals assigned to the portions corresponding to those in FIGS. In this example, as shown in FIG. 3, the output of the full-wave rectifier circuit 13 is converted into a voltage by the voltage converter 51, and the control pulse generated by the control pulse generator 71 based on the detection pulse of the zero-cross detector 36. Thus, the full-wave rectified output waveform converted into the voltage is sampled by the sampling unit 72, the sampled value and the threshold value are compared by the comparison unit 63, and if it is below the threshold value, the charging stop unit 65 is controlled. . The control unit 21 is not provided with the reverse phase generation unit 31 and has the same configuration as shown in FIG.
In the second embodiment shown in FIG. 3, the sample values of the same sample phase for each phase of the three-phase power may be averaged by the storage / average unit 56 and the average value may be used.
[0022]
Embodiment 4
FIG. 5 shows a fourth embodiment of the present invention, in which parts corresponding to those in FIGS. 1, 3, and 6 are given the same reference numerals. This Embodiment 4 is a case where the opposite phase corresponding value is not used like the control unit 21 of the conventional apparatus shown in FIG. 6, and the output of the inverter 16 is input to the output value calculation unit 41 as in FIG. the control pulse from the control pulse generator 71, the effective value or average value is calculated as an output value for each period T _V in synchronization with the zero-cross point P _Z, error between the set value of the setting unit 42 and the output value The calculation is performed by the error calculation unit 43, and the correction unit 24 controls the reference value according to the error signal. As in the case shown in FIG. 1, the fluctuation amount of the error signal with respect to the error signal before one cycle T _V is detected by the fluctuation detecting unit 62, and when this fluctuation amount exceeds the threshold value, the charge stopping unit 65 controls the error signal. Is done.
[0023]
When using the anti-phase corresponding value, the area of each pulse width modulation signal is the same as shown in FIG. 9A, and the current capacity is not increased at the peak portion of the three-phase full-wave rectified output 28 without particularly increasing the power. The DC-DC converter 14 can be configured with small elements, and an inexpensive charging device can be obtained. Further, when control is performed so that the effective value (average value) of the output of the PWM generation unit 26 or the output of the inverter 16 becomes the set value, the charging is performed without a delay as in the control by the detection by the conventional current detection unit 19. The current can be controlled.
In each of the above-described embodiments, the inverter 16 is used for the DC-DC converter 14, but a chopper may be used.
[0024]
【The invention's effect】
As described above, according to the present invention, an open phase can be detected using a single transformer, and the overall structure can be reduced in size. In particular, when a negative phase corresponding value is used, a zero-cross detector used for the negative phase corresponding value processing can be used, and it is not necessary to provide a transformer for detecting a missing phase.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an example of a functional configuration according to a first embodiment of the invention.
FIG. 2A is a diagram illustrating an example of a full-wave rectified output waveform in a normal state and an open phase state, and B is a diagram illustrating an example of a control (error) signal in a normal state and an open phase state.
FIG. 3 is a diagram showing an example functional configuration of a second embodiment of the present invention.
FIG. 4 is a diagram showing an example functional configuration of a third embodiment of the invention.
FIG. 5 is a diagram showing a functional configuration example of a fourth embodiment of the present invention.
FIG. 6 is a diagram illustrating a functional configuration example of a conventional three-phase charging device.
FIG. 7 is a diagram showing a full-wave rectified output waveform and a reversed-phase waveform of the ripple.
FIG. 8 is a diagram illustrating an example of a functional configuration of a charging device using a negative phase correspondence value.
FIG. 9 is a diagram showing an example of a pulse width modulation signal.

Claims (2)

In a three-phase input charging device that performs full-wave rectification on input three-phase AC power using a full-wave rectifier circuit, and supplies the rectified output to a storage battery via a switching DC-DC converter for charging.
A zero-cross detector connected between two of the three power lines of the input three-phase AC power and detecting a zero-cross point of one inter-phase voltage;
An output value calculation unit that calculates an effective value or an average value of a charging current or a voltage to the storage battery as an output value for each one-third between adjacent zero cross points of the zero cross detection unit; ,
An error calculation unit for calculating an error between the output value and the set value as an error signal;
A correction unit for controlling the width of the switching signal with respect to the switching element of the switching DC-DC converter so that the error signal becomes zero;
A fluctuation detecting unit for detecting a fluctuation amount of the error signal for every third of the zero cross points with respect to the previous error signal;
A three-phase input charging device comprising: a charge stopping unit that stops the charging operation when the detected fluctuation amount exceeds a threshold value. In a three-phase input charging device that performs full-wave rectification on input three-phase AC power using a full-wave rectifier circuit, and supplies the rectified output to a storage battery via a switching DC-DC converter for charging.
A voltage converter for converting the full-wave rectified output into a voltage;
A zero-cross detector connected between two of the three power lines of the input three-phase AC power and detecting a zero-cross point of one inter-phase voltage;
A sampling unit that samples the output of the voltage conversion unit in synchronization with the detection zero cross point of the zero cross detection unit and every third of the adjacent zero cross points;
A three-phase input charging device comprising: a charge stopping unit that stops a charging operation when a sampling value of the sampling unit is equal to or less than a threshold value.

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