Taking a pure electric vehicle as an example, this paper introduces the necessity of pre-charging process to alleviate the impact of high-voltage system and improve the safety of the whole vehicle, and elaborates the parameter changes and basis in the pre-charging process, combined with practical experience to provide a reference solution to avoid risks, and finally through the test to prove the feasibility of the method.

The energy crisis and environmental pollution are increasing day by day. In terms of energy consumption and environmental pollution, the impact of automobiles cannot be ignored. The development of clean electric vehicles with high efficiency, energy saving, low noise and zero emission has become an inevitable trend in the development of automobile industry at home and abroad. In order to improve the power and energy utilization of electric vehicles, the voltage of the power battery is getting higher and higher, from the original tens of volts to the current hundreds of volts, so it is necessary to equip a special system to manage the safety of the high-voltage system. In electric vehicles, not only need to be equipped with a special on-board high-voltage safety management system, but also a special safety test system should be designed to monitor the on-board high-voltage safety management system for irregular safety monitoring.

According to the safety standards of electric vehicles and human body, under the conditions that the maximum AC working voltage is less than 660V, the maximum DC working voltage is less than 1000 VIP and the vehicle mass is less than 3 500kg, the high voltage safety requirements of electric vehicles are as follows:

① The safe voltage of human body is lower than 35V, and the maximum value of the product of electric shock current and duration is less than 30Ma · s;

The insulation resistance divided by the rated voltage of the battery should be at least greater than 1000 D/V, it is best to ensure greater than 500 Ω/V;

③ The power-on process of the high-voltage system higher than 60 V needs at least 100 ms, and the pre-charging process should be used to avoid high-voltage impact during the power-on process;

④ In any case, the relay disconnection time should be less than 20 ms. When the high-voltage system is disconnected, the peak value of the ground voltage of any conductive part and accessible part of the car should be less than 42.4V (AC) or 60 V (DC), The stored energy should be less than 20J.

According to the above safety requirements, pre-charge management is an indispensable and important link in new energy vehicles. Among them, the main function of electric vehicle pre-charge is to charge the large capacitor of the motor controller (ie inverter) to reduce the contactor Spark arcing when in contact reduces impact and increases safety. A physical diagram of an inverter is shown in Figure 1.

　　

 

For the judgment of pre-charge completion, the pre-charge control strategy research of the existing technology is basically divided into three types:

① Collect the DC bus current of the motor controller, and output the pre-charging completion signal when the DC bus current is close to 0A;

② Collect the voltage of the on-board power battery and the voltage of the motor controller respectively, and then compare the two voltage values. When the two voltages tend to be equal, the pre-charge completion signal is output. This method is adopted in this paper. When the voltage value reaches 90% of the power battery voltage, it is considered that the pre-charge is completed;

③ Collect the DC bus voltage of the motor controller. When the DC bus voltage reaches the set undervoltage protection point, after a delay, the pre-charge completion signal is output. Due to the deviation of current sensor and voltage and current sampling accuracy, consistency of on-board power supply management system, device stability and other problems, the actual pre-charging may not be completed when the controller outputs the pre-charging completion signal, resulting in a voltage difference between the on-board power battery and the pre-charging capacitive DC bus, which does not eliminate the risk of instantaneous high current impact, affecting the safety and reliability of the motor controller, or the actual pre-charging may have already been completed when the pre-charging signal is output, resulting in reducing the control rate. Therefore, in the pre-charging process, it is particularly important to monitor the changes of various parameters to determine the completion of pre-charging, failure, etc.

1 No pre-charge analysis

Taking the battery, battery management system, motor controller and pre-charging system of a two-compartment pure electric vehicle as an example, the power battery system of the vehicle consists of 9 and 102 series of lithium iron phosphate cells connected in series, with the cell specification of 36 800 MP (3.2V 6.5 Ah) and the capacitor capacity C = 0 000 μF. the simplified pre-charging structure is shown in fig. 2.

　　

 

As shown in fig. 2, the front end of the motor controller load carried by the battery has a large capacitor c. during cold start, there is no charge on c or only a very low residual voltage. When there is no precharge, the main relays K and K_are directly connected to C. At this time, the battery voltage Yao has a high voltage of 326.4V, while the voltage on the load capacitor C is close to 0, which is equivalent to an instantaneous short circuit. The load resistance is only the resistance of the wire and the relay contact, which is generally far less than 20 mΩ. According to Ohm's law, the loop resistance is calculated by 20 mΩ, the UB-Uc pressure difference is calculated by 326.4V, and the instantaneous current I = 326.4/0.02 = 16320A. Relay K and K_will undoubtedly be damaged.

Taking a pure electric vehicle as an example, this paper introduces the necessity of pre-charging process to alleviate the impact of high-voltage system and improve the safety of the whole vehicle, and elaborates the parameter changes and basis in the pre-charging process. On this basis, it puts forward the parameters such as monitoring voltage rise rate and current change rate to carry out safety management on the pre-charging process, and pre-judge whether there is leakage, insulation and resistance loss in the pre-charging process.

3 is a pre-charge process waveform. After adding the pre-charging process, K + is turned off first, so that the pre-charging loop composed of KP and R with larger impedance is turned on first. When the pre-charging circuit works, the voltage Uc on the load capacitor C is getting higher and higher (the pre-charging current IP =(UB-Uc)/R is getting smaller and smaller). When approaching the battery voltage Yao (I .e. △U in fig. 3 is small enough, generally less than 10% of the play), the pre-charge relay KP is switched off and the main relay K + is switched on, so that there is no large current impact. Because the UB-Uc is small at this time, the current is small.

　　

 

Generally, the pre-charge resistance range is 20- 100Ω, and R = 25Ω is selected for this project. Ub and the voltage difference are still calculated at 326.4V. At the moment of switching on, the maximum current Ip = 326.4/25=13.056 A flowing through the pre-charge circuit and entering the capacitor C. At this time, the pre-charge relay capacity 15A is selected, the pre-charge circuit is safe, and at the same time, it can ensure that there is no impact current when K is closed.

The above circuit to do a first-order circuit zero-state response equivalent analysis, you can get Uc, Ip as follows.

　　

 

In the formula: τ ------ time constant of RC circuit, τ = RC.

From the theoretical formula, it is known that Uc and IP should conform to certain change rules and characteristics in the pre-charging process. At the same time, the pre-charging is combined by the battery and the external load. The two conditions will affect the pre-charging process. Therefore, by monitoring the changes of Uc and IP in the pre-charging process, it is detected whether the pre-charging process is successful, whether there is a fault and the fault type.

1) Voltage Uc growth rate is slower than expected Uc, IP growth rate is greater than expected I.

Fault 1: insulation fault. The load has a short circuit or a small resistive load due to a fault, such as capacitor breakdown, etc., which will cause Uc to never go up during the pre-charging process (the voltage always drops on the pre-charging resistor R). At this time, if the current is too large, the heat release of the pre-charge resistor will increase, and the ordinary pre-charge resistor will burn out. The thermistor with PTC effect of Huaju Electronics will play a protective role and reach a high resistance state, thus limiting the current and protecting the equipment. At the same time, the pre-charging process fails, the main relay cannot be turned on, and the subsequent work cannot be carried out. At this time, the pre-charging circuit current will flow into the low-voltage electrical network of the vehicle, and there is a hidden danger of direct contact with the occupants. Therefore, in the case of a confirmed fault, the pre-charging circuit should be quickly disconnected, and the vehicle is prohibited from driving on power before professional maintenance and inspection. The self-protection thermistor of Huagu Electronics can effectively avoid this situation. When the fault has a short circuit or a small resistive load, the protection performance of the pre-charge resistor of Huagu Electronics will be brought into play, and the pre-charge resistor of Huagu Electronics will become a high resistance state, limiting the current to a few milliamperes to protect the low-voltage electrical network of the whole vehicle behind.

Fault 2: RC becomes larger. In the design or installation process, errors will cause improper matching; in use, due to time, environment and other factors, the electrode corrosion of the capacitor, dielectric electrical aging and thermal aging, self-healing effect and other failures will affect the parameter change of C; The increase in the contact resistance of the wire and the wire and the electrode will cause the R value to change.

2) The voltage growth rate is faster than expected, the maximum speed is greater than expected I or equal to 0.

Fault 1: open circuit, open circuit. The false precharge is completed due to the open circuit of the load. The possible reasons are that the load is not wired or the capacitor is broken due to fault, such as oxidation and poor contact between the contact surface of the lead wire and the electrode, resulting in low-level open circuit. The liquid electrolyte dries up or freezes, etc. At this time, the Uc detected by BMS through the output port is not the voltage on the real load capacitor, but the open circuit voltage (OCV) of the battery pack, and the false Uc = UB information is immediately obtained, which may lead to the end of precharging and the direct connection of the main relay, but there is no danger because the output is open. However, if the load is suddenly applied at this time, because the pre-charging has ended, the resistor R of the non-pre-charging circuit limits the current, which will generate a large current and damage the circuit or relay. Therefore, in a general precharge strategy, what is completed as soon as it is powered on can be judged as a fault and subsequently prohibited. In this case, the problem can be determined by querying the conduction of the precharge loop.

Fault 2 ; RC becomes smaller. In the design or installation process, errors will cause improper matching; the capacitor in the process of use with silver ion migration, dielectric molecular structure changes, high humidity or low pressure environment between the electrode arc and other reasons caused by the parameter value of C becomes smaller, affecting the pre-charge results.

In order to avoid the occurrence of pre-charge failure, when selecting each component, automobile-grade products should be selected first, and industrial-grade products are not applicable; some parts that are easy to insulation failure and easy to touch should be added with additional protection measures on the premise of existing insulation protection, so as to reduce the damage to the circuit caused by wear and man-made reasons and reduce the failure rate.

3 Test performance

4 is a circuit of a voltage detection module. From Figure 4, the following formula can be derived

　　

 

In the formula: Uo-voltage value collected by single chip microcomputer; Uz-total voltage value of battery pack, R20, R21, R22, R23, R24-voltage dividing resistor, ft3-magnification.

　　

 

Verify on the above test vehicle, change the RC value and insulation characteristics, and the test results are shown in Table 1.

　　

 

4 Conclusions

The development of electric vehicles and hybrid vehicles is an inevitable trend, but in order to improve energy efficiency and enhance system power, most of the power battery systems are high-voltage at this stage, which poses a hidden danger to the safety of drivers and passengers. Therefore, in the high-voltage design process, adding pre-charge management is an inevitable requirement of regulations and safety design. In the design process, reasonable detection methods and strategies can not only judge whether the pre-charging process is successful, but also judge the charging failure before the vehicle starts, identify the type and location of the fault that may occur, reduce the safety management pressure of the battery management system and the vehicle controller, improve the safety of the vehicle, and promote the promotion of the new energy vehicle industry as soon as possible.

Accessories Huaju Electronic Charging Resistor Model

1. Main technical parameters

Model	Zero power resistor R25	Maximum voltage		Heat capacity	Maximum non-actuating energy			Working temperature
	(Ω)	Vmax		Cth(J/K)	ENon(J)			(℃)
		(Vac)	VDC		25℃	40℃	60℃
Power frequency voltage 260Vac
MZFLY-07D120T70RH-260	70	260	370	0.15	14	12	9	-55～ 85
MZFLY-07D120T80RH-260	80	260	370	0.15	14	12	9
MZFLY-07D120T101RH-260	100	260	370	0.15	14	12	9
MZFLY-07D120T121RH-260	120	260	370	0.15	14	12	9
MZFLY-07D120T151RH-260	150	260	370	0.15	14	12	9
MZFLY-07D120T201RH-260	200	260	370	0.15	14	12	9
MZFLY-07D120T251RH-260	250	260	370	0.15	14	12	9
MZFLY-07D120T401RH-260	400	260	370	0.15	14	12	9
MZFLY-07D120T501RH-260	500	260	370	0.15	14	12	9
MZFLY-07D120T102RH-260	1000	260	370	0.15	14	12	9
MZFLY-08D120T70RH-260	70	260	370	0.3	28	24	18
MZFLY-08D120T80RH-260	80	260	370	0.3	28	24	18
MZFLY-08D120T101RH-260	100	260	370	0.3	28	24	18
MZFLY-08D120T121RH-260	120	260	370	0.3	28	24	18
MZFLY-08D120T151RH-260	150	260	370	0.3	28	24	18
MZFLY-08D120T201RH-260	200	260	370	0.3	28	24	18
MZFLY-08D120T251RH-260	250	260	370	0.3	28	24	18
MZFLY-08D120T401RH-260	400	260	370	0.3	28	24	18
MZFLY-08D120T501RH-260	500	260	370	0.3	28	24	18
MZFLY-08D120T102RH-260	1000	260	370	0.3	28	24	18
MZFLY-09D120T70RH-260	70	260	370	0.4	38	32	24
MZFLY-09D120T101RH-260	100	260	370	0.4	38	32	24
MZFLY-09D120T121RH-260	120	260	370	0.4	38	32	24
MZFLY-09D120T151RH-260	150	260	370	0.4	38	32	24
MZFLY-09D120T201RH-260	200	260	370	0.4	38	32	24
MZFLY-09D251T251RH-260	250	260	370	0.4	38	32	24
MZFLY-09D501T501RH-260	500	260	370	0.4	38	32	24
MZFLY-09D120T102RH-260	1000	260	370	0.4	38	32	24
MZFLY-11D120T10RH-260	10	260	370	0.6	57	48	36
MZFLY-11D120T15RH-260	15	260	370	0.6	57	48	36
MZFLY-11D120T20RH-260	20	260	370	0.6	57	48	36
MZFLY-11D120T30RH-260	30	260	370	0.6	57	48	36
MZFLY-11D120T50RH-260	50	260	370	0.6	57	48	36
MZFLY-11D120T70RH-260	70	260	370	0.6	57	48	36
MZFLY-11D120T101RH-260	100	260	370	0.6	57	48	36
MZFLY-11D120T151RH-260	150	260	370	0.6	57	48	36
MZFLY-11D120T201RH-260	200	260	370	0.6	57	48	36
MZFLY-11D120T251RH-260	250	260	370	0.6	57	48	36
MZFLY-11D120T401RH-260	400	260	370	0.6	57	48	36
MZFLY-11D120T501RH-260	500	260	370	0.6	57	48	36
MZFLY-11D120T801RH-260	800	260	370	0.6	57	48	36
MZFLY-11D120T102RH-260	1000	260	370	0.6	57	48	36
MZFLY-14D120T6R0H-260	6	260	370	1.0	95	80	60
MZFLY-14D120T10RH-260	10	260	370	1.0	95	80	60
MZFLY-14D120T15RH-260	15	260	370	1.0	95	80	60
MZFLY-14D120T18RH-260	18	260	370	1.0	95	80	60
MZFLY-14D120T25RH-260	25	260	370	1.0	95	80	60
MZFLY-14D120T30RH-260	30	260	370	1.0	95	80	60
MZFLY-14D120T45RH-260	45	260	370	1.0	95	80	60
MZFLY-14D120T50RH-260	50	260	370	1.0	95	80	60
MZFLY-14D120T70RH-260	70	260	370	1.0	95	80	60
MZFLY-14D120T101RH-260	100	260	370	1.0	95	80	60
MZFLY-14D120T151RH-260	150	260	370	1.0	95	80	60
MZFLY-14D120T201RH-260	200	260	370	1.0	95	80	60
MZFLY-14D120T251RH-260	250	260	370	1.0	95	80	60
MZFLY-14D120T401RH-260	400	260	370	1.0	95	80	60
MZFLY-14D120T501RH-260	500	260	370	1.0	95	80	60
MZFLY-14D120T801RH-260	800	260	370	1.0	95	80	60
MZFLY-14D120T102RH-260	1000	260	370	1.0	95	80	60
MZFLY-18D120T6R0H-260	6	260	370	1.5	143	120	90
MZFLY-18D120T10RH-260	10	260	370	1.5	143	120	90
MZFLY-18D120T15RH-260	15	260	370	1.5	143	120	90
MZFLY-18D120T18RH-260	18	260	370	1.5	143	120	90
MZFLY-18D120T25RH-260	25	260	370	1.5	143	120	90
MZFLY-18D120T30RH-260	30	260	370	1.5	143	120	90
MZFLY-18D120T45RH-260	45	260	370	1.5	143	120	90
MZFLY-18D120T50RH-260	50	260	370	1.5	143	120	90
MZFLY-18D120T70RH-260	70	260	370	1.5	143	120	90
MZFLY-18D120T101RH-260	100	260	370	1.5	143	120	90
MZFLY-18D120T151RH-260	150	260	370	1.5	143	120	90
MZFLY-18D120T201RH-260	200	260	370	1.5	143	120	90
MZFLY-18D120T251RH-260	250	260	370	1.5	143	120	90
MZFLY-18D120T401RH-260	400	260	370	1.5	143	120	90
MZFLY-18D120T501RH-260	500	260	370	1.5	143	120	90
MZFLY-18D120T801RH-260	800	260	370	1.5	143	120	90
MZFLY-18D120T102RH-260	1000	260	370	1.5	143	120	90
MZFLY-20D120T6R0H-260	6	260	370	1.9	180	152	114
MZFLY-20D120T10RH-260	10	260	370	1.9	180	152	114
MZFLY-20D120T15RH-260	15	260	370	1.9	180	152	114
MZFLY-20D120T18RH-260	18	260	370	1.9	180	152	114
MZFLY-20D120T25RH-260	25	260	370	1.9	180	152	114
MZFLY-20D120T30RH-260	30	260	370	1.9	180	152	114
MZFLY-20D120T45RH-260	45	260	370	1.9	180	152	114
MZFLY-20D120T50RH-260	50	260	370	1.9	180	152	114
MZFLY-20D120T70RH-260	70	260	370	1.9	180	152	114
MZFLY-20D120T101RH-260	100	260	370	1.9	180	152	114
MZFLY-20D120T151RH-260	150	260	370	1.9	180	152	114
MZFLY-20D120T201RH-260	200	260	370	1.9	180	152	114
MZFLY-20D120T251RH-260	250	260	370	1.9	180	152	114
MZFLY-20D120T401RH-260	400	260	370	1.9	180	152	114
MZFLY-20D120T501RH-260	500	260	370	1.9	180	152	114
MZFLY-20D120T801RH-260	800	260	370	1.9	180	152	114
MZFLY-20D120T102RH-260	1000	260	370	1.9	180	152	114
MZFLY-22D120T3R3H-260	3.3	260	370	2.4	228	192	144
MZFLY-22D120T4R7H-260	4.7	260	370	2.4	228	192	144
MZFLY-22D120T6R0H-260	6	260	370	2.4	228	192	144
MZFLY-22D120T10RH-260	10	260	370	2.4	228	192	144
MZFLY-22D120T15RH-260	15	260	370	2.4	228	192	144
MZFLY-22D120T18RH-260	18	260	370	2.4	228	192	144
MZFLY-22D120T25RH-260	25	260	370	2.4	228	192	144
MZFLY-22D120T30RH-260	30	260	370	2.4	228	192	144
MZFLY-22D120T45RH-260	45	260	370	2.4	228	192	144
MZFLY-22D120T50RH-260	50	260	370	2.4	228	192	144
MZFLY-22D120T70RH-260	70	260	370	2.4	228	192	144
MZFLY-22D120T101RH-260	100	260	370	2.4	228	192	144
MZFLY-22D120T151RH-260	150	260	370	2.4	228	192	144
MZFLY-22D120T201RH-260	200	260	370	2.4	228	192	144
MZFLY-22D120T251RH-260	250	260	370	2.4	228	192	144
MZFLY-22D120T401RH-260	400	260	370	2.4	228	192	144
MZFLY-22D120T501RH-260	500	260	370	2.4	228	192	144
MZFLY-22D120T801RH-260	800	260	370	2.4	228	192	144
MZFLY-22D120T102RH-260	1000	260	370	2.4	228	192	144
MZFLY-27D120T3R3H-260	3.3	260	370	3.75	356	300	225
MZFLY-27D120T4R7H-260	4.7	260	370	3.75	356	300	225
MZFLY-27D120T6R0H-260	6	260	370	3.75	356	300	225
MZFLY-27D120T10RH-260	10	260	370	3.75	356	300	225
MZFLY-27D120T15RH-260	15	260	370	3.75	356	300	225
MZFLY-27D120T18RH-260	18	260	370	3.75	356	300	225
MZFLY-27D120T25RH-260	25	260	370	3.75	356	300	225
MZFLY-27D120T30RH-260	30	260	370	3.75	356	300	225
MZFLY-27D120T45RH-260	45	260	370	3.75	356	300	225
MZFLY-27D120T50RH-260	50	260	370	3.75	356	300	225
MZFLY-27D120T70RH-260	70	260	370	3.75	356	300	225
MZFLY-27D120T101RH-260	100	260	370	3.75	356	300	225
MZFLY-27D120T151RH-260	150	260	370	3.75	356	300	225
MZFLY-27D120T201RH-260	200	260	370	3.75	356	300	225
MZFLY-27D120T251RH-260	250	260	370	3.75	356	300	225
MZFLY-27D120T401RH-260	400	260	370	3.75	356	300	225
MZFLY-27D120T501RH-260	500	260	370	3.75	356	300	225
MZFLY-27D120T801RH-260	800	260	370	3.75	356	300	225
MZFLY-27D120T102RH-260	1000	260	370	3.75	356	300	225
Power frequency voltage 280Vac
MZFLY-14D115T25RH-280	25	280	400	1.1	100	82	60
MZFLY-14D115T50RH-280	50	280	400	1.1	100	82	60
MZFLY-14D115T80RH-280	80	280	400	1.1	100	82	60
MZFLY-18D130T22RH-280	22	280	400	1.6	168	152	112
MZFLY-18D130T33RH-280	33	280	400	1.6	168	152	112
MZFLY-20D130T22RH-280	22	280	400	2.1	220	200	147
MZFLY-20D130T33RH-280	33	280	400	2.1	220	200	147
Power frequency voltage 440Vac
MZFLY-09D120T70RH-440	70	440	620	0.5	47.5	40	30
MZFLY-09D120T101RH-440	100	440	620	0.5	47.5	40	30
MZFLY-09D120T121RH-440	120	440	620	0.5	47.5	40	30
MZFLY-09D120T151RH-440	150	440	620	0.5	47.5	40	30
MZFLY-09D120T201RH-440	200	440	620	0.5	47.5	40	30
MZFLY-09D251T251RH-440	250	440	620	0.5	47.5	40	30
MZFLY-09D501T501RH-440	500	440	620	0.5	47.5	50	30
MZFLY-09D120T102RH-440	1000	440	620	0.5	47.5	40	30
MZFLY-11D120T50RH-440	50	440	620	0.8	76	64	48
MZFLY-11D120T70RH-440	70	440	620	0.8	76	64	48
MZFLY-11D120T101RH-440	100	440	620	0.8	76	64	48
MZFLY-11D120T151RH-440	150	440	620	0.8	76	64	48
MZFLY-11D120T201RH-440	200	440	620	0.8	76	64	48
MZFLY-11D120T251RH-440	250	440	620	0.8	76	64	48
MZFLY-11D120T401RH-440	400	440	620	0.8	76	64	48
MZFLY-11D120T501RH-440	500	440	620	0.8	76	64	48
MZFLY-11D120T801RH-440	800	440	620	0.8	76	64	48
MZFLY-11D120T102RH-440	1000	440	620	0.8	76	64	48
MZFLY-14D115T121RH-440	120	440	620	1.4	126	105	77
MZFLY-14D115T151RH-440	150	440	620	1.4	126	105	77
MZFLY-14D120T30RH-440	30	440	620	1.4	133	112	84
MZFLY-14D120T45RH-440	45	440	620	1.4	133	112	84
MZFLY-14D120T50RH-440	50	440	620	1.4	133	112	84
MZFLY-14D120T70RH-440	70	440	620	1.4	133	112	84
MZFLY-14D120T101RH-440	100	440	620	1.4	133	112	84
MZFLY-14D120T151RH-440	150	440	620	1.4	133	112	84
MZFLY-14D120T201RH-440	200	440	620	1.4	133	112	84
MZFLY-14D120T251RH-440	250	440	620	1.4	133	112	84
MZFLY-14D120T401RH-440	400	440	620	1.4	133	112	84
MZFLY-14D120T501RH-440	500	440	620	1.4	133	112	84
MZFLY-14D120T801RH-440	800	440	620	1.4	133	112	84
MZFLY-14D120T102RH-440	1000	440	620	1.4	133	112	84
MZFLY-18D120T30RH-440	30	440	620	2.1	200	168	126
MZFLY-18D120T45RH-440	45	440	620	2.1	200	168	126
MZFLY-18D120T50RH-440	50	440	620	2.1	200	168	126
MZFLY-18D120T70RH-440	70	440	620	2.1	200	168	126
MZFLY-18D120T101RH-440	100	440	620	2.1	200	168	126
MZFLY-18D120T151RH-440	150	440	620	2.1	200	168	126
MZFLY-18D120T201RH-440	200	440	620	2.1	200	168	126
MZFLY-18D120T251RH-440	250	440	620	2.1	200	168	126
MZFLY-18D120T401RH-440	400	440	620	2.1	200	168	126
MZFLY-18D120T501RH-440	500	440	620	2.1	200	168	126
MZFLY-18D120T801RH-440	800	440	620	2.1	200	168	126
MZFLY-18D120T102RH-440	1000	440	620	2.1	200	168	126
MZFLY-18D130T56RH-440	56	440	620	2.1	220	190	147
MZFLY-18D135T30RH-440	30	440	620	2.1	230	200	157
MZFLY-20D120T30RH-440	30	440	620	2.6	247	208	156
MZFLY-20D120T45RH-440	45	440	620	2.6	247	208	156
MZFLY-20D120T50RH-440	50	440	620	2.6	247	208	156
MZFLY-20D120T70RH-440	70	440	620	2.6	247	208	156
MZFLY-20D120T101RH-440	100	440	620	2.6	247	208	156
MZFLY-20D120T151RH-440	150	440	620	2.6	247	208	156
MZFLY-20D120T201RH-440	200	440	620	2.6	247	208	156
MZFLY-20D120T251RH-440	250	440	620	2.6	247	208	156
MZFLY-20D120T401RH-440	400	440	620	2.6	247	208	156
MZFLY-20D120T501RH-440	500	440	620	2.6	247	208	156
MZFLY-20D120T801RH-440	800	440	620	2.6	247	208	156
MZFLY-20D120T102RH-440	1000	440	620	2.6	247	208	156
MZFLY-20D130T56RH-440	56	440	620	2.6	273	234	182
MZFLY-20D135T30RH-440	30	440	620	2.6	286	247	195
MZFLY-22D120T30RH-440	30	440	620	3.5	322	280	210
MZFLY-22D120T45RH-440	45	440	620	3.5	322	280	210
MZFLY-22D120T50RH-440	50	440	620	3.5	322	280	210
MZFLY-22D120T70RH-440	70	440	620	3.5	322	280	210
MZFLY-22D120T101RH-440	100	440	620	3.5	322	280	210
MZFLY-22D120T151RH-440	150	440	620	3.5	322	280	210
MZFLY-22D120T201RH-440	200	440	620	3.5	322	280	210
MZFLY-22D120T251RH-440	250	440	620	3.5	322	280	210
MZFLY-22D120T401RH-440	400	440	620	3.5	322	280	210
MZFLY-22D120T501RH-440	500	440	620	3.5	322	280	210
MZFLY-22D120T801RH-440	800	440	620	3.5	322	280	210
MZFLY-22D120T102RH-440	1000	440	620	3.5	322	280	210
MZFLY-27D120T25RH-440	25	440	620	5.4	513	432	324
MZFLY-27D120T30RH-440	30	440	620	5.4	513	432	324
MZFLY-27D120T45RH-440	45	440	620	5.4	513	432	324
MZFLY-27D120T50RH-440	50	440	620	5.4	513	432	324
MZFLY-27D120T70RH-440	70	440	620	5.4	513	432	324
MZFLY-27D120T101RH-440	100	440	620	5.4	513	432	324
MZFLY-27D120T151RH-440	150	440	620	5.4	513	432	324
MZFLY-27D120T201RH-440	200	440	620	5.4	513	432	324
MZFLY-27D120T251RH-440	250	440	620	5.4	513	432	324
MZFLY-27D120T401RH-440	400	440	620	5.4	513	432	324
MZFLY-27D120T501RH-440	500	440	620	5.4	513	432	324
MZFLY-27D120T801RH-440	800	440	620	5.4	513	432	324
MZFLY-27D120T102RH-440	1000	440	620	5.4	513	432	324
Power frequency voltage 480Vac
MZFLY-18D130T121RH-480	120	480	680	2.1	220	189	147
Power frequency voltage 560Vac
MZFLY-14D110T501RH-560	500	560	800	1.4	120	98	70
MZFLY-18D130T101RH-560	100	560	800	2.3	241	207	161
Power frequency voltage 680Vac
MZFLY-14D120T50RH-680	50	680	1000	2.2	210	176	132
MZFLY-14D120T70RH-680	70	680	1000	2.2	210	176	132
MZFLY-14D120T101RH-680	100	680	1000	2.2	210	176	132
MZFLY-14D120T121RH-680	120	680	1000	2.2	210	176	132
MZFLY-14D120T151RH-680	150	680	1000	2.2	210	176	132
MZFLY-14D120T201RH-680	200	680	1000	2.2	210	176	132
MZFLY-14D120T251RH-680	250	680	1000	2.2	210	176	132
MZFLY-14D120T351RH-680	350	680	1000	2.2	210	176	132
MZFLY-14D120T501RH-680	500	680	1000	2.2	210	176	132
MZFLY-14D120T801RH-680	800	680	1000	2.2	210	176	132
MZFLY-14D120T102RH-680	1000	680	1000	2.2	210	176	132
MZFLY-18D120T50RH-680	50	680	1000	3.5	322	280	210
MZFLY-18D120T70RH-680	70	680	1000	3.5	322	280	210
MZFLY-18D120T101RH-680	100	680	1000	3.5	322	280	210
MZFLY-18D120T151RH-680	150	680	1000	3.5	322	280	210
MZFLY-18D120T201RH-680	200	680	1000	3.5	322	280	210
MZFLY-18D120T251RH-680	250	680	1000	3.5	322	280	210
MZFLY-18D120T401RH-680	400	680	1000	3.5	322	280	210
MZFLY-18D120T501RH-680	500	680	1000	3.5	322	280	210
MZFLY-18D120T801RH-680	800	680	1000	3.5	322	280	210
MZFLY-18D120T102RH-680	1000	680	1000	3.5	322	280	210
MZFLY-20D120T50RH-680	50	680	1000	4.5	428	360	270
MZFLY-20D120T70RH-680	70	680	1000	4.5	428	360	270
MZFLY-20D120T101RH-680	100	680	1000	4.5	428	360	270
MZFLY-20D120T151RH-680	150	680	1000	4.5	428	360	270
MZFLY-20D120T201RH-680	200	680	1000	4.5	428	360	270
MZFLY-20D120T251RH-680	250	680	1000	4.5	428	360	270
MZFLY-20D120T401RH-680	400	680	1000	4.5	428	360	270
MZFLY-20D120T501RH-680	500	680	1000	4.5	428	360	270
MZFLY-20D120T801RH-680	800	680	1000	4.5	428	360	270
MZFLY-20D120T102RH-680	1000	680	1000	4.5	428	360	270
MZFLY-22D120T50RH-680	50	680	1000	5.45	517	436	320
MZFLY-22D120T70RH-680	70	680	1000	5.45	517	436	320
MZFLY-22D120T101RH-680	100	680	1000	5.45	517	436	320
MZFLY-22D120T151RH-680	150	680	1000	5.45	517	436	320
MZFLY-22D120T201RH-680	200	680	1000	5.45	517	436	320
MZFLY-22D120T251RH-680	250	680	1000	5.45	517	436	320
MZFLY-22D120T401RH-680	400	680	1000	5.45	517	436	320
MZFLY-22D120T501RH-680	500	680	1000	5.45	517	436	320
MZFLY-22D120T801RH-680	800	680	1000	5.45	517	436	320
MZFLY-22D120T102RH-680	1000	680	1000	5.45	517	436	320
MZFLY-27D120T30RH-680	30	680	1000	8.50	810	680	510
MZFLY-27D120T45RH-680	45	680	1000	8.50	810	680	510
MZFLY-27D120T50RH-680	50	680	1000	8.50	810	680	510
MZFLY-27D120T70RH-680	70	680	1000	8.50	810	680	510
MZFLY-27D120T101RH-680	100	680	1000	8.50	810	680	510
MZFLY-27D120T151RH-680	150	680	1000	8.50	810	680	510
MZFLY-27D120T201RH-680	200	680	1000	8.50	810	680	510
MZFLY-27D120T251RH-680	250	680	1000	8.50	810	680	510
MZFLY-27D120T401RH-680	400	680	1000	8.50	810	680	510
MZFLY-27D120T501RH-680	500	680	1000	8.50	810	680	510
MZFLY-27D120T801RH-680	800	680	1000	8.50	810	680	510
MZFLY-27D120T102RH-680	1000	680	1000	8.50	810	680	510

 

l Typical application circuit:

　　

 

Ⅱ Selection

Select the charging capacitor according to the following formula

　　

 

C: filter capacitor. 0.7: safety factor

Tc: Curie temperature of PTC Ta: Ambient temperature

V: Capacitor charging voltage (V = 1.414xVs)

ENon60=0.7x(Tc-Ta)xCth ENon60=0.7xth

ENon60: maximum inaction energy @ 60 ℃(Ta = 60)