Understanding PWM (Pulse Width Modulation)

In this article:

Overview

Pulse Width Modulation (PWM) is a widely used technique in electronics and digital systems to control the power supplied to electrical devices such as motors, LEDs, heaters, and more.

It operates by varying the width of pulses in a digital signal to adjust the average power delivered to the load.

Within zappi 1% increment of PWM, the EVSE (Zappi) is telling the EV that it can charge by an increment of 0.6 Amps per phase.

Where to find PWM

Access the Menu: Press the Menu button on the zappi (3-line button).

Navigate to Readings: Once in the menu, use the arrow buttons or touch screen to navigate to the "Readings" menu.

Readings - Page 1: Towards the bottom of the screen you will see Pilot (PWM).

PWM Range

zappi will operate a PWM range of 10%-53% (6A to 32 Amps per phase).

PWM To kW / AMP Chart

PWM %	Current/A	Power/W @230V	PWM %	Current/A	Power/W @230V
10	6	1380	32	19.2	4416
11	6.6	1518	33	19.8	1554
12	7.2	1656	34	20.4	1692
13	7.8	1794	35	21	4830
14	8.4	1932	36	21.6	4968
15	9	2070	37	22.2	5106
16	9.6	2208	38	22.8	5244
17	10.2	2346	39	23.4	5382
18	10.8	2484	40	24	5520
19	11.4	2622	41	24.6	5658
20	12	2760	42	25.2	5796
21	12.6	2898	43	25.8	5934
22	13.2	3036	44	26.4	6072
23	13.8	3174	45	27	6210
24	14.4	3312	46	27.6	6348
25	15	3450	47	28.2	6486
26	15.6	3588	48	28.8	6624
27	16.2	3726	49	29.4	6762
28	16.8	3864	50	30	6900
29	17.4	4002	51	30.6	7038
30	18	4140	52	31.2	7176
31	18.6	4278

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