TWI463154B - Method and system for diagnosing power devices of charger - Google Patents

Description

Charging device detection system and method thereof

The present invention relates to a fault detection technique, and more particularly to a fault detection system and method for a charging device.

Today, when portable electronic products are widely used, charging devices have often become an indispensable electrical appliance for daily life.

In general, in order to achieve a variety of improvements in power factor and power output control, such as fixed voltage and fixed current, charging devices often employ high-efficiency bridgeless or interleaved control power architectures, and thus often require components such as diodes. The number of components, Insulated Gate Bipolar Transistor (IGBT) components, or metal-oxide-semiconductor field-effect transistor (MOSFET) components is quite large, and these types of components are damaged. The frequency is also relatively high.

When any of the components of the charging device is damaged, the charging device may not be charged or short-circuited. Therefore, it is preferable to know the state of each component before the charging operation is performed to ensure the safety of the charging device.

In the conventional technology for detecting failure of a charging device, it is common practice to directly remove each component from the charging device, and then perform short-circuit and open-circuit determination based on the cut-off voltage or conduction characteristics of each component. However, when the circuit in the charging device is more complicated due to demand and the number of components is increased, such a technique is quite time consuming.

The present invention provides a charging device detection system, comprising: a charging device comprising a plurality of diode elements and a plurality of power switching elements coupled to each other; and a detecting device coupled to the charging device and comprising: The converter is coupled to the charging device; a plurality of high frequency switching components are coupled to the first converter; a plurality of low frequency switching components are coupled to the plurality of diode components and the plurality of powers Between the switching elements; a plurality of voltage measuring devices coupled to the plurality of diode elements and the plurality of power switching elements, and obtaining a voltage between the plurality of diode elements and the plurality of power switching elements And the controller is coupled to the plurality of high frequency switching elements and the plurality of low frequency switching elements to output a switching control signal to the plurality of high frequency switching elements and the plurality of low frequency switching elements, and according to a judgment The voltage signal obtained by the plurality of voltage measuring devices is processed to detect an abnormality of each of the diode elements and each of the power switching elements in the charging device.

The invention provides a charging device detecting method, wherein the charging device is provided with a plurality of voltage measuring devices, comprising the following steps: (1) sequentially injecting a high frequency positive dynamic voltage signal and a high frequency negative dynamic voltage signal to the charging device. (2) when the voltage signal measured by the plurality of voltage measuring devices meets a predetermined value, a positive static voltage signal is injected into the charging device, and then the positive static voltage signal is maintained and the first modulation control signal is provided. Up to the charging device, injecting a negative quiescent voltage signal to the charging device, then maintaining the negative quiescent voltage signal and providing a second modulating control signal to the charging device; (3) measuring the plurality of voltage measuring devices When the voltage signal arrives at a predetermined value, the static voltage signal is injected and different modulation control signals are sequentially provided. And a plurality of power switching elements in the charging device; and (4) maintaining the static voltage signal and providing the same modulation control signal when the voltage signal measured by the plurality of voltage measuring devices meets a predetermined value Up to two of the plurality of power switching elements, and then providing another identical modulation control signal to the other of the charging devices.

Compared with the prior art, the charging device detecting system and the method thereof have the self-detecting function, and only need to be coupled to the detecting device as a whole system in a general charging device, and the controller and the first converter can be used. And the first and second high frequency switching elements generate different detection currents to inject into the charging device, and change the circuit of the detection current in the charging device by the first and second low frequency switching elements, and the controller controls the voltage according to the determination rule The voltage signal obtained by the measuring device is processed, and the abnormality of each of the diode elements and the power switching element in the charging device can be detected.

The embodiments of the present invention will be described by way of example only, and those skilled in the art can readily appreciate the other advantages and advantages of the present invention. Of course, the invention may be embodied or applied by other different embodiments.

Referring to Figure 1, a circuit diagram of a charging device detection system of the present invention will be described.

The charging device detection system of the present invention mainly includes a charging device 1 (other than a dotted line frame) and a detecting device 2 (within a dotted line frame).

The charging device 1 includes a plurality of diode elements DP1, DP2, DN1, DN2, DBP, DBN, D1, D2, D3 and D4, and a plurality of power switching elements IBP, IBN, ID1, ID2, ID3, and ID4, such as an insulated gate bipolar transistor (IGBT) or a metal-oxide-semiconductor field-effect transistor (MOSFET). In detail, the charging device 1 shown in FIG. 1 is an AC/DC charging device having a boost type power factor correction circuit as a front stage structure, that is, includes a full bridge circuit 10.

The detecting device 2 mainly includes a first converter 21, a first high frequency switching element Sgp, a second high frequency switching element Sgn, a first low frequency switching element S1, a second low frequency switching element S2, a first voltage measuring unit 26, and a first The second voltage measuring device 27, the third voltage measuring device 28, the fourth voltage sensor 29 and the controller 25.

The first converter 21 is coupled to the charging device 1 and can be used to generate a detection current injected into the charging device 1 . As shown in Fig. 1, the first converter 21 can convert the external power supply DC 12V into +Vg and -Vg (about 15V).

The first high frequency switching element Sgp is coupled to the positive voltage terminal of the first converter 21, the second high frequency switching element Sgn is coupled to the negative voltage terminal of the first converter 21, and the first high frequency switching element Sgp and the second The high frequency switching element Sgn can be used to change the nature of the detected current, such as high frequency, low frequency, high voltage, low voltage, dynamic or static.

The first low frequency switching element S1 and the second low frequency switching element S2 are coupled to the plurality of diode elements DP1, DP2, DN1, DN2, DBP, DBN, D1, D2, D3 and D4 and a plurality of power switching elements IBP, IBN , between ID1, ID2, ID3 and ID4, can be used to change the loop of the detection current.

First voltage measuring device 26, second voltage measuring device 27, third voltage The measuring device 28 and the fourth voltage sensor 29 are coupled to the plurality of diode elements DP1, DP2, DN1, DN2, DBP, DBN, D1, D2, D3 and D4 and a plurality of power switching elements IBP, IBN, Between ID1, ID2, ID3 and ID4, it is possible to obtain a plurality of diode elements DN2, DBP, DBN, D1, D2, D3 and D4 and a plurality of power switching elements IBP, IBN, ID1, ID2, ID3 and ID4 Voltage signals VDP, VDN, Vs and Vdc.

The controller 25 is coupled to the first and second low frequency switching elements S1 and S2 and the first and second high frequency switching elements Sgp and Sgn, and can output a low frequency switching control signal to control the first and second low frequency switching elements S1 and S2, And outputting a high frequency switching control signal to control the first and second high frequency switching elements Sgp and Sgn, and to the first voltage measuring device 26, the second voltage measuring device 27, and the third voltage measuring device 28 according to the determining rule. The voltage signals VDP, VDN, Vs, and Vdc obtained by the fourth voltage sensor 29 are processed to detect the diode elements DP1, DP2, DN1, DN2, DBP, DBN, D1, D2 in the charging device 1. D3 and D4 and each power switching element IBP, IBN, ID1, ID2, ID3 and ID4 are abnormal.

In FIG. 1, the charging device detection system of the present invention further includes a first current limiting circuit unit 23 and a second current limiting circuit unit 24. The first current limiting circuit unit 23 is coupled to the first high frequency switching element Sgp and the second high frequency switching element Sgn, and the second current limiting circuit unit 24 is coupled to the ground of the first converter 21. In other words, one end of the first high frequency switching element Sgp is coupled to the positive voltage terminal of the first converter 21, and the other end of the first high frequency switching element Sgp is coupled to the first current limiting circuit unit 23; one end of the second high frequency switching element Sgn is coupled to The negative terminal of the first converter 21 is coupled to the second current limiting circuit unit 24 at the other end.

In addition, the first voltage measuring device 26 is coupled to the first current limiting circuit unit 23, the second voltage measuring device 27 is coupled to the second current limiting circuit unit 24, and the positive voltage of the first voltage measuring device 26 is The terminal is coupled to the positive terminal of the second voltage measuring device 27, and the two ends of the third voltage measuring device 28 are coupled to the first current limiting circuit unit 23 and the second current limiting circuit unit 24, respectively.

In FIG. 1, the charging device detecting system of the present invention further includes a first resistive load RL1 connected in series with the first low frequency switching element S1 and a second resistive load RL2 connected in series with the second low frequency switching element S2. One end of the first low frequency switching element S1 is coupled to the positive voltage terminals of the first voltage measuring device 26, the second voltage measuring device 27 and the fourth voltage measuring device 29.

In the first embodiment, the charging device detection system of the present invention further includes a second converter 22 coupled to the controller 25 for generating an operating power supply to the controller 25, that is, converting the external power supply DC 12V into a working power supply Vcc. (about 3~5V).

The controller 25, the first converter 21, the first high frequency switching element Sgp, and the second high frequency switching element Sgn shown in FIG. 1 cooperate with the first current limiting circuit unit 23 and the second current limiting circuit unit 24 Generating different detection currents to detect the diode elements DP1, DP2, DN1, DN2, DBP, DBN, D1, D2, D3 and D4 and the power switching elements IBP, IBN, ID1, ID2, ID3 in the charging device 1 and ID4. In addition, the controller 25 outputs a low frequency control signal to control the first low frequency switching element S1 and the second low frequency switching element S2 so that the detection current can pass through different loops and the voltage signals VDP, VDN, Vs and Vdc according to the judgment rule. Processing, and further knowing the diode elements DP1, DP2, DN1, DN2, DBP, DBN, D1, D2, D3 and D4 and power switching elements IBP, IBN, ID1, ID2, ID3 and ID4 are abnormal.

Next, please refer to FIG. 2, which shows a flow chart of the method for measuring the charging device of the present invention.

The charging device detecting method of the present invention can be roughly classified into a first stage, a 2-1 to 2-2 stage, a third stage, a 4-1 to 4-4 stage, and a 4th to 4th to 4th stage. The charging device to which it is applied has a plurality of diode elements, a power switching element, and a voltage measuring device.

In the first stage S100, a static voltage signal is input to the charging device (described in detail in FIG. 3), and then in step S101, if the voltage signal measured by the voltage measuring device satisfies a predetermined value (by When the specific judgment rule is calculated, that is, Vdc(tm11)≧α and Vdc(tm12)≧α, the process proceeds to the stage 2-1~2-2 S200; otherwise, the table 1 is inquired to know where the short circuit occurs.

In the S200 of the 2-1~2-2 phase, the high frequency positive dynamic voltage signal and the high frequency negative dynamic voltage signal are sequentially injected into the charging device (described in detail in FIG. 5), and then in step S201, When the voltage signal measured by the voltage measuring device satisfies a predetermined value (calculated by a specific judgment rule), that is, when the code ABCD=1111, the process proceeds to the third stage S300; otherwise, the inquiry table 2 is used to know the charging. Anomalies in individual diode elements or power switching elements in a full bridge circuit in the device.

In the third stage S300, a positive static voltage signal is injected into the charging device, and then the positive static voltage signal is maintained and a first modulation control signal is supplied to the charging device, and a negative static voltage signal is injected into the charging device. Then maintaining the negative static voltage signal and providing a second modulation control signal to the charging device (described in detail in FIG. 7), and then in step S301, if the voltage signal measured by the voltage measuring device meets the predetermined condition When the value (calculated by the specific judgment rule), that is, the code Q1Q2Q3Q4=1111, the process proceeds to the stage 4-1~4-2 S400; otherwise, the query table 3 is used to know each of the boost circuits in the charging device. Abnormality of component (diode component or power switching component).

In the S400 of the 4-1~4-4 stage, the static voltage signal is injected and different modulation control signals are sequentially supplied to the plurality of power switching elements in the charging device (described in detail in FIG. 9), and then In step S401, if the voltage signal measured by the voltage measuring device satisfies the satisfied value (calculated by a specific judgment rule), that is, when the code is EFGH=2222, the process proceeds to the 4-5~4-6. Stage S500; otherwise, look up Table 4-1 to know which of the power switching elements ID1, ID2, ID3, ID4 is abnormal.

In stage 4-5~4-6 S500, maintaining the static voltage signal and providing the same modulation control signal to both of the plurality of power switching elements, and then providing another identical modulation control signal to The other two of the charging devices (described in detail in FIG. 10), and then in step S501, if the specific determination rule is satisfied, that is, the code MN=11, the diagnosis is ended; otherwise, the inquiry table 4-2 is known. Which of the power switching elements ID1, ID2, ID3, ID4 or diode elements D1, D2, D3, D4 is abnormal.

When step S301 and step S501 are satisfied, it indicates that the charging device is normal.

The following is a description of the first stage S100 in the third, fifth, seventh, ninth and tenth figures. Stages 2-1 to 2-2, S200, Stage 3, S300, Stages 4-1 to 4-4, S400, and Stages 4-4 to 4-5, S500. It should be noted that the first stage S100 is an optional step.

Referring to Fig. 3, there is shown a flow chart of the first stage of the charging device detecting method of the present invention. In step S11, a static voltage signal is injected into the charging device to determine whether there is a short circuit. In steps S12 and S13, it is determined whether the voltage signals Vdc(tm11) and Vdc(tm12) are smaller than α, wherein Vdc(tm11) is the voltage signal of the first signal measurement time point of the first stage, and Vdc(tm12) is the first The second time signal of the first stage measures the time point, and α is a voltage value slightly smaller than Vg, and the detailed timing and voltage signal diagram of the first stage are as shown in FIG.

In Fig. 3, if Vdc(tm11) is smaller than α and Vdc(tm12) is not smaller than α, there is an error of code 11; if Vdc(tm11) is not smaller than α and Vdc(tm12) is smaller than α, there is code 12 Error; if Vdc(tm11) is less than α and Vdc(tm12) is less than α, there is an error of code 13. Looking at Table 1, it can be seen where there is a short circuit in the charging device.

Please refer to FIG. 5, which is a flow chart of stages 2-1 to 2-2 of the charging device detecting method of the present invention. In step S21, a high frequency positive voltage signal is injected into the full bridge circuit of the charging device to diagnose an abnormality of each component in the full bridge circuit. Then, by | Vdc ( tm 21) - 2 | VsF ( tm 21) | | < δ of step S22, | VDPF ( tm 21) - 1/4 Vdc ( tm 21) | < δ of step S23, step S24 VDPF ( tm 21)-1/2 Vdc ( tm 21)|<δ, step S25 | VDNF ( tm 21)-3/4 Vdc ( tm 21)|<δ, step S26 | VDNF ( tm 21) - 1/2 Vdc ( tm 21)|<δ, step S27 | Vdc ( tm 21)-| VsF ( tm 21)||<δ, step S28 | VDPF ( tm 21)|<δ, step S29 | After VDNF ( tm 21)- Vdc ( tm 21) < δ, look up Table 2 to find the value of the code ABCD, and then determine the abnormality of each component.

Furthermore, in step S21', a high frequency negative voltage signal is injected into the full bridge circuit of the charging device to diagnose an abnormality of each component in the full bridge circuit. Then, by | Vdc ( tm 22)-2| VsF ( tm 22)||<δ, step S23' | VDNF ( tm 22)-1/4 Vdc ( tm 22)|<δ, step by step S22'S24'| VDNF ( tm 22)-1/2 Vdc ( tm 22)|<δ, step S25' | VDPF ( tm 22)-3/4 Vdc ( tm 22)|<δ, step S26'| VDPF ( tm 22)-1/2 Vdc ( tm 22)|<δ, step S27' | Vdc ( tm 22)-| VsF ( tm 22)||<δ, step S28' | VDNF ( tm 22) |<δ, step S29' | VDPF ( tm 22) - Vdc ( tm 22)|<δ After the judgment, the table 2 is queried to know the value of the code ABCD, and then the abnormality of each element is judged. δ is a small voltage difference, which is used to determine whether the arbitrary two voltage signals are consistent with the allowable difference, and VsF is the low-frequency filtered voltage signal Vs. The VDPF is the low-frequency filtered voltage signal VDP, and the VDNF is low-frequency filtered. Voltage signal VNP. The timing and voltage signal diagrams of stages 2-1~2-2 are shown in Figure 6.

Please refer to FIG. 7, a flow chart of the third stage of the charging device detecting method of the present invention.

Step S31, injecting a positive static voltage signal to the charging device; step S32, | Vdc ( tm 31) - | VsF ( tm 31) | | > ε 1; step S33, maintaining the positive static voltage signal and providing the first Pulse Width Modulation (PWM) control signal to power switching element IBP; step S34, ( Vdc ( tm 31) - Vdc ( tm 32)) > ε 2 judgment; step S35, | Vdc ( tm 32) - Gb 1. | VsF ( tm 32)||<determination of δ; step S36, injecting a negative quiescent voltage signal to the charging device; step S37, | Vdc ( tm 33)-| VsF ( tm 33)||> ε 1 judgment; S38, maintaining the negative quiescent voltage signal and providing a second PWM control signal to the power switching element IBN; step S39, ( Vdc ( tm 33) - Vdc ( tm 34)) > ε 2; and step S40, | Vdc ( Tm 34)- Gb 2. | VsF ( tm 34) | | < δ judgment, look up Table 3 to know the value of the code Err, and then know the abnormality of each component in each boost circuit. ε 1 is a voltage value slightly smaller than the bias voltage of the diode element (about 0.7 V), ε 2 is a small voltage difference, and Gb1 is when the boost circuit is controlled by the first PWM control signal. The ratio of the output voltage signal Vdc to VsF, and Gb2 is the ratio of the voltage signals Vdc and VsF output when the boost circuit is controlled by the first PWM control signal. The timing and voltage signal diagram of Phase 3 is shown in Figure 8.

Referring to Fig. 9, there is shown a flow chart of stages 4-1 to 4-4 of the charging device detecting method of the present invention. In step S41, a static voltage is injected to the charging device and a third PWM control signal is supplied to the power switching element ID1; in step S42, it is determined whether | Vdc ( tm41 )| is smaller than β; in step S43, a static voltage is injected to The charging device provides a fourth PWM control signal to the power switching element ID2; in step S44, it is determined whether |Vdc ( tm 42)| is less than β; in step S45, a static voltage is injected to the charging device and a fifth PWM control signal is provided. To the power switching element ID3; in step S46, it is determined whether |Vdc ( tm 43)| is smaller than β; in step S47, the static voltage is injected to the charging device and the sixth PWM control signal is supplied to the power switching element ID4; in step S48 In the judgment, if Vdc ( tm 44)| is smaller than β, the value of the code EFGH can be known through steps S41 to S48, and then the inquiry table 4-1 can know which of the power switching elements ID1, ID2, ID3, and ID4 is abnormal.

Referring to Fig. 10, there is shown a flow chart of stages 4-5 to 4-6 of the charging device detecting method of the present invention. In step S49, a static voltage is injected to the charging device and a seventh PWM control signal is supplied to the power switching elements ID1 and ID3; in step S50, it is determined whether | Vdc ( tm 45)| is smaller than β; in step S51, | Vb ( tm 45)- Gd 1. Whether Vdc ( tm 45)| is smaller than δ; in step S52, a static voltage is injected to the charging device and an eighth PWM control signal is supplied to the power switching elements ID2 and ID4; in step S53, it is determined whether | Vdc ( tm 46)| Less than β; in step S54, it is judged that | Vb ( tm 46)- Gd 2. Whether Vdc ( tm 46)| is less than δ. The value of the code MN can be known by S49 to S54, and then the lookup table 4-2 can know which of the power switching elements ID1, ID2, ID3 and ID4 or the diode elements D1, D2, D3 and D4 are abnormal.

β is a voltage value slightly smaller than Vg, and δ is a small voltage difference value, which is used to determine whether the tolerance difference of any two voltage signals is consistent, and Gd1 is when the third PWM control signal is turned on to the rear stage of the charging device. The ratio of the output voltage signal Vb to the voltage signal Vdc, Gd2, Gd3, and Gd4 can be analogized, and the ratio is related to the second resistive load RL2. The timing and voltage signal diagrams of stages 4-1~4-4 and 4-5~4-6 are shown in Figure 11.

In summary, the charging device detection system and method thereof of the present invention can generate different detection currents by the controller, the first converter, the first and second high frequency switching elements to inject the charging device, and And a second low frequency switching component to change a loop of the detection current in the charging device, and the controller processes the voltage signal obtained by the voltage measuring device according to the determining rule, and can detect each diode component in the charging device and Whether the power switching element is abnormal. Therefore, the charging device detecting system and the method thereof of the present invention do not need to remove each component from the charging device to detect which component is faulty or which circuit is short-circuited or open circuit one by one, and can self-detect through some judgment rules.

The above embodiments are merely illustrative of the principles and effects of the invention and are not intended to limit the invention. Modifications and variations of the above-described embodiments can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention should be as set forth in the scope of the claims described below.

1‧‧‧Charging device

10‧‧‧Full bridge circuit

2‧‧‧Detection device

21‧‧‧ first converter

22‧‧‧Second converter

23‧‧‧First current limiting circuit unit

24‧‧‧Second current limiting circuit unit

25‧‧‧ Controller

26‧‧‧First voltage measuring device

27‧‧‧Second voltage measuring device

28‧‧‧ Third voltage measuring device

29‧‧‧ Fourth voltage measuring device

DP1, DP2, DN1, DN2, DBP, DBN, D1, D2, D3, D4‧‧‧ diode components

IBP, IBN, ID1, ID2, ID3, ID4‧‧‧ power switching components

Sgp‧‧‧1st high frequency switching element

Sgn‧‧‧Second high frequency switching element

S1‧‧‧First low frequency switching element

S2‧‧‧ second low frequency switching element

RL1‧‧‧First resistance load

RL2‧‧‧second resistive load

S100, S200, S300, S400, S500‧‧‧

S101, S201, S301, S401, S501, S11~S13, S21~S29, S21'~S29', S31~S40, S41~S54‧‧

1 is a circuit diagram of a charging device detecting system of the present invention; FIG. 2 is a flow chart showing a charging device detecting method of the present invention; and FIG. 3 is a flow chart showing a first stage of the charging device detecting method of the present invention; The figure shows the timing and voltage signal diagram of the first stage of the charging device detecting method of the present invention; and FIG. 5 is a flow chart of the 2-1~2-2 stage of the charging device detecting method of the present invention; 6 is a timing and voltage signal diagram of stages 2-1 to 2-2 of the charging apparatus detecting method of the present invention; and FIG. 7 is a flowchart showing the third stage of the charging apparatus detecting method of the present invention; FIG. The timing and voltage signal diagram of the third stage of the charging device detecting method of the present invention; FIG. 9 is a flow chart showing stages 4-1 to 4-4 of the charging device detecting method of the present invention; and FIG. 10 shows the present invention. The flowchart of the fourth to fourth stages of the charging device detecting method; and the eleventh drawing showing the stages 4-1 to 4-4 and the fourth to fourth to fourth stages of the charging device detecting method of the present invention Timing and voltage signal diagram.

1‧‧‧Charging device

10‧‧‧Full bridge circuit

2‧‧‧Detection device

21‧‧‧ first converter

22‧‧‧Second converter

23‧‧‧First current limiting circuit unit

24‧‧‧Second current limiting circuit unit

25‧‧‧ Controller

26‧‧‧First voltage measuring device

27‧‧‧Second voltage measuring device

28‧‧‧ Third voltage measuring device

29‧‧‧ Fourth voltage measuring device

D1, D2, D3, D4‧‧‧ diode components

DBN, DBP, DN1, DN2, DP1, DP2‧‧‧ diode components

IBP, IBN, ID1, ID2, ID3, ID4‧‧‧ power switching components

Sgp‧‧‧1st high frequency switching element

Sgn‧‧‧Second high frequency switching element

S1‧‧‧First low frequency switching element

S2‧‧‧ second low frequency switching element

RL1‧‧‧First resistance load

RL2‧‧‧second resistive load

Claims (10)

A charging device detecting system includes: a charging device comprising a plurality of diode elements and a plurality of power switching elements coupled to each other; and a detecting device coupled to the charging device, comprising: a first converter, The plurality of high frequency switching elements are coupled to the first converter; the plurality of low frequency switching elements are coupled to the plurality of diode elements and the plurality of power switching elements And a plurality of voltage measuring devices coupled to the plurality of diode elements and the plurality of power switching elements, and obtaining voltage signals between the plurality of diode elements and the plurality of power switching elements; The controller is coupled to the plurality of high frequency switching elements and the plurality of low frequency switching elements to output a switching control signal to the plurality of high frequency switching elements and the plurality of low frequency switching elements, and according to a determination rule The voltage signals obtained by the plurality of voltage measuring devices are processed to detect abnormalities of the two diode elements and each of the power switching elements in the charging device. The charging device detecting system of claim 1, wherein the plurality of high frequency switching elements comprise a first high frequency switching element and a second high frequency switching element, the first high frequency switching element being coupled to a positive voltage terminal of the first converter, the second high frequency switching component is coupled At the negative voltage end of the first converter. The charging device detecting system of claim 2, further comprising a first current limiting circuit unit and a second current limiting circuit unit, wherein the first current limiting circuit unit and the first high frequency switching component and the The second high frequency switching element is coupled, and the second current limiting circuit unit is coupled to the ground end of the first converter. The charging device detecting system of claim 3, wherein the plurality of voltage measuring devices comprise a first voltage measuring device and a second voltage measuring device, and wherein the first voltage measuring device is And coupled to the first current limiting circuit unit, the second voltage measuring device is coupled to the second current limiting circuit unit, and the positive voltage terminal of the first voltage measuring device and the second voltage measuring device The positive pressure terminals are coupled to each other. The charging device detection system of claim 3, wherein the plurality of voltage measuring devices further comprise a third voltage measuring device, wherein the two ends of the third voltage measuring device are respectively coupled to the first limit a stream circuit unit and the second current limiting circuit unit. The charging device detecting system of claim 4, further comprising a first resistive load and a second resistive load, and the low frequency switching component comprises a first low frequency switching component and a second low frequency switching component, wherein the first One end of the low frequency switching component is coupled to the positive voltage terminals of the first and second voltage measuring devices, the other end of the first low frequency switching component is connected in series with the first resistive load, and the second low frequency switching component is coupled to the first The second resistive load is connected in series. A charging device detecting system according to claim 6 of the patent application, The plurality of voltage measuring devices further comprise a fourth voltage measuring device, and the two ends of the fourth voltage measuring device are respectively coupled to the first low frequency switching component and the first resistive load. The charging device detecting system of claim 1, further comprising a second converter coupled to the controller for generating an operating power supply to the controller. A charging device detecting method, wherein the charging device is provided with a plurality of voltage measuring devices, comprising the steps of: (1) sequentially injecting a high frequency positive dynamic voltage signal and a high frequency negative dynamic voltage signal to the charging device; (2) When the voltage signal measured by the plurality of voltage measuring devices satisfies a determination rule, a positive static voltage signal is injected into the charging device, and then the positive static voltage signal is maintained and the first modulation control signal is supplied to the charging And charging a negative static voltage signal to the charging device, then maintaining the negative static voltage signal and providing a second modulation control signal to the charging device; and (3) measuring the voltage measured by the plurality of voltage measuring devices When the signal satisfies another judgment rule, the static voltage signal is injected and the different modulation control signals are sequentially supplied to the plurality of power switching elements in the charging device; and (4) the plurality of voltage measuring devices measure When the voltage signal satisfies another determination rule, the static voltage signal is maintained and the same modulation control signal is supplied to both of the plurality of power switching elements, and then For another identical modulation control signal to the charging device The other two of the set. The method for detecting a charging device according to claim 9 includes, before step (1), injecting another static voltage signal to the charging device, and the voltage signal measured by the plurality of voltage measuring devices is satisfied. When the rule is judged again, proceed to step (1).